Transmitting apparatus and interleaving method thereof

A television (TV) broadcast signal transmitting method comprising:

• generating a codeword comprising input bits and parity bits, wherein the parity bits are generated by encoding the input bits based on a low density parity check (LDPC) code, a code rate of the LDPC code being 5/15 and a code length of the LDPC code being 16200 bits;
• splitting the codeword into a plurality of bit groups;
• interleaving the plurality of bit groups;
• interleaving bits of the interleaved plurality of bit groups;
• demultiplexing the interleaved bits to generate data cells;
• mapping the data cells to constellation points for 256-quadrature amplitude modulation (QAM);
• and
• generating a TV broadcast signal based on the constellation points using orthogonal frequency division multiplexing (OFDM) scheme, and
• transmitting the TV broadcast signal,
• wherein the plurality of bit groups are interleaved based on a following equation:
• Yπ(j)=Xj for (0≤j<Ngroup),
• where Xj is a jth group among the plurality of groups, Yj is a jth group among the deinterleaved plurality of groups, Ngroup is a number of the plurality of bit groups and π(j) denotes a interleaving order for the interleaving, and
• wherein the π(j) is represented as follows:
• Order of the Interleaving
• π(j) (0 ≤ j < 45)
• Code
• 0
• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 18
• 19
• 20
• 21
• 22
• Rate
• 23
• 24
• 25
• 26
• 27
• 28
• 29
• 30
• 31
• 32
• 33
• 34
• 35
• 36
• 37
• 38
• 39
• 40
• 41
• 42
• 43
• 44
• 5/15
• 4
• 23
• 3
• 6
• 18
• 5
• 0
• 2
• 7
• 26
• 21
• 27
• 39
• 42
• 38
• 31
• 1
• 34
• 20
• 37
• 40
• 24
• 43
• 25
• 33
• 9
• 22
• 36
• 30
• 35
• 11
• 10
• 17
• 32
• 13
• 12
• 41
• 15
• 14
• 19
• 16
• 8
• 44
• 29
• 28.