Method and apparatus for channel encoding and decoding in a communication system using a low-density parity check code
A method is provided for channel encoding in a communication system using a Low-Density Parity Check (LDPC) code. The method includes grouping information bits into a plurality of groups; determining an order of the plurality of groups to be shortened, based on a ratio of a number of bits to be shortened to a number of bits to be punctured; determining a length of an information word to be obtained by shortening the plurality of groups; shortening the plurality of groups on a group basis in the determined order based on the determined length of the information word; and LDPC-encoding a shortened information word.
1. A method for channel encoding in a communication system using a Low-Density Parity Check (LDPC) code, comprising:
grouping information bits into a plurality of groups;
determining an order of the plurality of groups to be shortened, based on a ratio of a number of bits to be shortened to a number of bits to be punctured;
determining a length of information bits to be obtained by shortening the plurality of groups;
shortening the plurality of groups on a group basis in the determined order, based on the determined length of the information bits; and
LDPC-encoding the shortened information bits.
2. The method of claim 1 , wherein each of the plurality of groups includes at least one of a bit group and a column group.
3. The method of claim 1 , wherein if a length of the LDPC codeword is 16200, a length of the information bits is 3240, and the ratio of the number of bits to be shortened to the number of bits to be punctured is 4/15 or 3/11, shortening is performed on 7 th , 6 th , 3 rd , 5 th , 2 nd , 4 th , 1 st , 8 th , and 0 th groups among the plurality of groups, in order, as defined in,
Number of information bits to be shortened/number of bits to be
punctured = 4/15, 3/11
π(0)
π(1)
π(2)
π(3)
π(4)
π(5)
π(6)
π(7)
π(8)
7
6
3
5
2
4
1
8
0
and
wherein if the length of the LDPC codeword is 16200, the length of the information bits is 3240, and the ratio of the number of bits to be shortened to the number of bits to be punctured is 2/7, shortening is performed on the 7 th , 3 rd , 6 th , 5 th , 2 nd , 4 th , 1 st , 8 th , and 0 th groups among the plurality of groups, in order, as defined in,
Number of information bits to be shortened/number of bits to be
punctured = 2/7
π(0)
π(1)
π(2)
π(3)
π(4)
π(5)
π(6)
π(7)
π(8)
7
3
6
5
2
4
1
8
0.
4. An apparatus for channel encoding in a communication system using a Low-Density Parity Check (LDPC) code, comprising:
a parity check matrix extractor for grouping information bits into a plurality of groups, and determining an order of the plurality of groups to be shortened, based on a ratio of a number of bits to be shortened to a number of bits to be punctured;
a shortening pattern applying unit for determining a length of information bits to be obtained by shortening, and shortening the plurality of groups on a group basis in the determined shortening order, based on the determined length of the information bits; and
an encoder for LDPC-encoding a shortened information bits.
5. The apparatus of claim 4 , wherein if a length of the LDPC codeword is 16200, a length of the information bits is 3240, and the ratio of the number of bits to be shortened to the number of bits to be punctured is 4/15 or 3/11, the shortening pattern applying unit performs shortening on 7 th , 6 th , 3 rd , 5 th , 2 nd , 4 th , 1 st , 8 th , and 0 th groups among the plurality of groups, in order, as defined in,
Number of information bits to be shortened/number of bits to be
punctured = 4/15, 3/11
π(0)
π(1)
π(2)
π(3)
π(4)
π(5)
π(6)
π(7)
π(8)
7
6
3
5
2
4
1
8
0
and
wherein if the length of the LDPC codeword is 16200, the length of the information bits is 3240, and the ratio of the number of bits to be shortened to the number of bits to be punctured is 2/7, the shortening pattern applying unit performs shortening on the 7 th , 3 rd , 6 th , 5 th , 2 nd , 4 th , 1 st , 8 th , and 0 th groups among the plurality of groups, in order, as defined in,
Number of information bits to be shortened/number of bits to be
punctured = 2/7
π(0)
π(1)
π(2)
π(3)
π(4)
π(5)
π(6)
π(7)
π(8)
7
3
6
5
2
4
1
8
0.
6. The apparatus of claim 4 , wherein each of the plurality of groups includes at least one of a bit group and a column group.
7. A method for channel decoding in a communication system using a Low-Density Parity Check (LDPC) code, comprising:
demodulating a signal transmitted from a transmitter;
determining from the demodulated signal whether a shortened bit exists;
if the shortened bit exists, determining a group of the shortened bit using a shortening pattern determined based on a ratio of a number of bits to be shortened to a number of bits to be punctured by the transmitter; and
decoding data using the determined group of the shortened bit,
wherein the shortening pattern is determined on a group basis.
8. The method of claim 7 , wherein if a length of the LDPC codeword is 16200, a length of information bits is 3240, and the ratio of the number of bits to be shortened to the number of bits to be punctured is 4/15 or 3/11, then 7 th , 6 th , 3 rd , 5 th , 2 nd , 4 th , 1 st , 8 th , and 0 th groups are determined, in order, as shortened groups, as defined in,
Number of information bits to be shortened/number of bits to be
punctured = 4/15, 3/11
π(0)
π(1)
π(2)
π(3)
π(4)
π(5)
π(6)
π(7)
π(8)
7
6
3
5
2
4
1
8
0
and
wherein if the length of the LDPC codeword is 16200, the length of the information bits is 3240, and the ratio of the number of bits to be shortened to the number of bits to be punctured is 2/7, then the 7 th , 3 rd , 6 th , 5 th , 2 nd , 4 th , 1 st , 8 th , and 0 th groups are determined, in order, as the shortened groups, as defined in,
Number of information bits to be shortened/number of bits to be
punctured = 2/7
π(0)
π(1)
π(2)
π(3)
π(4)
π(5)
π(6)
π(7)
π(8)
7
3
6
5
2
4
1
8
0.
9. The method of claim 7 , wherein the group includes at least one of a bit group and a column group.
10. An apparatus for channel decoding in a communication system using a Low-Density Parity Check (LDPC) code, comprising:
a demodulator for demodulating a signal transmitted from a transmitter;
a shortening pattern determiner for determining from the demodulated signal whether a shortened bit exists, and if the shortened bit exists, determining a group of the shortened bit using a shortening pattern determined based on a ratio of a number of bits to be shortened to a number of bits to be punctured; and
a decoder for decoding data using the determined group of the shortened bit,
wherein the shortening pattern is determined on a group basis.
11. The apparatus of claim 10 , wherein if a length of the LDPC codeword is 16200, a length of information bits is 3240, and the ratio of the number of bits to be shortened to the number of bits to be punctured is 4/15 or 3/11, then 7 th , 6 th , 3 rd , 5 th , 2 nd , 4 th , 1 st , 8 th , and 0 th groups are determined, in order, as shortened groups, as defined in,
Number of information bits to be shortened/number of bits to be
punctured = 4/15, 3/11
π(0)
π(1)
π(2)
π(3)
π(4)
π(5)
π(6)
π(7)
π(8)
7
6
3
5
2
4
1
8
0
and
wherein if the length of the LDPC codeword is 16200, the length of the information bits is 3240, and the ratio of the number of bits to be shortened to the number of bits to be punctured is 2/7, then the 7 th , 3 rd , 6 th , 5 th , 2 nd , 4 th , 1 st , 8 th , and 0 th groups are determined, in order, as the shortened groups, as defined in,
Number of information bits to be shortened/number of bits to be
punctured = 2/7
π(0)
π(1)
π(2)
π(3)
π(4)
π(5)
π(6)
π(7)
π(8)
7
3
6
5
2
4
1
8
0.
12. The apparatus of claim 10 , wherein the group includes at least one of a bit group and a column group.