Process for transmitting information bits with error correction coding and decoder for the implementation of this process
First Claim
1. Process for transmitting information bits, wherein a transmitter executes the following steps:
- forming a first binary matrix from the information bits to be transmitted;
converting the first binary matrix into a second binary matrix by applying a systematic block code corresponding to a product of elementary systematic block codes; and
transmitting bits extracted from the second binary matrix towards a channel, and a receiver executes the following steps;
forming an input matrix from a signal received according to said channel, the input matrix having the same size as the second binary matrix, and being comprised of digital samples having signs which represent respective initial estimations of the bits in the second binary matrix and absolute values which respectively measure confidences associated with said initial estimations; and
iteratively decoding the input matrix, wherein the iterative decoding of the input matrix includes a number m of decoding cycles, each decoding cycle successively comprising code word search steps for each elementary block code used in the product code, wherein, at each code word search step, a data matrix and a decision matrix having binary components are received which, before the first search step of the iterative decoding are respectively constituted by the input matrix and by a matrix having binary components which respectively correspond to the signs of the input matrix samples, and a new decision matrix and a new data matrix are produced for the following search step, whereby the new decision matrix has binary components which represent new respective estimations of the bits of the second binary matrix and the new data matrix has samples having absolute values which respectively measure confidences associated with said new estimations, wherein decoded information bits are extracted from the decision matrix produced during the last code word search step, wherein each code word search step includes a division of the data matrix received into data vectors each corresponding to a code word of the elementary code and a corresponding division of the decision matrix received into decision vectors and soft decision elementary decodings to respectively process at least certain data vector/decision vector pairs, wherein the first binary matrix comprises, in addition to the information bits, a set of bits having values a priori known to the receiver, the bits of said set being distributed in a substantially uniform manner according to each dimension of the first binary matrix, whereby, after systematic coding, the bits of said set are located in determined positions of said second binary matrix, wherein the bits of said set are not transmitted towards the channel, and wherein the receiver places in the input matrix, in positions corresponding to said determined positions of the second binary matrix, samples having signs which correspond respectively to the a priori known values of the bits of said set and absolute values which are representative of a maximum confidence.
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Abstract
The bits transmitted are coded according to the product of at least two systematic block codes. Iterative decoding is applied in order to determine, at each code word search step, a data matrix ({R}) and a decision matrix ({D}) used for the following step. The new decision matrix is determined at each step by decoding the lines or columns of the input matrix, and the new data matrix is determined taking into account the correction terms which increase the reliability of the decoding on each iteration. The coding and decoding circuits (17) are rendered programmable by a shortening technique allowing selection of the number k-X of non-redundant information bits per block to be coded. Known values are assigned to the other bits, the positions of which are uniformly distributed according to each dimension of the matrices.
188 Citations
7 Claims
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1. Process for transmitting information bits, wherein a transmitter executes the following steps:
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forming a first binary matrix from the information bits to be transmitted; converting the first binary matrix into a second binary matrix by applying a systematic block code corresponding to a product of elementary systematic block codes; and transmitting bits extracted from the second binary matrix towards a channel, and a receiver executes the following steps; forming an input matrix from a signal received according to said channel, the input matrix having the same size as the second binary matrix, and being comprised of digital samples having signs which represent respective initial estimations of the bits in the second binary matrix and absolute values which respectively measure confidences associated with said initial estimations; and iteratively decoding the input matrix, wherein the iterative decoding of the input matrix includes a number m of decoding cycles, each decoding cycle successively comprising code word search steps for each elementary block code used in the product code, wherein, at each code word search step, a data matrix and a decision matrix having binary components are received which, before the first search step of the iterative decoding are respectively constituted by the input matrix and by a matrix having binary components which respectively correspond to the signs of the input matrix samples, and a new decision matrix and a new data matrix are produced for the following search step, whereby the new decision matrix has binary components which represent new respective estimations of the bits of the second binary matrix and the new data matrix has samples having absolute values which respectively measure confidences associated with said new estimations, wherein decoded information bits are extracted from the decision matrix produced during the last code word search step, wherein each code word search step includes a division of the data matrix received into data vectors each corresponding to a code word of the elementary code and a corresponding division of the decision matrix received into decision vectors and soft decision elementary decodings to respectively process at least certain data vector/decision vector pairs, wherein the first binary matrix comprises, in addition to the information bits, a set of bits having values a priori known to the receiver, the bits of said set being distributed in a substantially uniform manner according to each dimension of the first binary matrix, whereby, after systematic coding, the bits of said set are located in determined positions of said second binary matrix, wherein the bits of said set are not transmitted towards the channel, and wherein the receiver places in the input matrix, in positions corresponding to said determined positions of the second binary matrix, samples having signs which correspond respectively to the a priori known values of the bits of said set and absolute values which are representative of a maximum confidence. - View Dependent Claims (2, 3, 4, 5)
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6. Redundancy coder, comprising:
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means to form a first binary matrix from information bits to be transmitted; elementary coding means controlled to convert the first binary matrix into a second binary matrix by application of a systematic block code corresponding to a product of elementary systematic block codes; means to transmit bits extracted from the second binary matrix towards a channel; and programming means to determine, from a number X supplied to program the number of information bits to be included in each first matrix, X positions uniformly distributed according to each dimension of the first matrix, wherein the means of forming the first matrix are designed to place bits of known values in said X positions, whereby said bits of known values are located after systematic coding in determined positions of the second binary matrix, and wherein said means to transmit do not include said bits of known values located at determined positions after systematic coding in the bits transmitted towards the channel.
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7. Error correction decoder, comprising:
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means for forming an input matrix from a signal received according to a transmission channel, the input matrix being composed of digital samples the signs of which represent respective initial estimations of bits of a binary matrix formed by a redundancy coder applying a systematic block code corresponding to a product of elementary systematic block codes and the absolute values of which respectively measure confidences associated with said initial estimations; and iterative decoding means controlled to decode the input matrix according to successive decoding cycles, each decoding cycle successively comprising steps for searching code words o each elementary block code used in the product code, wherein, at each code word search step, the decoding means receive a data matrix and a decision matrix having binary components which, before the first search step of the iterative decoding, are respectively constituted by the input matrix and a matrix having binary components which correspond to the signs of samples of the input matrix, and produce a new decision matrix and a new data matrix for the following search step, whereby the new decision matrix has binary components which represent new respective estimations of the bits of the second binary matrix and the new data matrix has samples having absolute values which respectively measure confidences associated with said new estimations, wherein decoded information bits are extracted from the decision matrix produced during the last step of the code word search, and wherein each code word search step includes a division of the data matrix received into data vectors each corresponding to a code word of the elementary code and a corresponding division of the decision matrix received into decision vectors and elementary soft decision decodings respectively process at least certain data vector/decision vector pairs, the error correction decoder further comprising programming means to determine, from a number X supplied to program the number of decoded information bits to be extracted from the decision matrix, X positions uniformly distributed according to each dimension of a non-redundant sub-matrix of said binary matrix, and wherein the means for forming the input matrix are designed to place, in positions corresponding to said X positions, digital samples of determined signs having absolute values representative of a maximum confidence.
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Specification