Receiving apparatus and de-interleaving method thereof
A transmitting apparatus and a receiving apparatus are provided. The transmitting apparatus includes: an encoder configured to generate a low density parity check (LDPC) codeword by LDPC encoding based on a parity check matrix; an interleaver configured to interleave the LDPC codeword; and a modulator configured to map the interleaved LDPC codeword onto a modulation symbol, wherein the modulator is further configured to map a bit included in a predetermined bit group from among a plurality of bit groups constituting the LDPC codeword onto a predetermined bit of the modulation symbol.
1. A broadcast signal receiving apparatus comprising:
a receiver configured to receive a broadcast signal from a broadcast signal transmitting apparatus;
a demodulator configured to demodulate the broadcast signal to generate values based on quadrature phase shift keying (QPSK) modulation;
a deinterleaver configured to deinterleave the values, split the deinterleaved values into a plurality of groups, and deinterleave the plurality of groups; and
a decoder configured to decode values of the deinterleaved plurality of groups 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,
wherein the plurality of groups are deinterleaved based on a following equation:
Y π( j )= Xj for (0≤ j<N group ),
where Xj is a j-th group among the plurality of groups, Yj is a j-th group among the deinterleaved plurality of groups, Ngroup is a number of the plurality of groups and π(j) denotes an interleaving order for the deinterleaving, and
wherein the π(j) is represented as follows:
Order of deinterleaving
π(j) (0 ≤ j < 45)
Code
j
0
1
2
3
4
5
6
7
Rate
23
24
25
26
27
28
29
30
5/15
π(j)
35
7
29
11
14
32
38
28
5
13
34
37
23
15
36
18
Order of deinterleaving
π(j) (0 ≤ j < 45)
Code
j
8
9
10
11
12
13
14
15
Rate
31
32
33
34
35
36
37
38
5/15
π(j)
20
17
25
39
19
4
1
12
42
16
33
31
27
22
3
6
Order of deinterleaving
π(j) (0 ≤ j < 45)
Code
j
16
17
18
19
20
21
22
Rate
39
40
41
42
43
44
5/15
π(j)
10
30
0
44
43
2
21
40
24
41
9
26
8.
2. The broadcast signal receiving apparatus of claim 1 , wherein each of the plurality of groups comprises 360 values.
3. The broadcast signal receiving apparatus of claim 1 , wherein π(j) is determined based on at least one of the code length, a modulation method and the code rate.
4. A broadcast signal transmitting apparatus comprising:
an encoder configured to encode input bits to generate parity 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;
an interleaver configured to split a codeword comprising the input bits and the parity bits into a plurality of bit groups, interleave the plurality of bit groups, and interleave bits of the interleaved plurality of bit groups;
a mapper configured to map the interleaved bits to constellation points for quadrature phase shift keying (QPSK) modulation; and
a transmitter configured to transmit a broadcast signal which is generated based on the constellation points,
wherein the plurality of bit groups are interleaved based on a following equation:
Y j =X π(j) for (0≤ j<N group ),
where Xj is a j-th bit group among the plurality of bit groups, Yj is a j-th 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 represented as follows:
Order of interleaving
π(j) (0 ≤ j < 45)
Code
j
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
π(j)
35
7
29
11
14
32
38
28
20
17
25
39
19
4
1
12
10
30
0
44
43
2
21
5
13
34
37
23
15
36
18
42
16
33
31
27
22
3
6
40
24
41
9
26
8.
5. The broadcast signal transmitting apparatus of claim 4 , wherein each of the plurality of bit groups comprises 360 bits.