Method and apparatus of encoding and decoding data using low density parity check code in a wireless communication system
A method of encoding data using low density parity check (LDPC) code defined by a m×n parity check matrix is disclosed. More specifically, the method includes encoding input source data using the parity check matrix, wherein the parity check matrix comprises a plurality of z×z sub-matrices of which row weights and column weights are ‘0’ or ‘1’.
1. A method of decoding encoded data using low density parity check (LDPC) code, the method comprising:
providing a first base matrix including a first value as each element of the first base matrix, the first value an integer which indicates either a zero matrix or a first permutation matrix having a z max ×z max size;
generating a second base matrix by replacing each first value corresponding to each element of the first base matrix with a second value corresponding to each element of the second base matrix, the second value an integer which indicates either a zero matrix or a second permutation matrix having a z×z size;
generating a parity check matrix by replacing each second value of the second base matrix with a corresponding second permutation matrix or the zero matrix having the z×z size; and
using the parity check matrix to decode the encoded data,
wherein z max is greater than z, and wherein each second value is determined based on z, z max , and each corresponding first value.
2. The method of claim 1 , wherein the second value corresponding to each element of the second base matrix is either a non-negative integer or “−1” and generating the parity check matrix further comprises:
replacing the second value of “−1” with the zero matrix having the z×z size;
replacing the second value of the positive integer with a second permutation matrix having the z×z size, the second permutation matrix altered from an identity matrix having the z×z size according to the positive integer; and
replacing the second value of a zero with a second permutation matrix that is the identity matrix having the z×z size.
3. The method of claim 2 , wherein altering the second permutation matrix comprises circular shifting either each entire row or each entire column of the identity matrix a number of intervals equal to the positive integer.
4. The method of claim 1 , wherein each of the first permutation matrix and second permutation matrix is defined as having a row weight and column weight of “1”.
5. The method of claim 1 , wherein the number of rows of the second base matrix is equal to the number of columns in the parity check matrix divided by z and multiplied by (1—(a coding rate)).
6. The method of claim 1 , wherein each second value is determined based on the following equation:
shift(z)=floor (shift (z max ) z/z max ), where “shift (z max )” is the first value, “shift(z)” is the second value, and “floor (x)” denotes a nearest integer from x toward negative infinity.
7. The method of claim 1 , wherein at least two continuous integers corresponding to the first value are grouped and mapped to one second value when determining each second value.
8. The method of claim 1 , wherein generating the second matrix further comprises replacing a first value that indicates the zero matrix having the z max ×z max size with a second value that indicates the zero matrix having the z×z size.
9. An apparatus for decoding encoded data using low density parity check (LDPC) code, the apparatus comprising:
a base matrix generation module to generate a second base matrix by replacing each first value corresponding to each element of a first base matrix with a second value corresponding to each element of the second base matrix, wherein each first value of the first base matrix is an integer that indicates either a zero matrix or a first permutation matrix having a z max ×z max size and each second value of the second base matrix is an integer that indicates either a zero matrix or a second permutation matrix having a z×z size;
a parity check matrix generation module to generate a parity check matrix by replacing each second value of the second base matrix with a corresponding second permutation matrix or the zero matrix having the z×z size; and
a decoding module to decode the encoded data using the parity check matrix,
wherein z max is greater than z and each second value is determined based on z, z max , and each corresponding first value.
10. The apparatus of claim 9 , wherein the second value corresponding to each element of the second base matrix is either a non-negative integer or “−1” and the parity check matrix generation module comprises:
means for replacing the second value of “−1” with the zero matrix having the z×z size;
means for replacing the second value of the positive integer with a second permutation matrix having the z×z size, the second permutation matrix altered from an identity matrix having the z×z size according to the positive integer; and
means for replacing the second value of a zero with a second permutation matrix that is the identity matrix having the z×z size.
11. The apparatus of claim 10 , wherein the second permutation matrix indicated by the positive integer is altered by circular shifting either each entire row or each entire column of the identity matrix a number of intervals equal to the positive integer.
12. The apparatus of claim 9 , wherein each of the first permutation matrix and second permutation matrix is defined as having a row weight and column weight of “1”.
13. The apparatus of claim 9 , wherein the number of rows of the second base matrix is equal to the number of columns in the parity check matrix divided by z and multiplied by (1—(a coding rate)).
14. The apparatus of claim 9 , wherein the base matrix generation module determines each second value based on the following equation:
shift(z)=floor (shift (z max ) z/z max ), where “shift (z max )” is the first value, “shift(z)” is the second value, and “floor (x)” denotes a nearest integer from x toward negative infinity.
15. The apparatus of claim 9 , wherein at least two continuous integers corresponding to the first value are grouped and mapped to one second value when determining each second value.
16. The apparatus of claim 9 , wherein the base matrix generation module replaces a first value that indicates the zero matrix having the z max ×z max size with a second value that indicates the zero matrix having the z×z size.