Transmitter and repetition method thereof

1. A transmitter comprising:

a Low Density Parity Check (LDPC) encoder configured to encode input bits comprising zero bits to generate parity bits;

a repeater configured to append one or more bits of an LDPC codeword comprising the input bits and the parity bits to the input bits, the one or more bits of the LDPC codeword being repeated; and

a puncturer configured to puncture one or more bits of the parity bits,

wherein a number of bits to be repeated is determined based on a number of bits other than the zero bits in the input bits.

2. The transmitter of claim 1 , wherein the input bits comprise outer encoded bits, and the repeater is configured to calculate the number of bits to be repeated based on a number of the outer encoded bits.

3. The transmitter of claim 2 , wherein the repeater is configured to calculate the number of the bits to be repeated based on a following equation:

N repeat =2×└ C×N outer ┘+D,

where N repeat represents the number of the bits to be repeated, N outer represents the number of the outer encoded bits, and C and D represent preset constants, respectively.

4. The transmitter of claim 3 , wherein when the calculated number of the bits to be repeated is equal to or less than the number of the parity bits, the repeater is configured to select bits as many as the calculated number from a first bit of the parity bits and append the selected bits to the input bits.

5. The transmitter of claim 3 , wherein when the calculated number of the bits to be repeated is greater than the number of the parity bits, the repeater is configured to select all the parity bits and append the selected parity bits to the input bits, and additionally select bits as many as a number obtained by subtracting the number of the parity bits from the calculated number of bits to be repeated from a first bit of the parity bits and append the additionally selected bits to the append parity bits.

6. The transmitter of claim 1 , wherein the puncturer is configured to puncture the one or more bits of the parity bits from a last bit of the parity bits.

7. A repetition method of a transmitter, comprising:

encoding input bits comprising zero bits to generate parity bits;

appending one or more bits of a Low Density Parity Check (LDPC) codeword comprising the input bits and the parity bits to the input bits, the one or more bits of the LDPC codeword being repeated; and

puncturing the one or more bits of the parity bits, and

wherein a number of bits to be repeated is determined based on a number of bits other than the zero bits in the input bits.

8. The method of claim 7 , wherein the input bits comprise outer encoded bits, and the appending calculates the number of bits to be repeated based on a number of the outer encoded bits.

9. The method of claim 8 , wherein the appending calculates the number of the bits to be repeated based on a following equation:

N repeat =2×└ C×N outer ┘+D,

where N repeat represents the number of the bits to be repeated, N outer represents the number of the outer encoded bits, and C and D represent preset constants, respectively.

10. The method of claim 9 , wherein when the calculated number of the bits to be repeated is equal to or less than the number of the parity bits, the appending selects bits as many as the calculated number from a first bit of the parity bits and appends the selected bits to the input bits.

11. The method of claim 9 , wherein when the calculated number of the bits to be repeated is greater than the number of the parity bits, the appending selects all the parity bits and appends the selected parity bits to the input bits, and additionally selects bits as many as a number obtained by subtracting the number of the parity bits from the calculated number of bits to be repeated from a first bit of the parity bits and appends the additionally selected bits to the append parity bits.

12. The method of claim 7 , wherein the puncturing punctures the one or more bits of the parity bits from a last bit of the parity bits.