Method and apparatus for encoding and decoding of low density parity check codes
An encoding apparatus is provided. The encoding includes a low density parity check (LDPC) encoder which performs LDPC encoding on input bits based on a parity-check matrix to generate an LDPC codeword formed of 64,800 bits, in which the parity-check matrix includes an information word sub-matrix and a parity sub-matrix, the information word sub-matrix is formed of a group of a plurality of column blocks each including 360 columns, and the parity-check matrix and the information word sub-matrix are defined by various tables which represent positions of value one (1) present in every 360-th column.
1. A television (TV) broadcast signal transmitting apparatus for transmitting TV broadcast data, the transmitting apparatus comprising:
an encoder configured to encode input bits to generate parity bits using a matrix;
an interleaver configured to interleave a codeword using an interleaving order, the codeword comprising the input bits and the parity bits;
a mapper configured to map bits of the interleaved codeword onto constellation points;
a signal generator configured to generate a TV broadcast signal based on the mapped constellation points using orthogonal frequency division multiplexing (OFDM) processing; and
a transmitter configured to transmit the generated TV broadcast signal,
wherein the input bits are based on the TV broadcast data,
wherein the matrix is obtained based on parity indices of a low density parity check (LDPC) code having a code rate being 6/15 and a code length being 64800 bits,
wherein the interleaving order is obtained based on the code rate being 6/15 and the code length being 64800 bits,
wherein the constellation points are determined based on at least one of the code rate being 6/15 or a modulation order for the mapping, and
wherein the parity indices are represented by a table below:
1606 3402 4961 6751 7132 11516 12300 12482 12592 13342 13764
14123 21576 23946 24533 25376 25667 26836 31799 34173 35462
36153 36740 37085 37152 37468 37658
4621 5007 6910 8732 9757 11508 13099 15513 16335 18052 19512
21319 23663 25628 27208 31333 32219 33003 33239 33447
36200 36473 36938 37201 37283 37495 38642
16 1094 2020 3080 4194 5098 5631 6877 7889 8237 9804 10067
11017 11366 13136 13354 15379 18934 20199 24522 26172 28666
30386 32714 36390 37015 37162
700 897 1708 6017 6490 7372 7825 9546 10398 16605 18561 18745
21625 22137 23693 24340 24966 25015 26995 28586 28895 29687
33938 34520 34858 37056 38297
159 2010 2573 3617 4452 4958 5556 5832 6481 8227 9924 10836 14954
15594 16623 18065 19249 22394 22677 23408 23731 24076 24776
27007 28222 30343 38371
3118 3545 4768 4992 5227 6732 8170 9397 10522 11508 15536 20218
21921 28599 29445 29758 29968 31014 32027 33685 34378 35867
36323 36728 36870 38335 38623
1264 4254 6936 9165 9486 9950 10861 11653 13697 13961 15164 15665
18444 19470 20313 21189 24371 26431 26999 28086 28251 29261 31981
34015 35850 36129 37186
111 1307 1628 2041 2524 5358 7988 8191 10322 11905 12919 14127
15515 15711 17061 19024 21195 22902 23727 24401 24608 25111
25228 27338 35398 37794 38196
961 3035 7174 7948 13355 13607 14971 18189 18339 18665 18875
19142 20615 21136 21309 21758 23366 24745 25849 25982 27583
30006 31118 32106 36469 36583 37920
2990 3549 4273 4808 5707 6021 6509 7456 8240 10044 12262
12660 13085 14750 15680 16049 21587 23997 25803 28343 28693
34393 34860 35490 36021 37737 38296
955 4323 5145 6885 8123 9730 11840 12216 19194 20313 23056
24248 24830 25268 26617 26801 28557 29753 30745 31450 31973
32839 33025 33296 35710 37366 37509
264 605 4181 4483 5156 7238 8863 10939 11251 12964 16254
17511 20017 22395 22818 23261 23422 24064 26329 27723 28186
30434 31956 33971 34372 36764 38123
520 2562 2794 3528 3860 4402 5676 6963 8655 9018 9783 11933
16336 17193 17320
19035 20606 23579 23769 24123 24966 27866 32457 34011 34499
36620 37526
10106 10637 10906 34242
1856 15100 19378 21848
943 11191 27806 29411
4575 6359 13629 19383
4476 4953 18782 24313
5441 6381 21840 35943
9638 9763 12546 30120
9587 10626 11047 25700
4088 15298 28768 35047
2332 6363 8782 28863
4625 4933 28298 30289
3541 4918 18257 31746
1221 25233 26757 34892
8150 16677 27934 30021
8500 25016 33043 38070
7374 10207 16189 35811
611 18480 20064 38261
25416 27352 36089 38469
1667 17614 25839 32776
4118 12481 21912 37945
5573 13222 23619 31271
18271 26251 27182 30587
14690 26430 26799 34355
13688 16040 20716 34558
2740 14957 23436 32540
3491 14365 14681 36858
4796 6238 25203 27854
1731 12816 17344 26025
19182 21662 23742 27872
6502 13641 17509 34713
12246 12372 16746 27452
1589 21528 30621 34003
12328 20515 30651 31432
3415 22656 23427 36395
632 5209 25958 31085
619 3690 19648 37778
9528 13581 26965 36447
2147 26249 26968 28776
15698 18209 30683
1132 19888 34111
4608 25513 38874
475 1729 34100
7348 32277 38587
182 16473 33082
3865 9678 21265
4447 20151 27618
6335 14371 38711
704 9695 28858
4856 9757 30546
1993 19361 30732
756 28000 29138
3821 24076 31813
4611 12326 32291
7628 21515 34995
1246 13294 30068
6466 33233 35865
14484 23274 38150
21269 36411 37450
23129 26195 37653.
2. The TV broadcast signal transmitting apparatus of claim 1 , wherein the matrix has a cyclic structure.
3. The TV broadcast signal transmitting apparatus of claim 1 , wherein a predetermined number which is differently set according to the code rate and the code length is 108 when the code rate is 6/15 and the code length is 64800 bits.
4. The TV broadcast signal transmitting apparatus of claim 1 , wherein the parity bits are generated by initiating parity bits, accumulating the input bits to the initiated parity bits based on the matrix, and performing a bit operation based on an accumulated parity bit of a parity index x and an accumulated parity bit of a parity index x−1 to output an parity bit of the parity index x,
where x is a value among values which are greater than 0 and are less than a number of parity bits.
5. The TV broadcast signal transmitting apparatus of claim 4 , wherein the matrix is represented by q(i,j, l) generated based on a following relationship:
q ( i,j, 1)= q ( i,j, 0)+ Q ldpc× 1 (mod M inner ) for 0<1<360
where Q ldpc is a coding parameter determined by the code rate of the LDPC code and the code length of the LDPC code, Minner is the number of parity bits, q(i,j,0) is a parity index represented by a j-th entry in an i-th row of the table, i indicates an index of a row in the table, and j indicates an index of an entry in the row.
6. The TV broadcast signal transmitting apparatus of claim 5 , wherein the input bits are accumulated to the initialized parity bits based on a following relationship,
P q(i, w(i), l) =P q(i, w(i), l) +S k ,
where s k indicates k-th input bit from among the input bits, p q(i, w(i), l) indicates q(i, w(i), l)-th parity bit from among the initialized parity bits, k is a value among values which are greater than or equal to 0 and are less than a number of the input bits, i=└k/360┘1=k (mod 360), and w(i)=j.