Excavating
Patent
1985-08-19
1988-01-12
Smith, Jerry
Excavating
371 37, G06F 1110
Patent
active
047196289
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a method and an apparatus for decoding error correction code.
BACKGROUND ART
Product codes are well known such that information symbols are arranged in two-dimensional form; error correction codes are encoded for each row and column on the two-dimensional arrangement so that each information symbol is included in two error correction code series. In decoding the product code, an error correction code is decoded for each column, and an error correction code can be decoded for each row by employing the decoded information. The decoded information is called a pointer.
In the conventional method, since each information symbol is associated with a pointer, it is required that the total number of pointers is at least equal to the number of the information symbols.
Further, in the case where erasure correction is made by employing the pointers, since the pointers are read out from a pointer memory and the error values are calculated for every row, there exists a problem in that the number of processing steps such as memory accesses, calculations and so on inevitably increases.
On the other hand, in the case where complicated codes such as BCH codes are employed as error correction codes, since the operations for obtaining error values become inevitably complicated, there exists a problem in that a great number of program steps are required in the case where the calculations are implemented by hardware.
DISCLOSURE OF THE INVENTION
An object of this invention is to provide a method and an apparatus for decoding error correction codes which enable one to reduce the number of pointers required in decoding as well as the memory space required for pointers and to reduce the number needed for times of reading and writing the pointers.
Another object of this invention is to provide a method and an apparatus for decoding error correction codes which enable one to markedly reduce the number of processing steps in dependence upon the fact that the pointers with respect to each row are the same.
Still another object of this invention is to provide an apparatus for decoding error correction codes which enables one to reduce the number of calculating steps in an erasure correction.
A still further object of this invention is to provide a method for decoding error correction codes which can obtain error values in decoding in dependence upon a simple construction and using a small number of processing steps.
To achieve the above mentioned technical task, the present invention provides a method of decoding error correction code in which first error correction code of (n.sub.1, k.sub.1) (where n.sub.1 denotes the code length) are encoded for every k.sub.1 information symbols in each column of two-dimensional arrangement (k.sub.1 .times.k.sub.2) and second error correction code of (n.sub.2, k.sub.2) (where n.sub.2 denotes the code length) are encoded for every k.sub.2 information symbols in each row, the method for decoding error correction code comprises the steps of storing first pointers formed by decoding the first error correction code in a memory having n.sub.2 bits, storing second pointers formed by decoding the second error correction code in at least a memory having k.sub.1 bits, and evaluating the reliability on the basis of the status of the first and second pointers in outputting the information symbols.
Further, in the present invention, a method of decoding error correction codes comprises the steps of storing first pointers formed by decoding the first error correction code in a memory having n.sub.2 bits, implementing erasure correction with respect to each code series of the second error correction code by employing the first pointer and implementing a part of calculations for obtaining error values in the erasure correction only once with respect to each code series of the second error correction code in decoding the second error correction code.
Further, in the present invention, paying attention to the fact that in linear non-dualistic code having a root of 1, one
REFERENCES:
patent: 3714629 (1973-01-01), Hong
patent: 4030067 (1977-06-01), Howell
patent: 4142174 (1979-02-01), Chen
patent: 4236247 (1980-11-01), Sundberg
patent: 4546474 (1985-10-01), Sako
patent: 4646301 (1987-02-01), Okamoto
U. Olderdissen, "Fast Double Error Correction", IBM TDM, vol. 25, No. 5, 10/1982, pp. 2343-2346.
Fukumi Tadashi
Odaka Kentaro
Ozaki Shinya
Beausoliel, Jr. Robert W.
Smith Jerry
Sony Corporation
LandOfFree
Method and apparatus for decoding error correction code does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for decoding error correction code, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for decoding error correction code will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-924443