GB2013002A - Improvements in error correction devices - Google Patents

Improvements in error correction devices

Info

Publication number
GB2013002A
GB2013002A GB7901459A GB7901459A GB2013002A GB 2013002 A GB2013002 A GB 2013002A GB 7901459 A GB7901459 A GB 7901459A GB 7901459 A GB7901459 A GB 7901459A GB 2013002 A GB2013002 A GB 2013002A
Authority
GB
United Kingdom
Prior art keywords
shift register
values
bit
likelihood
repeated
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB7901459A
Other versions
GB2013002B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Plessey Co Ltd
Original Assignee
Plessey Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Plessey Co Ltd filed Critical Plessey Co Ltd
Priority to GB7901459A priority Critical patent/GB2013002B/en
Publication of GB2013002A publication Critical patent/GB2013002A/en
Application granted granted Critical
Publication of GB2013002B publication Critical patent/GB2013002B/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
    • H04L1/0056—Systems characterized by the type of code used
    • H04L1/0057—Block codes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/03—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words
    • H03M13/05—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits
    • H03M13/11—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits using multiple parity bits
    • H03M13/1102—Codes on graphs and decoding on graphs, e.g. low-density parity check [LDPC] codes
    • H03M13/1105—Decoding
    • H03M13/1111—Soft-decision decoding, e.g. by means of message passing or belief propagation algorithms
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/03—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words
    • H03M13/05—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits
    • H03M13/11—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits using multiple parity bits
    • H03M13/1102—Codes on graphs and decoding on graphs, e.g. low-density parity check [LDPC] codes
    • H03M13/1105—Decoding
    • H03M13/1111—Soft-decision decoding, e.g. by means of message passing or belief propagation algorithms
    • H03M13/1114—Merged schedule message passing algorithm with storage of sums of check-to-bit node messages or sums of bit-to-check node messages, e.g. in order to increase the memory efficiency
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/03—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words
    • H03M13/05—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits
    • H03M13/11—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits using multiple parity bits
    • H03M13/1102—Codes on graphs and decoding on graphs, e.g. low-density parity check [LDPC] codes
    • H03M13/1191—Codes on graphs other than LDPC codes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/37—Decoding methods or techniques, not specific to the particular type of coding provided for in groups H03M13/03 - H03M13/35
    • H03M13/3746—Decoding methods or techniques, not specific to the particular type of coding provided for in groups H03M13/03 - H03M13/35 with iterative decoding
    • H03M13/3753—Decoding methods or techniques, not specific to the particular type of coding provided for in groups H03M13/03 - H03M13/35 with iterative decoding using iteration stopping criteria
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/37—Decoding methods or techniques, not specific to the particular type of coding provided for in groups H03M13/03 - H03M13/35
    • H03M13/45—Soft decoding, i.e. using symbol reliability information
    • H03M13/458—Soft decoding, i.e. using symbol reliability information by updating bit probabilities or hard decisions in an iterative fashion for convergence to a final decoding result
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/65—Purpose and implementation aspects
    • H03M13/6597—Implementations using analogue techniques for coding or decoding, e.g. analogue Viterbi decoder
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/03—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words
    • H03M13/05—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits
    • H03M13/13—Linear codes
    • H03M13/15—Cyclic codes, i.e. cyclic shifts of codewords produce other codewords, e.g. codes defined by a generator polynomial, Bose-Chaudhuri-Hocquenghem [BCH] codes

Abstract

A codeword generated by a feedback shift register and received after transmission over a noisy channel is stored in a shift register 5 as a set of analogue voltages (or digitised versions thereof). With binary values initially represented as equal voltages of opposite polarity, the value Ii in each shift register stage represents, according to its sign, the likelihood of the corresponding codeword bit being 0 or 1 &cirf& The likelihood values for a given bit bi and two further bits bi+s, bi+t, with which the bit bi has a known parity relationship, are used to compute (6) an enhanced likelihood value Ii' for re-insertion into the shift register 5 or insertion into another shift register for subsequent processing. All values Ii are thus treated in turn for N</=i</=o and the process repeated for a different pair of s and t, (though all pairs s,t could be run through for bi before passing on to the next bit). The entire process is repeated for as many times as is necessary for the values Ii' of at least the data bits to exceed a pre- set threshold. <IMAGE>
GB7901459A 1978-01-05 1979-01-15 Error correction devices Expired GB2013002B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB7901459A GB2013002B (en) 1978-01-05 1979-01-15 Error correction devices

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB27678 1978-01-05
GB7901459A GB2013002B (en) 1978-01-05 1979-01-15 Error correction devices

Publications (2)

Publication Number Publication Date
GB2013002A true GB2013002A (en) 1979-08-01
GB2013002B GB2013002B (en) 1982-03-17

Family

ID=26235812

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7901459A Expired GB2013002B (en) 1978-01-05 1979-01-15 Error correction devices

Country Status (1)

Country Link
GB (1) GB2013002B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0963049A2 (en) * 1998-06-01 1999-12-08 Her Majesty The Queen In Right Of Canada as represented by the Minister of Industry Interleaving with golden section increments
US6339834B1 (en) 1998-05-28 2002-01-15 Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of Industry Through The Communication Research Centre Interleaving with golden section increments

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6339834B1 (en) 1998-05-28 2002-01-15 Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of Industry Through The Communication Research Centre Interleaving with golden section increments
EP0963049A2 (en) * 1998-06-01 1999-12-08 Her Majesty The Queen In Right Of Canada as represented by the Minister of Industry Interleaving with golden section increments
EP0963049A3 (en) * 1998-06-01 2001-03-28 Her Majesty The Queen In Right Of Canada as represented by the Minister of Industry Interleaving with golden section increments

Also Published As

Publication number Publication date
GB2013002B (en) 1982-03-17

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee