Method and device for delivering punctured code words encoded with a LDPC code

1. A method for delivering to a device punctured code words encoded with a Low-Density Parity-Check (LDPC) code defined by an original generator matrix having N rows and N−M columns, the method comprising:

determining at least one generator sub-matrix having N−M columns and N 1 rows by removing N−N 1 rows from the original generator matrix; and

delivering to the device the punctured encoded code word by receiving an input data vector of size N−M and multiplying the input data vector with the at least one generator sub-matrix.

2. The method according to claim 1 , wherein determining further comprises determining a set of generator sub-matrices having respectively N−M columns and N i rows, i being a positive integer greater than or equal to 2, and including removing N i −N i+l rows from the generator sub-matrix of rank i to obtain a generator sub-matrix of rank i+l having N i+1 rows; and wherein delivering comprises selecting one of the generator sub-matrices and multiplying the input vector by the selected generator sub-matrix for delivering the punctured encoded code word.

3. The method according to claim 1 , wherein the punctured code words encoded with an LDPC code are for a hybrid ARQ scheme with incremental redundancy including successive transmissions of successive punctured code words; wherein determining further comprises determining a set of i generator sub-matrixes having respectively N−M columns and N i rows, i being a positive integer greater than or equal to 2, and N i+l rows of the generator sub-matrix of rank i+1 being different from the rows of any generator sub-matrix having a rank less than i+1; and wherein the delivering comprises successive transmissions each including respectively selecting different generator sub-matrices and respectively multiplying successive input vectors by the successively selected generator sub-matrices for delivering successive punctured encoded code words.

4. The method according to claim 1 , wherein determining further comprises determining indexes of first and last rows of the at least one generator sub-matrix, and addressing the at least one generator sub-matrix based upon the original generator matrix and the indexes.

5. A method for generating for a device a code word encoded with a block code defined by a generator matrix having N rows and N−M columns, the method comprising:

determining at least one generator sub-matrix having N−M columns and N 1 rows by removing N−N l rows from the generator matrix; and

generating for the device the encoded code word based upon an input data vector of size N−M and the at least one generator sub-matrix.

6. The method according to claim 5 , wherein determining further comprises determining a set of generator sub-matrices having respectively N−M columns and N i rows, i being a positive integer greater than or equal to 2, and including removing N i −N i+1 rows from the generator sub-matrix of rank i to obtain a generator sub-matrix of rank i+l having N i+1 rows; and wherein generating the encoded code word comprises selecting one of the generator sub-matrices and multiplying the input vector by the selected generator sub-matrix.

7. The method according to claim 5 , wherein the code words are for a hybrid ARQ scheme with incremental redundancy including successive transmissions of successive code words; wherein determining further comprises determining a set of i generator sub-matrixes having respectively N−M columns and N i rows, i being a positive integer greater than or equal to 2, and N i+1 rows of the generator sub-matrix of rank i+1 being different from the rows of any generator sub-matrix having a rank less than i+1; and

wherein generating the encoded code word comprises successive transmissions each including respectively selecting different generator sub-matrices and respectively multiplying successive input vectors by the successively selected generator sub-matrices.

8. The method according to claim 5 , wherein determining further comprises determining indexes of first and last rows of the at least one generator sub-matrix, and addressing the at least one generator sub-matrix based upon the original generator matrix and the indexes.

9. A device for delivering punctured code words encoded with an LDPC code defined by an original generator matrix having N rows and N−M columns, the device comprising:

a generator to remove N−N 1 rows from the original generator matrix to obtaining at least one generator sub-matrix having N−M columns and N 1 rows;

an input to receive an input data vector of size N−M; and

a multiplier to multiply the input data vector with the generator sub-matrix to obtain the punctured encoded code word.

10. The device according to claim 9 , wherein the generator generates a set of generator sub-matrixes having respectively N−M columns and N i rows, i being a positive integer greater than or equal to 2, the generator removing N i −N i+1 rows from the generator sub-matrix of rank i to obtain generator sub-matrix of rank i+l having N i+1 rows; and further comprising a selector to select one of the generator sub-matrixes; wherein the multiplier multiplies the input vector by the selected generator sub-matrix to obtain the punctured encoded code word.

11. The device according to claim 9 , wherein the code words encoded with a LDPC code are for a hybrid ARQ scheme with incremental redundancy comprising successive transmissions of successive punctured code words; wherein the generator generates a set of generator sub-matrixes having respectively N−M columns and N i rows, i being a positive integer greater than or equal to 2, and N i+1 rows of the generator sub-matrix of rank i+l being different from the rows of any generator sub-matrix having a rank less than i+1; and further comprising a selector, for successive transmissions, to respectively select different generator sub-matrices; and the multiplier respectively multiplies successive input vectors by the successively selected generator sub-matrices to obtain successive punctured encoded code words.

12. The device according to claim 9 , further comprising a memory to store the original generator matrix and indexes of first and last rows of each generator sub-matrix; wherein the generator addresses a generator sub-matrix based upon the indexes and the original generator matrix.

13. A device for generating a code word encoded with a block code defined by a generator matrix having N rows and N−M columns, the device comprising:

a generator to remove N−N 1 rows from the generator matrix to obtaining at least one generator sub-matrix having N−M columns and N 1 rows; and

a block to obtain the encoded code word based upon an input data vector of size N−M and the at least one generator sub-matrix.

14. The device according to claim 13 , wherein the generator generates a set of generator sub-matrixes having respectively N−M columns and N i rows, i being a positive integer greater than or equal to 2, the generator removing N i −N i+1 rows from the generator sub-matrix of rank i to obtain generator sub-matrix of rank i+l having N i+1 rows; and further comprising a selector to select one of the generator sub-matrixes; wherein the block comprises a multiplier that multiplies the input vector by the selected generator sub-matrix to obtain the encoded code word.

15. The device according to claim 13 , wherein the code words are encoded with an LDPC code for a hybrid ARQ scheme with incremental redundancy comprising successive transmissions of successive punctured code words; wherein the generator generates a set of generator sub-matrixes having respectively N−M columns and N i rows, i being a positive integer greater than or equal to 2, and N i+1 rows of the generator sub-matrix of rank i+l being different from the rows of any generator sub-matrix having a rank less than i+1; and further comprising a selector, for successive transmissions, to respectively select different generator sub-matrices; and wherein the block comprises a multiplier respectively multiplying successive input vectors by the successively selected generator sub-matrices to obtain successive punctured encoded code words.

16. The device according to claim 13 , further comprising a memory to store the generator matrix and indexes of first and last rows of the at least one generator sub-matrix; wherein the generator addresses the at least one generator sub-matrix based upon the indexes and the original generator matrix.