Transmitting apparatus and interleaving method thereof

A transmitting method comprising:

• encoding input bits to generate parity bits based on a low density parity check (LDPC), a code rate of the LDPC code being 13/15 and a code length of the LDPC code being 16200 bits;
• interleaving the parity bits;
• splitting a codeword comprising the input bits and the interleaved parity bits into a plurality of bit groups;
• interleaving the plurality of bit groups;
• mapping bits of the interleaved plurality of bit groups onto constellation points for 64-quadrature amplitude modulation (QAM);
• and
• transmitting a signal comprising the constellation points,
• wherein the plurality of bit groups are interleaved based on a following equation:
• Yj=Xπ(j) for (0≤j<Ngroup),
• where Xj is a jth bit group among the plurality of bit groups, Yj is a jth bit group among the interleaved plurality of bit groups, Ngroup is a number of the plurality of bit groups, and π(j) denotes an interleaving order for the interleaving, and
• wherein the π(j) is defined as follows:
• Order of the interleaving
• π (j) (0 ≤ j < 45)
• j
• 0
• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 18
• 19
• 20
• 21
• 22
• 23
• 24
• 25
• 26
• 27
• 28
• 29
• 30
• 31
• 32
• 33
• 34
• 35
• 36
• 37
• 38
• 39
• 40
• 41
• 42
• 43
• 44
• π (j)
• 9
• 7
• 15
• 10
• 11
• 12
• 13
• 6
• 21
• 17
• 14
• 20
• 26
• 8
• 25
• 32
• 34
• 23
• 2
• 4
• 31
• 18
• 5
• 27
• 29
• 3
• 38
• 36
• 39
• 43
• 41
• 42
• 40
• 44
• 1
• 28
• 33
• 22
• 16
• 19
• 24
• 0
• 30
• 35
• 37.