CA2940011C

CA2940011C - Transmitting apparatus and interleaving method thereof

Info

Publication number: CA2940011C
Application number: CA2940011A
Authority: CA
Inventors: Se-Ho Myung; Hong-Sil Jeong; Kyung-Joong Kim
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2014-02-19
Filing date: 2015-02-23
Publication date: 2019-06-11
Anticipated expiration: 2035-02-23
Also published as: MX366541B; CA3040604A1; KR101800409B1; KR20170129668A; KR20190064556A; KR102245527B1; MX2019008372A; CA2940011A1; CA3040604C; KR20150098226A; MX2016010774A; CA3133553A1; KR20190011795A; CN106471782B; KR101944526B1; KR101986778B1; CN106471782A; CA3133553C

Abstract

A transmitting apparatus is 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.

Description

[DESCRIPTION]
[Invention Title]
TRANSMITTING APPARATUS AND INTERLEAVING METHOD THEREOF
[Technical Field]
Apparatuses and methods consistent with exemplary embodiments relate to a transmitting apparatus and an interleaving method thereof, and more particularly, to a transmitting apparatus which processes and transmits data, and an interleaving method thereof.
[Background Art]
In the 21st century information-oriented society, broadcasting communication services are moving into the era of digitalization, multi-channel, wideband, and high quality. In particular, as high quality digital televisions, portable multimedia players and portable broadcasting equipment are increasingly used in recent years, there is an increasing demand for methods for supporting various receiving methods of digital broadcasting services.
In order to meet such demand, standard groups are establishing various standards and are providing a variety of services to satisfy users' needs. Therefore, there is a need for a method for providing improved services to users with high decoding and receiving performance.
[Disclosure]
[Technical Problem]
Exemplary embodiments of the inventive concept may overcome the above disadvantages and other disadvantages not described above. However, it is understood that the exemplary embodiment are not required to overcome the disadvantages described above, and may not overcome any of the problems described above.
The exemplary embodiments provide a transmitting apparatus which can map a bit included in a predetermined bit group from among a plurality of bit groups of a low density parity check (LDPC) codeword onto a predetermined bit of a modulation symbol, and transmit the bit, and an interleaving method thereof.
[Technical Solution]
According =to an aspect of an exemplary embodiment, there is provided a transmitting apparatus incluidng: an encoder configured to generate an LDPC codeword by LDPC encoding

2 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.
Each of the plurality of bit groups may be formed of M number of bits. M may be a common divisor of NUN and &ape and may be determined to satisfy Q1dpc=(1\11dpc-K1dpc)/M. In this case, Qidpc may be a cyclic shift parameter value regarding columns in a column group of an information word submatrix of the parity check matrix, Nidpc may be a length of the LDPC
codeword, and Kidp, may be a length of information word bits of the LDPC
codeword.
The interleaver may include: a parity interleaver configured to interleave parity bits of the LDPC codeword; a group interleaver configured to divide the parity-interleaved LDPC
codeword by the plurality of bit groups and rearrange an order of the plurality of bit groups in bit group wise; and a block interleaver configured to interleave the plurality of bit groups the order of which is rearranged.
The group interleaver may be configured to rearrange the order of the plurality of bit groups in bit group wise by using the following equation:
=X)(0 j < Nrour ) where Xj is a jth bit group before the plurality of bit groups are interleaved, Yj is a jth bit group after the plurality of bit groups are interleaved, Ngroup is a total number of the plurality of bit groups, and N(j) is a parameter indicating an interleaving order.
Here, it(j) may be determined based on at least one of a length of the LDPC
codeword, a modulation method, and a code rate.
When the LDPC codeword has a length of 64800, the modulation method is 16-QAM, and the code rate is 6/15, n(j) may be defined as in table 11.
When the LDPC codeword has a length of 64800, the modulation method is 16-QAM, and the code rate is 10/15, n(j) may be defined as in table 14.
When the LDPC codeword has a length of 64800, the modulation method is 16-QAM, and the code rate is 12/15, Ic(j) may be defined as in table 15.
When the LDPC codeword has a length of 64800, the modulation method is 64-QAM, and the code rate is 6/15, n(j) may be defined as in table 17.

3 When the LDPC codeword has a length of 64800, the modulation method is 64-QAM, and the code rate is 8/15, 7r(j) may be defined as in table 18.
When the LDPC codeword has a length of 64800, the modulation method is 64-QAM, and the code rate is 12/15, 7r(j) may be defined as in table 21.
The block interleaver may be configured to interleave by writing the plurality of bit groups in each of a plurality of columns in bit group wise in a column direction, and reading each row of the plurality of columns in which the plurality of bit groups are written in bit group wise in a row direction.
The block interleaver may be configured to serially write, in the plurality of columns, at least some bit groups which are writable in the plurality of columns in bit group wise from among the plurality of bit groups, and then divide and write the other bit groups in an area which remains after the at least some bit groups are written in the plurality of columns in bit group wise.
According to an aspect of another exemplary embodiment, there is provided an interleaving method of a transmitting apparatus, including: generating an LDPC codeword by LDPC
encoding based on a parity check matrix; interleaving the LDPC codeword; and mapping the interleaved LDPC codeword onto a modulation symbol, wherein the mapping comprises mapping 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.
Each of the plurality of bit groups may be formed of M number of bits, and M
may be a common divisor of Nidpc and Kid and may be determined to satisfy Qmpc=(Nbipc-Kidpc)/M. In this case, Qidpc may be a cyclic shift parameter value regarding columns in a column group of an information word submatrix of the parity check matrix, Nidp, may be a length of the LDPC
codeword, and Kid may be a length of information word bits of the LDPC
codeword.
The interleaving may include: interleaving parity bits of the LDPC codeword;
dividing the parity-interleaved LDPC codeword by the plurality of bit groups and rearranging an order of the plurality of bit groups in bit group wise; and interleaving the plurality of bit groups the order of which is rearranged.
The rearranging in bit group wise may include rearranging the order of the plurality of bit groups in bit group wise by using the following equation:
171 =X( J)(0 j < N
group where Xj is a jth bit group before the plurality of bit groups are interleaved, Yi is a ith bit group

4 after the plurality of bit groups are interleaved, Ngroup is a total number of the plurality of bit groups, and ir(j) is a parameter indicating an interleaving order.
Here, 7r(j) may be determined based on at least one of a length of the LDPC
codeword, a modulation method, and a code rate.
When the LDPC codeword has a length of 64800, the modulation method is 16-QAM, and the code rate is 6/15, 7r(j) may be defined as in table 11.
When the LDPC codeword has a length of 64800, the modulation method is 16-QAM, and the code rate is 10/15, m(j) may be defined as in table 14.
When the LDPC codeword has a length of 64800, the modulation method is 16-QAM, and the code rate is 12/15, 7r(j) may be defined as in table 15.
When the LDPC codeword has a length of 64800, the modulation method is 64-QAM, and the code rate is 6/15, m(j) may be defined as in table 17.
When the LDPC codeword has a length of 64800, the modulation method is 64-QAM, and the code rate is 8/15, it(j) may be defined as in table 18.
When the LDPC codeword has a length of 64800, the modulation method is 64-QAM, and the code rate is 12/15, rr(j) may be defined as in table 21.
The interleaving the plurality of bit groups may include interleaving by writing the plurality of bit groups in each of a plurality of columns in bit group wise in a column direction, and reading each row of the plurality of columns in which the plurality of bit groups are written in bit group wise in a row direction.
The interleaving the plurality of bit groups may include serially writing, in the plurality of columns, at least some bit groups which are writable in the plurality of columns in bit group wise from among the plurality of bit groups, and then dividing and writing the other bit groups in an area which remains after the at least some bit groups are written in the plurality of columns in bit group wise.
According to an embodiment, there is provided a transmitting apparatus comprising: an encoder configured to encode input bits to generate parity bits based on a low density parity check (LDPC) code according to a code rate of 6/15 and a code length of 64800;
an interleaver configured to interleave the parity bits, split a codeword into a plurality of bit groups, and interleave the plurality of bit groups to provide an interleaved codeword, wherein the codeword comprising the input bits and the interleaved parity bits; and a mapper configured to map bits of the interleaved codeword onto constellation points for 16-quadrature amplitude 4a modulation(QAM), wherein the plurality of bit groups are interleaved based on a following Y = X,r0) for =th equation: (0 j < Ng'""P) , where Xj is a 3 bit group among the plurality of bit groups, Yj is a =th bit group among the interleaved plurality of bit groups, Ngroup is a total number of the plurality of bit groups, and n(j) denotes a permutation order for the interleaving of the plurality of bit groups, and wherein the z(j) is defined as follows:
Order of interleaving n(j) (0 j <180) Code Rate 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 0) 62 61 64 65 66 07 66 6/15 7r(i) [Advantageous Effects]
According to various exemplary embodiments, improved decoding and receiving performance can be provided.
[Description of Drawings]
The above and/or other aspects will be more apparent by describing in detail exemplary embodiments, with reference to the accompanying drawings, in which:

FIG. 1 is a block diagram to illustrate a configuration of a transmitting apparatus, according to an exemplary embodiment;
FIGs. 2 to 4 are views to illustrate a configuration of a parity check matrix, according to exemplary embodiments;
FIG. 5 is a block diagram to illustrate a configuration of an interleaver, according to an exemplary embodiment;
FIGs. 6 to 8 are views to illustrate an interleaving method, according to exemplary embodiments;
FIGs. 9 to 14 are views to illustrate an interleaving method of a block interleaver, according to exemplary embodiments;
FIG. 15 is a view to illustrate an operation of a demultiplexer, according to an exemplary embodiment;
FIGs. 16 and 17 are views to illustrate a method for designing an interleaving pattern, according to exemplary embodiments;
FIG. 18 is a block diagram to illustrate a configuration of a receiving apparatus according to an exemplary embodiment;
FIG. 19 is a block diagram to illustrate a configuration of a deinterleaver, according to an exemplary embodiment;
FIG. 20 is a view to illustrate a deinterleaving method of a block deinterleaver, according to an exemplary embodiment; and FIG. 21 is a flowchart to illustrate an interleaving method, according to an exemplary embodiment.
[Mode for Invention]
Hereinafter, various exemplary embodiments will be described in greater detail with reference to the accompanying drawings.
In the following description, same reference numerals are used for the same elements when they are depicted in different drawings. The matters defined in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of the exemplary embodiments. Thus, it is apparent that the exemplary embodiments can be carried out without those specifically defined matters. Also, functions or elements known in the related art are not described in detail since they would obscure the exemplary embodiments with unnecessary detail.
FIG. 1 is a block diagram to illustrate a configuration of a transmitting apparatus according to an exemplary embodiment. Referring to FIG. 1, the transmitting apparatus 100 includes an encoder 110, an interleaver 120, and a modulator 130 (or a constellation mapper).
The encoder 110 generates a low density parity check (LDPC) codeword by performing LDPC encoding based on a parity check matrix. To achieve this, the encoder 110 may include an LDPC encoder (not shown) to perform the LDPC encoding.
Specifically, the encoder 110 LDPC-encodes information word(or information) bits to generate the LDPC codeword which is formed of information word bits and parity bits (that is, LDPC parity bits). Here, bits input to the encoder 110 may be used as the information word bits.
Also, since an LDPC code is a systematic code, the information word bits may be included in the LDPC codeword as they are.
The LDPC codeword is formed of the information word bits and the parity bits.
For example, the LDPC codeword is formed of Nidp, number of bits, and includes Ickipc number of information word bits and Nparity=N1dpc-K1dpc number of parity bits.
In this case, the encoder 110 may generate the LDPC codeword by performing the LDPC
encoding based on the parity check matrix. That is, since the LDPC encoding is a process for generating an LDPC codeword to satisfy II- CT=0, the encoder 110 may use the parity check matrix when performing the LDPC encoding. Herein, H is a parity check matrix and C is an LDPC codeword.
For the LDPC encoding, the transmitting apparatus 100 may include a memory and may pre-store parity check matrices of various formats.
For example, the transmitting apparatus 100 may pre-store parity check matrices which are defined in Digital Video Broadcasting-Cable version 2 (DVB-C2), Digital Video Broadcasting-Satellite-Second Generation (DVB-S2), Digital Video Broadcasting-Second Generation Terrestrial (DVB-T2), etc., or may pre-store parity check matrices which are defined in the North America digital broadcasting standard system Advanced Television System Committee (ATSC) 3.0 standards, which are currently being established. However, this is merely an example and the transmitting apparatus 100 may pre-store parity check matrices of other formats in addition to these parity check matrices.
Hereinafter, a parity check matrix according to various exemplary embodiments will be explained in detail with reference to the drawings. In the parity check matrix, elements other than elements having 1 have 0.
For example, the parity check matrix according to an exemplary embodiment may have a configuration of FIG. 2.
Referring to FIG. 2, a parity check matrix 200 is formed of an information word submatrix(or an information submatrix) 210 corresponding to information word bits, and a parity submatrix 220 corresponding to parity bits.
The information word submatrix 210 includes Kkipc number of columns and the parity submatrix 220 includes Nparity=Nidpc-Kidpc number of columns. The number of rows of the parity check matrix 200 is identical to the number of columns of the parity submatrix 220, Nparity=N1d13c"
Kldpc=
In addition, in the parity check matrix 200, NIdpc is a length of an LDPC
codeword, Kldpc is a length of information word bits, and Nparity=Nidpc-Kidpc is a length of parity bits. The length of the LDPC codeword, the information word bits, and the parity bits mean the number of bits included in each of the LDPC codeword, the information word bits, and the parity bits.
Hereinafter, the configuration of the information word submatrix 210 and the parity submatrix 220 will be explained in detail.
The information word submatrix 210 includes Kid number of columns (that is, 0th column to (lcdpc-1)th column), and follows the following rules:
First, M number of columns from among Kid number of columns of the information word submatrix 210 belong to the same group, and Kid number of columns is divided into Kkipc/M
number of column groups. In each column group, a column is cyclic-shifted from an immediately previous column by Qldpc. That is, Qicipc may be a cyclic shift parameter value regarding columns in a column group of the information word submatrix 210 of the parity check matrix 200.
Herein, M is an interval at which a pattern of a column group, which includes a plurality of columns, is repeated in the information word submatrix 210 (e.g., M=360), and Qicipc is a size by which one column is cyclic-shifted from an immediately previous column in a same column group in the information word submatrix 210. Also, M is a common divisor of I=1Idp, and Kid and is determined to satisfy Qtapc=(Ntapc-Kidpc)/M. Here, M and Qmpc are integers and Kidpc/M is also an integer. M and Qtdp, may have various values according to a length of the LDPC codeword and a code rate (CR)(or, coding rate).
For example, when M=360 and the length of the LDPC codeword, Nidpc, is 64800, Qidpc may be defined as in table 1 presented below, and, when M=360 and the length I=Tidpc of the LDPC
codeword is 16200, Qmp, may be defined as in table 2 presented below.
[Table 1]
Code Rate Nidpc M Qldpc

5/15 64800 360 120

6/15 64800 360 108

7/15 64800 360 96

8/15 64800 360 84

9/15 64800 360 72

10/15 64800 360 60

11/15 64800 360 48

12/15 64800 360 36

13/15 64800 360 24 [Table 2]
Code Rate NIdoc M Qldpc Second, when the degree of the 0th column of the ith column group (i=0, 1, ..., Kidpc/M-1) is D, (herein, the degree is the number of value 1 existing in each column and all columns belonging to the same column group have the same degree), and a position (or an index) of each row where 1 exists in the 0th column of the ith column group is RP0),R,(1c)õ- = =,Ri(Do'-') , an index Ri(kj) of a row where kth 1 is located in the jth column in the ith column group is determined by following Equation 1:
kkj) =k4()1_1) + a/pc mod(NidPc ¨K ) idPc ... (1), where k=0, 1,2, ...D1-1; i=0, 1, ..., K1dpc/M-1; and j=1, 2, ..., M-1.
Equation 1 can be expressed as following Equation 2:

IC ¨irko) + jmodM)x adpc} mod(Nktp, ¨ Kidpc) . . . (2), where k=0, 1,2, ...Di-1; 1=0, 1, ..., K1dpe/M-1; and j=1, 2, ..., M-1. Since j=1, 2, ..., M-1, (j mod M) of Equation 2 may be regarded as j.
In the above equations, Ri(ki) is an index of a row where le 1 is located in the ith column in the -th column group, NIdpc is a length of an LDPC codeword, Kidpc is a length of information word bits, Di is a degree of columns belonging to the ith column group, M is the number of columns belonging to a single column group, and Qldpc is a size by which each column in the column group is cyclic-shifted.
As a result, referring to these equations, when only Ri(,k0) is known, the index Ri(kj) of the row where the kth 1 is located in the jth column in the ith column group can be known. Therefore, when the index value of the row where the kth 1 is located in the 0th column of each column group is stored, a position of column and row where 1 is located in the parity check matrix 200 having the configuration of FIG. 2 (that is, in the information word submatrix 210 of the parity check matrix 200) can be known.
According to the above-described rules, all of the columns belonging to the ith column group have the same degree Di. Accordingly, the LDPC codeword which stores information on the parity check matrix according to the above-described rules may be briefly expressed as follows.
For example, when Nidpc is 30, Kldpc is 15, and Qicipc is 3, position information of the row where 1 is located in the Oth column of the three column groups may be expressed by a sequence of Equations 3 and may be referred to as "weight-1 position sequence".
R1( =1, R20) = 2, R1(30) = 8,R1(40) = 10, 1:41)0 ¨0, M.2?) ¨9, R = 13, = = 14.
(3), where Ri(kj) is an index of a row where kth 1 is located in the ith column in the ith column group.
The weight-1 position sequence like Equation 3 which expresses an index of a row where 1 is located in the Oth column of each column group may be briefly expressed as in Table 3 presented below:
[Table 3]

. 014 Table 3 shows positions of elements having value 1 in the parity check matrix, and the ith weight-1 position sequence is expressed by indexes of rows where 1 is located in the Oth column belonging to the ith column group.
The information word submatrix 210 of the parity check matrix according to an exemplary embodiment may be defined as in Tables 4 to 8 presented below, based on the above descriptions.
Specifically, Tables 4 to 8 show indexes of rows where 1 is located in the 0th column of the ith column group of the information word submatrix 210. That is, the information word submatrix 210 is formed of a plurality of column groups each including M number of columns, and positions of 1 in the Oth column of each of the plurality of column groups may be defined by Tables 4 to 8.
Herein, the indexes of the rows where 1 is located in the 0th column of the ith column group mean "addresses of parity bit accumulators". The "addresses of parity bit accumulators" have the same meaning as defined in the DVB-C2/S2/T2 standards or the ATSC 3.0 standards which are currently being established, and thus, a detailed explanation thereof is omitted.
For example, when the length Nicipc of the LDPC codeword is 64800, the code rate is 6/15, and M is 360, the indexes of the rows where 1 is located in the Oth column of the ith column group of the information word submatrix 210 are as shown in Table 4 presented below:
[Table 4]

i Index Of row where 1 is lacatecii cotiiiim Of ifililth,Tafuom group.
_ . õ

1 4621 5007 5910 5732 9757 11.508 13099 15513 26335 18052 19512 21319 2366325628.27208 31333 32219 33003 33239 33447 - - .

,296137 3'3638 3452034358 37056 38297 6 1264 4254 6936 9165 9486 9950 10861 11653 1.3697 13961 15164 15665 18444 7 = 111 1307 1628 2041. 1524 5353 7988 8191 16122 11905 12919 14127 15515 15711. 17061 19024 21195 12902 8727 24401 27583 30006 31118, 3210636460 i6sea 37920 14750 15680 16049 21587 23097 25.303 26343 955 4323 51.45 6835 8123 9730 11840 12216 19134 20313 23056 24148 24830 25268 27866 32457 34011 34499 36620 37526 _

14 1856 15100 19378 21348 , 943 11191 2780629411 _ . õ.

18 5441. 6381 21840 35943 .9587 W626 11047 25700 ! 21 4088 15298 28768 35047 22 2332 6363 8782 26863 .

34 18.271 26251 27182 30587 44 1589 21$28 30621 34003 In another example, when the length Nidp, of the LDPC codeword is 64800, the code rate is 8/15, and M is 360, the indexes of the rows where 1 is located in the Oth column of the ith column group of the information word submatrix 210 are as shown in Table 5 presented below:
[Table 5]

Index of row where 1 is located in the 0th column of the ith column group = 0 2768 3039 4059 58566245 7013 8157 9341 9302 10470 11521 12083 16610 13361 20321 24601 27420 23206.29788 1989422043 22784 27383 23615 28804.

6 389 2248 5$40 6043 7000 9054 11075 1176012217 12565 13587 1540$ 19422 .7 1015 2002 5764 6777 93469629 11039 11153 12690 13068 13990 1,6841. 17702 20021. 24106 26300 29332 30081 30196 8 ' 1430 30843467 4401 4798 5187 7851 11368 12323 14325 14546 16360 17158 196091971.7 22150 24941 27908 29018 11 -! $S8 171-81 2311 5511 72189107.10454 12252 13662 1571.415894 17025_18671 243_04 25316 25556 28439 28977 29212 12 1047 1494 1713 4645 5030 6811 7868 8146 10611 1.5767'1782 18191.
22614.23021. 23763 25478: 26491,29088' 29757 13 I 59 1781 1900 38144121 8044.39069175 11156 14841 15789 160-33 16755 14 1 1957 3057 4399 9476 10171 10769 11335 11569 15002 19501 20621 22642.
234$2 24360 23109 252902823 28505 29122 I 2395 3070 3437 4764 4905 6670 9244 11845 13352 13573 1397$ 14600 15871 17996 18 I 5229 6235 7134 7655 9139 13527 15408 1.6058 16705 18320 19909 20901 22238 22437 2365425131 2755028247 29903 .

I 7103 10069 201,11 22850 , 26 4285 15413 26448 29069 : 29 3942 17248 19486 27922 ao 8668 10230 16922 26678 = 31 6158 9980 13788 28198 = 32 12422 16076 24206 29887 ! 33 8778 10649 18747 22111 = 34. 21029 22677 27150 28980. .

as 24016 25880 26268 = 43 2343 8382 28840 44 3907 18374.26939 = 45 1132 1.290 $786 =

49. 12697 13407 22178 12788 21227 22894', 51 629 2854 6232, 52. 2289 18227 27458 = 53 7593 21935 230011 54.- 3836 7081, 12282 . 60 195642062925186 68 _13227 33035 24450 72 12.518 17374 24267 73. 1222 11859 27922 SO 6374 17343 21%9 8$ 20913 29473 30103 In another example, when the length Num of the LDPC codeword is 64800, the code rate is 10/15, and M is 360, the indexes of rows where 1 exists in the 0th column of the ith column group of the information word submatrix 210 are defined as shown in Table 6 below.
[Table 6]

Index of row where I is located in the 0th column of the ith column group x7sag17990 .j. 2559 4025'5344 5510 9167 9728 11112 1485917104 17721 18900 1379129079 ^ 24082929 3630 4357 5851 73298536 8695 10603 11003 14304 14937 15767 18402 a M2 870 209525855517 4196 6767 7311 73651.3046 16-35415576 2054921424 9 935 1591 5248 3509 3706 3)547617452767864 90331361815675 154453.83ss 10 975 377440133 sals 6166 7218 76339657,20203 1052'14740 1732018126 19544 1.1 1795 2005 21441418 61489051 64169 9728.10575 16/921-1111 13171 179i3 1.2 197 3151824 2325 2640 2E68 5070 5597 7016 8109 9935 12608 16142 17912 14 1.19 3485-15041 6624 93.311404 66969.059 9246-115.7014336198g 189411-92te 215as

15 228 1999 1967 229930/1 5074 447595758,99341024410697116911230221418.

16 13301579 1739 2.234 3701 386557136677 7263 112721214512765 17121 20011

17 3031658 2501 492557785985 96351014010820 11779 118491205815650 20426

18 698 2434 5071 311940544125 56635949 6928 7086 8034 12173 '15280174519392' r, 19 2321613 3040 49017435 5135 91173139 10131 11321 17947 17435 15153 18556 10 1/372/ 6254 5509 78808139 1043712252 13929 140$S'14149130$2 15694 22 = 1291 2500 4209 4312 3099-9194 1001413ms 23256 13972 11409 /An 3 15214 . 25 6785 11950214.55 22_ 5976 1193=1 20395, = 11, 5230=11459 119997 32 5809 15779 20574, 33 2520 17835 18533' 1015 9542 9931, õ 35 3728 5337 12142' , , 25106666 9166 37 12892,15307 20911 ' = 19 1075 2497 12563 41.
ssss 15547 16839.
, ¨42 8384 1933819266 44 4880 10431 12208' 291011895 12642' '47 '4541 7905 14994 , 48 4564 6714 7378 49 4639 3651 18871*
,,.50_ 1578718948 20246 .52 nqi. lion 14640 .55 1737 6519 101$1 .54 1039415107171073 55 1.8287i045 12974 56 nos 1605817903 57 . t1139 15717 17764 5&231t23 14516 59 . I 11039 20390.20924 1_551 1163'17411 , N?.46 9557 6552 62 , I 2E90 1093G 14756 i 9011 ii124 21517 64 :1529.12955.15102 65 I 419.6750173.5.

70 ;' 1244 5177 6015 72 L47E739/%2264 75 34568931120Th 74 r-15342 11271.20952 -75 I 51.19 159.52 13711 II 7031 7626.11031 '79 3539 7111 16S75 _ . . .
10 46E1212891 1.5792 11 4.884 7959 1435 , ! 22l04747311 õ .õ
I .5795 1,0821 11514 .16 15939 18316 11941 = 17 1786 8057 21566 As 2212 13259-16432 139 46253U8W900.

Si 145241275121.226 .12 I ,5989 11111 '12441 93 8182 10719 1.6350 94 653Ã1765113100 = 96. 228311907 17567 -11 = I. 654014121.15175

19 I 1177 120,35 14901 19 , 1136 6458 11311 - 101 1 5949-91A8.12809 .õ

102 1710 134.6 112.44 103, i 7384.1213111989 104 1461'1139S 20999 05 1943 1045133.5k17 ids 5005815510E135 fat 17750 SS B29331513 to& 47258041,10112 31337:162645 VMS
III 14349 Va61,_17513 2522 10813 1,6157 %FM Ni4tAti ti4'7114412S 1E75.3:

Ils 160 R045 15525 U? 14112 13724167913 , _ 113 4291 ,7(1,42 181741 Lisr 594519$79 20721 In another example, when the length Nidp, of the LDPC codeword is 64800, the code rate is 10/15, and M is 360, the indexes of rows where 1 exists in the 0th column of the lth column group of the information word submatrix 210 are defined as shown in Table 7 below.
[Table 7]

i Index of row where 1 is located in the 0th column of the ith column group 13 1663 3247 5003 5760 7186 7360 10346 14211.14717 14792 15155 16128 17355 5009 5632 6531 9430 9886 10621 11765.13969 16178 16413 18110 18249 20616 20759 2.3 1631 3121 3994 5005 7810 8850 10315 10589 13407 17162 18624 18758 19311 24 736 2424 4792.5600 6370 10061 16053 16775 18600 1254 8163 8876,9.157 12141 14587 16545 17,1,75.18191 48 1018 1023.1 17720 5781 11588,18888 55. 9568 10122 15945 89: 5583 9768 10333 = 93 8477 15970 18488 In another example, when the length Nidpc of the LDPC codeword is 64800, the code rate is 12/15, and M is 360, the indexes of rows where 1 exists in the 0 column of the ith column group of the information word submatrix 210 are defined as shown in Table 8 below.
[Table 8]

i I Index of row where 1 is located in the 0th column of the 'ith column group . _ 0 5341472 1521 1357.3338 3358'3723 4185 5126 5889 7737 8632 8940 9725 1 2.21 445 590 3779 3835 6929 7743 8280 8448 8451 9367 10042 11242:12917 2 44524837 49005029 6449 6587 6751 3684 9935 11681 11811 11885 12089,12909, 3 2418 1018 3647 4210 4471 7447 7502 9490 10067 1/092 1/139 /1255 12203.

4 2591 2947 3349:3406.44174519 5176 6672 8498 8863 9201 11294 11375 12134 27 /01 197 290 871-1727 3911 5411 6676 601 9350'10310'10798'12439 7 2193 1740 4808 5217 5660 6375 6787 8219 8466 9037 10353 10581 11118 /2762.
.8 731594 2146 2715 3501 3572 3639 3725 6959 7287 8406 10120 18507 10691.
9 240 732 1215 2165 2738 2830 3439 3881 4197 4991.6429 7061 9756 10451 3;0 831 1568 2828.3424 4319 4516 4639 6018 9702 10203 10417 11240 11518 12458:

22 10491215 1651 2325 3493 4353 5750 6483 762.3 8782 9735 9503 11744 11937 13 1193 2060 2289 2964 3478 4992 4758 6709 7162 8231 8126 11140 11908'12243-14 9732220 2439'3338 3850 4559 65675745 9656 970810162 10542 10711 22639 2403 2938 3117.3247 3711 5993 5844 5932 7801 10152 10226 11498 12162 12941 15 3782 2229.2275 2533 3582 3951 5275 5774 7930 9824 10920 11035 12340 22440 17 285 384 1580 2230;3464 3873.555* 86568942 5006 10175 11425.11745 12536 18 155 354 1090 1330 2002 2236, 3539 3705 4922 5958'5575 8554 9972 12760 19 303 876 2059 2142 5244 5330 6644 7576 861.4 9598 /0410 10718 11033 12957 3449 3617-4408 4502 4727 6i82 3335 3928 9372 9544 10237 10747 11455 12747 21 811 2555 2820 8677 8974 963211069'11548 11839 12107 12411 12695 12812 24 .474791 958 3902 4924 4965 5085 5908 5109 5325 7931 9038 9401 15568 13574461 4658 5911 6037 7127,7318 8678 8924 9000 5473 96402 10446 12692 26 1394.7571 12881 27 13931447 7972:
ZS 633 1257 10597' 31 1108 10374 10546' 34 7719 9475 20503:
2997 9418.9561.
35 5777 6510 11229' 481 7229 7543;
, 7865 8289 9804 43 __________________ 6180 7096 9481 47 1852 8.958 11020 50, 2594 9958 12742 ,159 2062 12079 sa W35 8673 12734 1 59 28.4448.21 11:779 66 244 1855 4651.

s 391 16/7 10126 69 "25Q925910603 72 7667 8.875 11451 74¨ 802110184 11656 75 - 572610951:12348 75 32t8 6362 736a 77 1.1137 53581 40. 1980 2219 4569 82 "2803 3314 12808 87 ,1175 47'44 12219 39 '2206 166,26 11151 95 Mot 10755 12780 9e 1028 7958 10825 97 I am 8602 10793 104. 1064 2848 12753 ia3 5504 6/9310171 _ 112 1.263 9585 12912 115 1.051 6188 10038 128 2295 3.540 5610 124, 5177 9586 11143 in 943 3590 11649 135 251.5 5843 9202 138 7870 831.7 10322 141 *1419085 12555 143, 4457,11398 12904 In the above-described examples, the length of the LDPC codeword is 64800 and the code rate is 6/15, 8/15, 10/15, and 12/15. However, this is merely an example and the position of 1 in the information word submatrix 210 may be defined variously when the length of the LDPC
codeword is 16200 or the code rate has different values.
According to an exemplary embodiment, even when the order of numbers in a sequence corresponding to the ith column group of the parity check matrix 200 as shown in the above-described Tables 4 to 8 is changed, the changed parity check matrix is a parity check matrix used for the same code. Therefore, a case in which the order of numbers in the sequence corresponding to the ith column group in Tables 4 to 8 is changed is covered by the inventive concept.
According to an exemplary embodiment, even when the arrangement order of sequences corresponding to each column group is changed in Tables 4 to 8, cycle characteristics on a graph of a code and algebraic characteristics such as degree distribution are not changed. Therefore, a case in which the arrangement order of the sequences shown in Tables 4 to 8 is changed is also covered by the inventive concept.
In addition, even when a multiple of Qidpc is equally added to all sequences corresponding to a certain column group in Tables 4 to 8, the cycle characteristics on the graph of the code or the algebraic characteristics such as degree distribution are not changed.
Therefore, a result of equally adding a multiple of Qmpc to the sequences shown in Tables 4 to 8 is also covered by the inventive concept. However, it should be noted that, when the resulting value obtained by adding the multiple of Qmpc to a given sequence is greater than or equal to (Nidpc-Kidp,), a value obtained by applying a modulo operation for (Nidpc-Kkipc.) to the resulting value should be applied instead.
Once positions of the rows where 1 exists in the Oth column of the ith column group of the information word submatrix 210 are defined as shown in Tables 4 to 8, positions of rows where 1 exists in another column of each column group may be defined since the positions of the rows where 1 exists in the 0th column are cyclic-shifted by Qmpc in the next column.
For example, in the case of Table 4, in the Oth column of the 0th column group of the information word submatrix 210, 1 exists in the 1606th row, 3402nd row, 4961st row.....
In this case, since Okipc=(Nidpc-K1dp,)/M464800-25920)/360.108, the indexes of the rows where 1 is located in the 1st column of the 0th column group may be 1714(.1606+108), 3510(.3402+108), 5069(=4961+108),..., and the indexes of the rows where 1 is located in the 2nd column of the Oth column group may be 1822(=1714+108), 3618(.3510+108), 5177(=5069+108),....

In the above-described method, the indexes of the rows where 1 is located in all rows of each column group may be defined.
The parity submatrix 220 of the parity check matrix 200 shown in FIG. 2 may be defined as follows:
The parity submatrix 220 includes Nidpc-Kidpc number of columns (that is, Kidpcth column to (Nipdc-1)th column), and has a dual diagonal or staircase configuration.
Accordingly, the degree of columns except the last column (that is, (Nidpc-1)th column) from among the columns included in the parity submatrix 220 is 2, and the degree of the last column is 1.
As a result, the information word submatrix 210 of the parity check matrix 200 may be defined by Tables 4 to 8, and the parity submatrix 220 of the parity check matrix 200 may have a dual diagonal configuration.
When the columns and rows of the parity check matrix 200 shown in FIG. 2 are permutated based on Equation 4 and Equation 5, the parity check matrix shown in FIG. 2 may be changed to a parity check matrix 300 shown in FIG. 3.
adpc =i+ = j+i (0 i<M,0 j < Qupc)... (4) Kidpcadpc = k + 1 up, + M = 1 + k (0 k < M ,0 1 < Vdpc) . . . (5) The method for permutating based on Equation 4 and Equation 5 will be explained below.
Since row permutation and column permutation apply the same principle, the row permutation will be explained by the way of an example.
In the case of the row permutation, regarding the Xth row, i and j satisfying X = ,dp,x i + fare calculated and the Xth row is permutated by assigning the calculated i and j to Mx j+i. For example, regarding the 7th row, i and j satisfying 7 = 2 x i + j are 3 and 1, respectively. Therefore, the 7th row is permutated to the 13th row (10 x 1+3 =13 ).
When the row permutation and the column permutation are performed in the above-described method, the parity check matrix of FIG. 2 may be converted into the parity check matrix of FIG.
3.
Referring to FIG. 3, the parity check matrix 300 is divided into a plurality of partial blocks, and a quasi-cyclic matrix of M x M corresponds to each partial block.
Accordingly, the parity check matrix 300 having the configuration of FIG. 3 is formed of matrix units of M x M. That is, the submatrices of M x M are arranged in the plurality of partial blocks, constituting the parity check matrix 300.
Since the parity check matrix 300 is formed of the quasi-cyclic matrices of MxM, M
number of columns may be referred to as a column block and M number of rows may be referred to as a row block. Accordingly, the parity check matrix 300 having the configuration of FIG. 3 is formed of Nqc_cohnim=Nidpc/M number of column blocks and Nqc_row=Nparity/M
number of row blocks.
Hereinafter, the submatrix of M x M will be explained.
First, the (Nqc_columrr1)th column block of the 0th row block has a form shown in Equation 6 presented below:
0 0 ... 0 0 10...00 A = 0 1 ... 00 0 0 ... 1 0 - ... (6) As described above, A 330 is an MxM matrix, values of the 0th row and the (M-1)th column are all "0", and, regarding 0< k(M-2), the (i+1)th row of the ith column is "1" and the other values are "0".
Second, regarding 0<i<(NIapc-Kidp,)/M-1 in the parity submatrix 320, the ith row block of the (Kidpc/M+i)th column block is configured by a unit matrix MM 340. In addition, regarding 0<i<(Nkipc-K1dpc)/M-2, the (i+1)th row block of the (Kidpc/M+i)th column block is configured by a unit matrix fm.m 340.
Third, a block 350 constituting the information word submatrix 310 may have a cyclic-shifted format of a cyclic matrix P. Pau , or an added format of the cyclic-shifted matrix P"u of the cyclic matrix P (or an overlapping format).
For example, a format in which the cyclic matrix P is cyclic-shifted to the right by 1 may be expressed by Equation 7 presented below:

001...0 P=
000...1 - = = = (7) The cyclic matrix P is a square matrix having an M xM size and is a matrix in which a weight of each of M number of rows is 1 and a weight of each of M number of columns is 1.
When aii is 0, the cyclic matrix P, that is, P indicates a unit matrix /m.m , and when is co, 13 is a zero matrix.
A submatrix existing where the ith row block and the ith column block intersect in the parity check matrix 300 of FIG. 3 may be Pau . Accordingly, i and j indicate the number of row blocks and the number of column blocks in the partial blocks corresponding to the information word.
Accordingly, in the parity check matrix 300, the total number of columns is Nidpc=M X Nqc_column, and the total number of rows is Nparity=M Nqe_row= That is, the parity check matrix 300 is formed of Nqc_coiumn number of "column blocks" and Nqc_row number of "row blocks".
Hereinafter, a method for performing LDPC encoding based on the parity check matrix 200 as shown in FIG. 2 will be explained. An LDPC encoding process when the parity check matrix 200 is defined as shown in Table 4 by way of an example will be explained for the convenience of explanation.
First, when information word bits having a length of Kidpc are [io, ir, i2, =
licap,_ib and parity bits having a length of Nid are [po, pi, p2,.= = pc-Kidpc põ1], the LDPC encoding is performed by the following process.
Step 1) Parity bits are initialized as '0'. That is, po= pi= P2'= = ==PN4,-K1=0.
Step 2) The Oth information word bit io is accumulated in a parity bit having the address of the parity bit defined in the first row (that is, the row of i=0) of table 4 as the index of the parity bit.
This may be expressed by Equation 8 presented below:

P1606 = P16060 0 P24533= P24533 0 0 P3402 = P34020 0 P25376= P253760 0 P4961 = P49610 0 P25667= P25667 010 P6751 = P6751 0 0 P26836= P26836 0 0 P7132 = P71320 0 P31799 = P31799 'O
P11516 = P11516 OI 0 P34173 = P34173 0 0 P12300= P12300 0 0 P35462= P35462 0 0 P12482= P12482 Oi 0 P36153 = P361530 0 P12592= P12592iIO P36740 = P36740 0 0 P13342= P13342 0 0 P37085¨ P37085 I0 P13764= P13764 cI 0 P37152 = P37152 0 0 P14123 = P1412301 0 P37468 = P37468 0 0 P21576= P6 i0 P37658 = P37553 I0 ID23946 = P23946 0 0 ...(8) Herein, io is a 0th information word bit, n is an ith parity bit, and is a binary operation.
According to the binary operation, 1 8 1 equals 0, 110 0 equals 1, 0 e 1 equals 1, 0 0 0 equals 0.
Step 3) The other 359 information word bits in, (m=1, 2, ..., 359) are accumulated in the parity bit. The other information word bits may belong to the same column group as that of io. In this case, the address of the parity bit may be determined based on Equation 9 presented below:
(x + (m mod 360) x Qmpc) mo d (Nmp, ¨ Kidp, ) . . . (9) Herein, x is an address of a parity bit accumulator corresponding to the information word bit and Qtdpc is a size by which each column is cyclic-shifted in the information word submatrix, and may be 108 in the case of table 4. In addition, since m=1, 2, ..., 359, (m mod 360) in Equation 9 may be regarded as m.
As a result, information word bits in, (m=1,2,..., 359) are accumulated in the parity bits having the address of the parity bit calculated based on Equation 9 as the index. For example, an operation as shown in Equation 10 presented below may be performed for the information word bit P1714 = P17140 i 1 P24641= P24641 P3510 = P351o0i 1 P25484= P25484 0 i 1 P5069 = P50690 i 1 P25775= P25775 P6859 = P6859@ i 1 P26944= P26944 P7240 = P72400 i 1 P31907= P31907 0 i 1 P11624= P11624 CDI 1 P34281= P34281 P12408= P12408 (D i 1 P35570= P35570 0 i 1 P12590= P12590 CD i 1 P36261= P36261 (Di 1 P12700= P12700 0 i 1 P36848= P36848 i 1 P13450= P13450 0 i 1 P37193= P37193 0 i 1 P13872= P13872 ei 1 P37260= P37260 01 1 P14231= P14231 ei 1 P37576= P37576 0i 1 P21684 = P21684 i 1 P37766= P37766 ei 1 P24054 = P24054 CD i 1 ...(10) Herein, i1 is a 1st information word bit, pi is an ith parity bit, and is a binary operation.
According to the binary operation, 1 1 equals 0, 1 C) 0 equals 1, 0 1 equals 1, 0 0 0 equals 0.
Step 4) The 360th information word bits i360 is accumulated in a parity bit having the address of the parity bit defined in the 2nd row (that is, the row of i=1) of table 4 as the index of the parity bit.
Step 5) The other 359 information word bits belonging to the same group as that of the information word bit i360 are accumulated in the parity bit. In this case, the address of the parity bit may be determined based on Equation 9. However, in this case, x is the address of the parity bit accumulator corresponding to the information word bit i360.
Step 6) Steps 4 and 5 described above are repeated for all of the column groups of table 4.
Step 7) As a result, a parity bit pi is calculated based on Equation 11 presented below. In this case, i is initialized as 1.
Pr = p, p,_,i =1,2,..., Nidp, ¨ Kidp, ¨1 ... (11) In Equation 11, pi is an ith parity bit, Nidpc is a length of an LDPC
codeword, Kid is a length of an information word of the LDPC codeword, and is a binary operation.
As a result, the encoder 110 may calculate the parity bits according to the above-described method.
In another example, a parity check matrix according to an exemplary embodiment may have a configuration as shown in FIG. 4.
Referring to FIG. 4, the parity check matrix 400 may be formed of 5 matrices A, B, C, Z, and D. Hereinafter, the configuration of each matrix will be explained to explain the configuration of the parity check matrix 400.
First, Ml, M2, Ql, and 02, which are parameter values related to the parity check matrix 400 as shown in FIG. 4, may be defined as shown in table 9 presented below according to the length and the code rate of the LDPC codeword.
[Table 9]
sizc$
Rate Length 3/15 16200 1080 11.880 3 33 16200 720 10080= 2 28 The matrix A is formed of K number of columns and g number of rows, and the matrix C is formed of K+g number of columns and N-K-g number of rows. Herein, K is a length of information word bits, and N is a length of the LDPC codeword.
Indexes of rows where 1 is located in the 0th column of the ith column group in the matrix A
and the matrix C may be defined based on table 10 according to the length and the code rate of the LDPC codeword. In this case, an interval at which a pattern of a column is repeated in each of the matrix A and the matrix C, that is, the number of columns belonging to the same group, may be 360.
For example, when the length N of the LDPC codeword is 64800 and the code rate is 6/15, the indexes of rows where 1 is located in the 0th column of the ith column group in the matrix A
and the matrix C are defined as shown in table 10 presented below:
[Table 10]

I Index of row where 1 is located in the Oth column of the ith column group . _ 0 71276856 6867. 12354 17373..18159 26420 2/460. 28477 1 257 322 672.2533 5316 5578 9037 10231 13845 36497 '2 233 765 904 1,366 3875 13145 15409 18620 23910'30825-.3 100 224 405 127761386114787 16781 23886 29099 31419 .4 23496.891 2512 12589 14074 19392-.20339 2765828684:
. 5 473712 759 1215 4574 3838:12551 i38144242: 32728 511567 fi15 11823 1710617900 19338 22315, 24396 26448 ' 7 45733 836 1923 372717458 2.5746 33805 35995 36557 8 17487 575 26703122514518009 n99131673:36624 3 72751773 1937,1732421512 3066630334 31016 31143 257345594 1404119141 2491426864 28809 32pss 34753.
. 11 39 241 491 265D 3570 17433 17785718988-12235 30742 -12 , 198299 655 5737 8504 10917'16092 19387 2075537690:

14 54 332 373'2010 3332562316301 34337.354513-7851 139257.10681103020289 29694123732 32640 35.131 35434 -16 457885 36821154956 5422 5949 1757026673 32.387 '17 13:7570 619 5005 6039 7979 14429 16650 25443 32789 r 28 46 282 287 10258,18313,20258 27185 27494 22423 33266 = 23 445486.1058 1861997611234 20354 23635 33826.35330 ,. 20 134300 93112518 14544 17715,19623 21111 33868 34570 = 23 332 675 1033 183112004 15439 20765 31721 3422518863 .24 527551832 326763118317 lona 13466 12427 25377 431780.10211112 2173 767513059 17793 20570 20771 " 26 ' 3-39536 1013 5725 6916 2084614487 21156 28123 32614 27 456 830, 19787311 1180112362 12705 27402 28367 34032 21 222538 919 55958022 530214098 23445 25127 29022.
29 .31 393 7/130217758 11367 22276 227612823230394 _ 30 .234257 1345 1307 2908 6337:26530 28142 34129'35997:
.31 3146 978 9912997812567 17843 24194 34827 35206 = 32 39959 967 302710147 14657 18859 28075 2821436325:.
33. 275477 823 .113-76-18073'-28997'3052111661 3194132116 .34 185.580 966 1173a 12013 12750 13358 19372.32534.35504 760891 1046 11150 20358 21531.29930 3101433050,34840 37 305344 579 5224667410305 18753 2558330535:35341 55 103 171 101587141174112144 19470. 20955 2/495 27377 . 59 118 832 894 3883 14273 14497 22505 28129.28715 31246, . 215411.7505886 25612 28556 3222312704 35901 36130' . 41 229489 10671385E587 20565 23431 2810230147 32859' 42 28/664. 980 815.8 8531 2167623787 26708 2,8798 34490:' -43 89552 847 6656:9889 23949 26225170101123.6 35823 44 66142 445 3339.5513 7077 14944-1546419186 259,ga 605875 93116512 17659158017 18220.3343235738 37382-' 45 346423 aos 566376688783 3928 19724 2403527835 I 47 '45460 10553512 73:89 7549.29215 2.2180 2522135437 . 48 187531124157a 450113581 19683 21750.3033.1. 31480..
.=49' .257689352856 8187 905211850 299413321734253 = 50 349624 71.6165/ 6333 64358974106491593217378 =

51 ' 336 410 871. 3582 9830 10835 13892 1302T192(33 36659 52 176849 107g 17302 19379 27964 28164 26720 32557 35495 54 516 638 733 6851 19871'22740 25791 30152 32659 35568' 56 94 954 99&2003'3359 6870 7321 29856 31373 34868 - --56- '246547 7784035 10391 10656 13194 32335 32360 34179 _60. 36 149 220 6936 18408 19192 19288 23055 28411 35312 62 46 138 722 2701 10964 13002 19430 2662528458 2E965, 63 12101)9 1040 1990 2930 5302 21215 22625023011 29288 65' 45 476 1075 7393 1514120414 31244 33336 35004 3E391 59' 7Z49492030 4350,&23 9737 19705 13902 3E039 --In the above-described example, the length of the LDPC codeword is 64800 and the code rate 6/15. However, this is merely an example and the indexes of rows where 1 is located in the 06 column of the ith column group in the matrix A and the matrix C may be defined variously when the length of the LDPC codeword is 16200 or the code rate has different values.
Hereinafter, positions of rows where 1 exists in the matrix A and the matrix C
will be explained with reference to table 10 by way of an example.
Since the length N of the LDPC codeword is 64800 and the code rate is 6/15 in table 10, M1=1080, M2=37800, Qi=3, and Q2=105 in the parity check matrix 400 defined by table 10 with reference to table 9.
Herein, Qi is a size by which columns of the same column group are cyclic-shifted in the matrix A, and Q2 is a size by which columns of the same column group are cyclic-shifted in the matrix C.
In addition, Qi=Mi/L, 02=M2/1,, Mi=g, and M2=N-K-g, and L is an interval at which a pattern of a column is repeated in the matrix A and the matrix C, and for example, may be 360.
The index of the row where 1 is located in the matrix A and the matrix C may be determined based on the M1 value.
For example, since M1=1080 in the case of table 10, the positions of the rows where 1 exists in the Oth column of the ith column group in the matrix A may be determined based on values smaller than 1080 from among the index values of table 10, and the positions of the rows where 1 exists in the Oth column of the ith column group in the matrix C may be determined based on values greater than or equal to 1080 from among the index values of table 10.
Specifically, in table 10, the sequence corresponding to the Oth column group is "71, 276, 856, 6867, 12964, 17373, 18159, 26420, 28460, 28477". Accordingly, in the case of the Oth column of the 0th column group of the matrix A, 1 may be located in the 71st row, 276th row, and 856th row, and, in the case of the 0th column of the Oth column group of the matrix C, 1 may be located in the 6867th row, 12964th row, 173731d row, 18159th row, 26420th row, 28460th row, and 28477th row.
Once positions of 1 in the Oth column of each column group of the matrix A are defined, positions of rows where 1 exists in another column of each column group may be defined by cyclic-shifting from the previous column by Qi. Once positions of 1 in the 0th column of each column group of the matrix C are defined, position of rows where 1 exists in another column of each column group may be defined by cyclic-shifting from the previous column by Q2.
In the above-described example, in the case of the 0th column of the Oth column group of the matrix A, 1 exists in the 71st row, 276th row, and 856th row. In this case, since Q1=3, the indexes of rows where 1 exists in the 18t column of the Oth column group are 74(=71+3), 279(.276+3), and 859(=856+3), and the index of rows where 1 exists in the 2nd column of the 0th column group are 77(=74+3), 282 (=279+3), and 862(=859+3).
In the case of the 0th column of the 0th column group of the matrix C, 1 exists in the 6867th row, 12964th row, 17373`d row, 18159th row, 26420th row, 28460th row, and 28477th row. In this case, since Q2=105, the index of rows where 1 exists in the 1st column of the Oth column group are 6972(=6867+105), 13069(=12964+105), 17478(=17373+105), 18264(=18159+105), 26525(=26420+105), 28565(=28460+105), 28582(=28477+105), and the indexes of rows where 1 exists in the 2nd column of the 0th column group are 7077(=6972+105), 13174(.13069+105), 17583(.17478+105), 18369(=18264+105), 26630(.26525+105), 28670(.28565+105), 28687(=28582+105).
In this method, the positions of rows where 1 exists in all column groups of the matrix A and the matrix C are defined.
The matrix B may have a dual diagonal configuration, the matrix D may have a diagonal configuration (that is, the matrix D is an identity matrix), and the matrix Z
may be a zero matrix.
As a result, the parity check matrix 400 shown in FIG. 4 may be defined by the matrices A, B, C, D, and Z having the above-described configurations.
Hereinafter, a method for performing LDPC encoding based on the parity check matrix 400 shown in FIG. 4 will be explained. An LDPC encoding process when the parity check matrix 400 is defined as shown in Table 10 by way of an example will be explained for the convenience of explanation.
For example, when an information word block S=(so, sl, SK_i) is LDPC-encoded, an LDPC codeword A = ( 0===,Aw_i) = (sõ.91,...,Sõ_1,po,p1,...,Pmi,,,,,2_1) including a parity bit P = (Po,191,¨,Pm1+m 2-1) may be generated.
Mi and M2 indicate the size of the matrix B having the dual diagonal configuration and the size of the matrix C having the diagonal configuration, respectively, and Mi=g, M2=N-K-g.
A process of calculating a parity bit is as follows. In the following explanation, the parity check matrix 400 is defined as shown in table 10 by way of an example, for the convenience of explanation.
Step 1) X and p are initialized as Xj=s; (i=0,1,..., K-1), p3=0 (j=0,1,..., Mi+M2-1).
Step 2) The 0th information word bit X0 is accumulated in the address of the parity bit defined in the first row (that is, the row of i=0) of table 10. This may be expressed by Equation 12 presented below:
P71 = P710 k 0 P17373= P17373 0 X 0 P276= P276 ex.0 P18159= P18159 OK 0 P856= P856 0 X 0 P25420 = P26420 .0 P6867 = P68670 X 0 P28460 = P28460 0 X 0 P12964= P 12964 OX0 P28477 = P28477 0 X 0 ...(12) Step 3) Regarding the next L-1 number of information word bits Ain (m=1, 2, ..., L-1), Xin is accumulated in the parity bit address calculated based on Equation 13 presented below:
(x + m x ) mod Mi (if x <
M +{(,' ¨ M 1+ mx Q2) modM2} (if fr )...(13) Herein, x is an address of a parity bit accumulator corresponding to the 0th information word bit ko.

In addition, Q1=M1/L and Q2=M2/L. In addition, since the length N of the LDPC
codeword is 64800 and the code rate is 6/15 in table 10, M1=1080, M2=37800, Q1=3, Q2=105, and L=360 with reference to table 9.
Accordingly, an operation as shown in Equation 14 presented below may be performed for the 1St information word bit Xi:
P74= P74 X1 P17478 = P17478 OA- 1 P279= P2790 A-1 P18264 P18264 0 k 1 P859= P85910 A- 1 P26525= P26525 0 A- 1 P6972 = P69720 A- 1 P28565= P28565 A- 1 P13069 = P130690 A- 1 P28582= P285820 A-1 ...(14) Step 4) Since the same address of the parity bit as in the second row (that is the row of i=1) of table 10 is given to the Lth information word bit XL, in a similar method to the above-described method, the address of the parity bit regarding the next L-1 number of information word bits A.,õ
(m=L+1, L+2, 2L-1) is calculated based on Equation 13. In this case, x is the address of the parity bit accumulator corresponding to the information word bit XL, and may be obtained based on the second row of table 10.
Step 5) The above-described processes are repeated for L number of new information word bits of each group by considering new rows of table 10 as the address of the parity bit accumulator.
Step 6) After the above-described processes are repeated for the codeword bits Ao to kx-i, values regarding Equation 15 presented below are calculated in sequence from i=1:
Step 7) Parity bits kic to corresponding to the matrix B having the dual diagonal configuration are calculated based on Equation 16 presented below:
2K4-Lxt+s = PQixS+t (0 s <L,0 t <Q1) ...(16) Step 8) The address of the parity bit accumulator regarding L number of new codeword bits XIC to Alc+mi_i of each group is calculated based on table 10 and Equation 13.
Step 9) After the codeword bits kic to are calculated, parity bits 2,c+mi to .1./c,mi+m,_1 corresponding to the matrix C having the diagonal configuration are calculated based on Equation 17 presented below:
K+Mi q,xt+s = P (0 S <L,0 t <Q2) ...(17) As a result, the parity bits may be calculated in the above-described method.
Referring back to FIG. 1, the encoder 110 may perform the LDPC encoding by using various code rates such as 3/15, 4/15, 5/15, 6/15, 7/15, 8/15, 9/15, 10/15, 11/15, 12/15, 13/15, etc. In addition, the encoder 110 may generate an LDPC codeword having various lengths such as 16200, 64800, etc., based on the length of the information word bits and the code rate.
In this case, the encoder 110 may perform the LDPC encoding by using the parity check matrix, and the parity check matrix is configured as shown in FIGS. 2 to 4.
In addition, the encoder 110 may perform Bose, Chaudhuri, Hocquenghem (BCH) encoding as well as LDPC encoding. To achieve this, the encoder 110 may further include a BCH encoder (not shown) to perform BCH encoding.
In this case, the encoder 110 may perform encoding in an order of BCH encoding and LDPC
encoding. Specifically, the encoder 110 may add BCH parity bits to input bits by performing BCH encoding and LDPC-encodes the information word bits including the input bits and the BCH parity bits, thereby generating the LDPC codeword.
The interleaver 120 interleaves the LDPC codeword. That is, the interleaver 120 receives the LDPC codeword from the encoder 110, and interleaves the LDPC codeword based on various interleaving rules.
In particular, the interleaver 120 may interleave the LDPC codeword such that a bit included in a predetermined bit group from among a plurality of bit groups constituting the LDPC
codeword (that is, a plurality of groups or a plurality of blocks) is mapped onto a predetermined bit of a modulation symbol. Accordingly, the modulator 130 may map a bit included in a predetermined group from among the plurality of groups of the LDPC codeword onto a predetermined bit of the modulation symbol.
To achieve this, as shown in FIG. 5, the interleaver 120 may include a parity interleaver 121, a group interleaver (or a group-wise interleaver 122), a group twist interleaver 123 and a block interleaver 124.
The parity interleaver 121 interleaves the parity bits constituting the LDPC
codeword.
Specifically, when the LDPC codeword is generated based on the parity check matrix 200 having the configuration of FIG. 2, the parity interleaver 121 may interleave only the parity bits of the LDPC codeword by using Equations 18 presented below:
14, = C, for 0<i<Kkipc, and = cicia +0,õ .s.õ for 0.s<M, 05A<Qmpc = = = (18), where M is an interval at which a pattern of a column group is repeated in the information word submatrix 210, that is, the number of columns included in a column group (for example, M=360), and Qldp, is a size by which each column is cyclic-shifted in the information word submatrix 210. That is, the parity interleaver 121 performs parity interleaving with respect to the LDPC codeword c=(co, C),/,,,_1), and outputs U=(uo, tiNwpc_i).
The LDPC codeword parity-interleaved in the above-described method may be configured such that a predetermined number of continuous bits of the LDPC codeword have similar decoding characteristics (cycle distribution, a degree of a column, etc.).
For example, the LDPC codeword may have the same characteristics on the basis of M
number of continuous bits. Herein, M is an interval at which a pattern of a column group is repeated in the information word submatrix 210 and, for example, may be 360.
Specifically, a product of the LDPC codeword bits and the parity check matrix should be "0".
This means that a sum of products of the ith LDPC codeword bit, ci(i=0, 1, ..., N1dix-1) and the ith column of the parity check matrix should be a "0" vector. Accordingly, the ith LDPC codeword bit may be regarded as corresponding to the ith column of the parity check matrix.
In the case of the parity check matrix 200 of FIG. 2, M number of columns in the information word submatrix 210 belong to the same group and the information word submatrix 210 has the same characteristics on the basis of a column group (for example, the columns belonging to the same column group have the same degree distribution and the same cycle characteristic).
In this case, since M number of continuous bits in the information word bits correspond to the same column group of the information word submatrix 210, the information word bits may be formed of M number of continuous bits having the same codeword characteristics. When the parity bits of the LDPC codeword are interleaved by the parity interleaver 121, the parity bits of the LDPC codeword may be formed of M number of continuous bits having the same codeword characteristics.
However, regarding the LDPC codeword encoded based on the parity check matrix 300 of FIG. 3 and the parity check matrix 400 of FIG. 4, parity interleaving may not be performed. In this case, the parity interleaver 121 may be omitted.
The group interleaver 122 may divide the parity-interleaved LDPC codeword into a plurality of bit groups and rearrange the order of the plurality of bit groups in bit group wise (or bit group unit). That is, the group interleaver 122 may interleave the plurality of bit groups in bit group wise.
To achieve this, the group interleaver 122 divides the parity-interleaved LDPC
codeword into a plurality of bit groups by using Equation 19 or Equation 20 presented below.
X.I ={uk 1 j=[¨k ],0 k < Ndpc } for j < Ngroup 360 l ... (19) Xi = 1E441360 x j k < 360 x ( j +1),0 k < N hipci for j < N grõup . . . (20) where Ng,õõp is the total number of bit groups, N is the jth bit group, and uk is the kth LDPC codeword bit input to the group interleaver 122. In addition, ¨k is the largest integer below k/360.
[

Since 360 in these equations indicates an example of the interval M at which the pattern of a column group is repeated in the information word submatrix, 360 in these equations can be changed to M.
The LDPC codeword which is divided into the plurality of bit groups may be as shown in FIG.
6.
Referring to FIG. 6, the LDPC codeword is divided into the plurality of bit groups and each bit group is formed of M number of continuous bits. When M is 360, each of the plurality of bit groups may be formed of 360 bits. Accordingly, the bit groups may be formed of bits corresponding to the column groups of the parity check matrix.
Specifically, since the LDPC codeword is divided by M number of continuous bits, Kidpc number of information word bits are divided into (Kkipc/M) number of bit groups and Nmpc-Kidpc number of parity bits are divided into (I\lidpc-Kwpc)/M number of bit groups.
Accordingly, the LDPC codeword may be divided into (Islidpc/M) number of bit groups in total.
For example, when M=360 and the length Nidpc of the LDPC codeword is 16200, the number of groups Ngroups constituting the LDPC codeword is 45(.16200/360), and, when M=360 and the length Nidpc of the LDPC codeword is 64800, the number of bit groups Ngroup constituting the LDPC codeword is 180(=64800/360).
As described above, the group interleaver 122 divides the LDPC codeword such that M
number of continuous bits are included in a same group since the LDPC codeword has the same codeword characteristics on the basis of M number of continuous bits.
Accordingly, when the LDPC codeword is grouped by M number of continuous bits, the bits having the same codeword characteristics belong to the same group.
In the above-described example, the number of bits constituting each bit group is M. However, this is merely an example and the number of bits constituting each bit group is variable.
For example, the number of bits constituting each bit group may be an aliquot part of M. That is, the number of bits constituting each bit group may be an aliquot part of the number of columns constituting a column group of the information word submatrix of the parity check matrix. In this case, each bit group may be formed of aliquot part of M number of bits. For example, when the number of columns constituting a column group of the information word submatrix is 360, that is, M=360, the group interleaver 122 may divide the LDPC codeword into a plurality of bit groups such that the number of bits constituting each bit group is one of the aliquot parts of 360.
In the following explanation, the number of bits constituting a bit group is M
by way of an example, for the convenience of explanation.
Thereafter, the group interleaver 122 interleaves the LDPC codeword in bit group wise.
Specifically, the group interleaver 122 may group the LDPC codeword into the plurality of bit groups and rearrange the plurality of bit groups in bit group wise. That is, the group interleaver 122 changes positions of the plurality of bit groups constituting the LDPC
codeword and rearranges the order of the plurality of bit groups constituting the LDPC
codeword in bit group wise.
Herein, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise such that bit groups including bits mapped onto the same modulation symbol from among the plurality of bit groups are spaced apart from one another at predetermined intervals.
In this case, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by considering at least one of the number of rows and columns of the block interleaver 124, the number of bit groups of the LDPC codeword, and the number of bits included in each bit group, such that bit groups including bits mapped onto the same modulation symbol are spaced apart from one another at predetermined intervals.
To achieve this, the group interleaver 122 may rearrange the order of the plurality of groups in bit group wise by using Equation 21 presented below:
Y., = X,(j)(0 j<N ) gr uP (21), where x.; is the ith bit group before group interleaving, and Yj is the ith bit group after group interleaving. In addition, 7r(j) is a parameter indicating an interleaving order and is determined by at least one of a length of an LDPC codeword, a modulation method, and a code rate. That is, n(j) denotes a permutation order for group wise interleaving.
Accordingly, X,,o) is a n(j)th bit group before group interleaving, and Equation 21 means that the pre-interleaving n(j)th bit group is interleaved into the jth bit group.
According to an exemplary embodiment, an example of n(j) may be defined as in Tables 11 to 22 presented below.
In this case, n(j) is defined according to a length of an LPDC codeword and a code rate, and a parity check matrix is also defined according to a length of an LDPC codeword and a code rate.
Accordingly, when LDPC encoding is performed based on a specific parity check matrix according to a length of an LDPC codeword and a code rate, the LDPC codeword may be interleaved in bit group wise based on n(j) satisfying the corresponding length of the LDPC
codeword and code rate.
For example, when the encoder 110 performs LDPC encoding at a code rate of 6/15 to generate an LDPC codeword of a length of 64800, the group interleaver 122 may perform interleaving by using n(j) which is defined according to the length of the LDPC codeword of 16200 and the code rate of 6/15 in tables 11 to 22 presented below.
For example, when the length of the LDPC codeword is 64800, the code rate is 6/15, and the modulation method(or modulation format) is 16-Quadrature Amplitude Modulation (QAM), t(j) may be defined as in table 11 presented below. In particular, table 11 may be applied when LDPC encoding is performed based on the parity check matrix defined by table 4.
[Table 11]
Order of bit groups to be block interleaved rc(j) (0 j <180) j-th Li of 0 I 1 2 3 4 5 6 7 8 9 group_ 23 2 2 2 2 2 2 3 3 3 3 3 3 3 wise interleaver 7 8 9 0 1 2 3 4 5 6 7 8 9 output 69 7L6)-th 3 14 5 4 6 4 1 4 2 3 2 3 2 3 block of group- 8 8 3 2 9 1 0 6 1 0 3 0 5 4 0 7 2 6 wise 12 1 9 1 1 3 1 1 7 1 1 1 1 1 interleaver input 71 42 78 54 5 07 5 2 51 7 17 In the case of Table 11, Equation 21 may be expressed as YO=X70)=X55, Yi=Xx(1)=X146, Y2=X(2)=X-83, = = =, Y178=X7(l78)=X132, and Yi79=X7(l79)=X135. Accordingly, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by changing the 551h bit group to the 0th bit group, the 146th bit group to the 1st bit group, the 83rd bit group to the 2nd bit group, ..., the 132nd bit group to the 1781h bit group, and the 135th bit group to the 179th bit group.
In another example, when the length of the LDPC codeword is 64800, the code rate is 8/15, and the modulation method is 16-QAM, n(j) may be defined as in table 12 presented below. In particular, table 12 may be applied when LDPC encoding is performed based on the parity check matrix defined by table 5.
[Table 12]
j-th Order of bit groups to be block interleaved block of n(j) (0 <j < 180) group- 1 2 3 4 5 6 7 8 9 1 1 1 1 wise interleaver 4 5 6 7 8 9 0 1 2 3 4 5 6 output 46 ic(j)-th 92 1 6 6 2 2 2 2 6 5 7 5 4 block of ________________________________________________________________________ group- 4 1 7 0 2 0 0 1 8 9 7 4 5 Wise 1 1 3 1 1 1 1 1 1 1 1 1 interleaver _____________________________________________________________________ input 0 42 6 4 61 70 34 56 2 54 74 45 46 4 24 6 02 33 76 32 35 In the case of Table 12, Equation 21 may be expressed as Y0=X70)=X58, Yi=Xn0)=X55, Y2=X7,(2)=Xiii, = = =, Y178=Xx(178)=X171, and Yr9=Xic(179)=X155. Accordingly, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by changing the 58th bit group to the 0th bit group, the 55th bit group to the 1st bit group, the 111111 bit group to the 2nd bit group, ..., the 171st bit group to the 178th bit group, and the 1551h bit group to the 179th bit group.
In another example, when the length of the LDPC codeword is 64800, the code rate is 10/15, and the modulation method is 16-QAM, n(j) may be defined as in table 13 presented below. In particular, table 13 may be applied when LDPC encoding is performed based on the parity check matrix defined by table 6.
[Table 13]
j-th Order of bit groups to be block interleaved block of it(j) (0 <j < 180) group- 1 2 3 4 5 6 7 8 9 wise 23 2 2 2 2 2 2 3 3 3 3 3 3 3 interleaver _____________________________________________________________________ output 7 8 9 0 1 2 3 4 5 6 7 8 9 0 7[0)-th 10 8 3 7 3 8 7 6 5 7 1 4 1 8 block of group- 05 19 9 2 0 01 14 2 7 5 17 3 5 7 6 8 12 8 06 wise 16 7 1 5 2 6 1 7 1 6 2 2 1 9 interleaver _____________________________________________________________________ input 7 1 61 62 23 38 73 77 00 2 7 37 32 69 58 3 1 7 68 43 31 In the case of Table 13, Equation 21 may be expressed as Y0=X70)=X74, Yi=Xki)=X53, Y2=Xx(2)=X84, Yi78=X/(l78)=X159, and Yi79=Xn(i79)=X163. Accordingly, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by changing the 74th bit group to the 0th bit group, the 53rd bit group to the 18t bit group, the 841h bit group to the 2" bit group, ..., the 159th bit group to the 178th bit group, and the 163rd bit group to the 179th bit group.
In another example, when the length of the LDPC codeword is 64800, the code rate is 10/15, and the modulation method is 16-QAM, it(j) may be defined as in table 14 presented below. In particular, table 14 may be applied when LDPC encoding is performed based on the parity check matrix defined by table 7.
[Table 14]
j-th Order of bit groups to be block interleaved block of rc(j) (0 j <180) group- 1 2 3 4 5 6 7 8 9 wise interleaver 4 5 6 7 8 9 0 1 2 3 4 5 6 output 46 Tta)-111 38 7 1 5 8 1 1 7 7 6 4 9 3 block of group- 4 4 4 11 5 0 4 5 0 0 7 01 wise 3 50 1 5 1 1 1 8 1 1 1 1 1 1 interleaver input 58

20 2 2 9 46 44 8 55 28 65 41 79 50 57 71 43 08 70 2 9 In the case of Table 14, Equation 21 may be expressed as Yo=¨Xls(0)=X683 Y1=Xx(1)=X713 Y2=Xit(2)=X54, = = = Yi78=Xn(178)=X135, and Yr9=X,(l79)=X2.4. Accordingly, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by changing the 68th - =
bit group to the 01h bit group, the 71st bit group to the 1st bit group, the 54th bit group to the 2nd bit group, ..., the 135th bit group to the 1781h bit group, and the 24th bit group to the 179th bit group.
In another example, when the length of the LDPC codeword is 64800, the code rate is 12/15, and the modulation method is 16-QAM, Ir(j) may be defined as in table 15 presented below. In particular, table 15 may be applied when LDPC encoding is performed based on the parity check matrix defined by table 8.
[Table 15]

Order of bit groups to be block interleaved rc(j) (0 j <180) j-th 23 block of 4 4 4 5 5 5 5 5 5 5 5 5 5 group-wise 69 interleaver 9 9 9 9 9 9 9 1 1 1 1 1 1 output 11 1 1 1 1 1 1 1 1 1 1 1 1' 1 1 1 it(j)-th 9 9 4 7 2 1 8 1 2 9 7 1 1 block of group- 04 24 2 0 18 4 wise 17 1 1 1 1 1 1 1 1 1 1 1 1 1 interleaver input 3 52 46 77 03 60 47 6 72 44 50 32 76 68 67 62 70 38 51 61 0 6 30 In the case of Table 15, Equation 21 may be expressed as YO=X*0)=Xi2o, Yt=Xx(I)=X32, Y2=3Q2)=X38, = = =, Y178;---X7(l78)=Xtot, and Yr9=-X2r(179)=X39. Accordingly, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by changing the 120th bit group to the 0111 bit group, the 32'd bit group to the 15t bit group, the 38th bit group to the 2nd bit group, ..., the 101st bit group to the 178th bit group, and the 391h bit group to the 179th bit group.
In another example, when the length of the LDPC codeword is 64800, the code rate is 6/15, and the modulation method is 16-QAM, n(j) may be defined as in table 16 presented below. In particular, table 16 may be applied when LDPC encoding is performed based on the parity check matrix defined by table 10.
[Table 16]
Order of bit groups to be block interleaved it(j) (0 5 j <180) j-th 23 block of 4 4 4 5 5 5 5 5 5 5 5 5 5 group- 7 8 9 0 1 2 3 4 5 6 7 8 9 0 wise 69 interleaver 9 9 9 9 9 9 9 1 1 1 1 1 1 output _ rc(j)-th 6 1 6 8 1 4 1 1 6 6 8 3 1 block of group- 33 7 9 6 8 55 1 6 6 9 8 2 54 3 1 4 wise 14 3 2 2 1 3 611 3 5 911 2 7 interleaver = 46 4 7 input 66 7 61 74 9 3 1 39 8 2 9 49 15 01 27 2 58 In the case of Table 16, Equation 21 may be expressed as Y0=X70)=X163, Yi=X/K0=Xi6o, Y2=Xik2)=X138, = = = , Yi78=X7(l78)=X148, and Yi79=X,1(l79)=X98. Accordingly, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by changing the 163"I
bit group to the 0th bit group, the 160th bit group to the 1st bit group, the 138th bit group to the 2nd bit group, ..., the 148th bit group to the 1781h bit group, and the 98th bit group to the 179th bit group.
In another example, when the length of the LDPC codeword is 64800, the code rate is 6/15, and the modulation method is 64-QAM, it(j) may be defined as in table 17 presented below. In particular, table 17 may be applied when LDPC encoding is performed based on the parity check matrix defined by table 4.
[Table 17]
Order of bit groups to be block interleaved rc(j) (0 j <180) j-th 23 block of 4 4 4 5 5 5 5 5 5 5 5 5 5 group- 7 8 9 0 1 2 3 4 5 6 7 8 9 0 wise 69 0 1 2 3 4 5 6 7 8 9 (1 1 2 3 interleaver 9 9 9 9 9 9 9 1 1 1 1 1 1 output rc(j)-th 16 1 5 6 5 6 5 1 7 5 1 6 3 block of group- 3 8 8 229 37 0 3 66 5 7 42 74 5 49 8 45 2 69 0 33 63 19 wise 82 0 1 1 1 1 1 1 9 1 1 8 1 1 interleaver input 0 18 27 4 9 08 26 31 3 11 1 425 62 57 58 09 40 23 54 50 0 1 In the case of Table 17, Equation 21 may be expressed as Yo.--X,0)=X2.9, Yi=X*1)=X17, Y2=Xx(2)=X3s, = = =, Yi78=X7(l78)=Xir, and Yi79=X7(J79)=X155. Accordingly, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by changing the 29th bit group to the 0th bit group, the 17th bit group to the 1st bit group, the 38th bit group to the 2nd bit th th group, ..., the 117th bit group to the 178 bit group, and the 155th bit group to the 179 bit group.

In another example, when the length of the LDPC codeword is 64800, the code rate is 8/15, and the modulation method is 64-QAM, 7r(j) may be defined as in table 18 presented below. In particular, table 18 may be applied when LDPC encoding is performed based on the parity check matrix defined by table 5.
[Table 18]
Order of bit groups to be block interleaved TE(j) (0 j <180) j-th 23 block of group-wise 69 interleaver 9 9 9 9 9 9 9 1 1 1 1 1 1 output 16 17 18 19 20 21 22 2.3 24 25 26 27 28 29 30 31 32 33 34 35 36 37 1 2 0 0 0 8 3 8 7 5 (1 9 3 4 7C(J)-th 9 6 5 8 7 1 8 7 6 8 7 1 1 block of group-

21 08 39 42 4 4 0 57 59 38 43 9 40 63 50 75 14 1 2 5 45 8 wise 2 1 9 1 1 1 1 2 2 1 1 4 1 2 1 .. 1 .. 5 .. 1 .. 1 .. 1 interleaver input 34 1 4 79 29 69 01 9 09 27 68 76 In the case of Table 18, Equation 21 may be expressed as Y0=- -3(70)=X86, Y1=X7,(1)=X71, Y2=X*2)=X51, = = = 5 Y178=Xx(178)=X174, and Yi79=Xx(179)=X128- Accordingly, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by changing the 861h bit group to the Oth bit group, the 7181 bit group to the 1st bit group, the 51st bit group to the 2nd bit group, ..., the 174th bit group to the 178th bit group, and the 128th bit group to the 179th bit group.
In another example, when the length of the LDPC codeword is 64800, the code rate is 10/15, and the modulation method is 64-QAM, ir(j) may be defined as in table 19 presented below. In particular, table 19 may be applied when LDPC encoding is performed based on the parity check matrix defined by table 6.
[Table 19]
Order of bit groups to be block interleaved n(j) (0 5 j < 180) j-th 23 block of -group- 7 8 9 0 1 2 3 4 5 6 7 8 9 0 wise 69 interleaver 9 9 9 9 9 9 9 1 1 1 1 1 1 output -7t(1)-th 8 5 6 7 1 8 1 6 1 1 6 4 - 1 block of _________________________________________________________________________ 54 group- 7 7 8 1 5 3 17 7 10 2 4 2 18 7 8 8 6 0 1 4 wise 15 2 1 4 5 interleaver input 54 1 69 1 71 62 39 75 29 5 67 In the case of Table 19, Equation 21 may be expressed as Yo.X7,0)=X73, Yi.Xõ(1)=X36, Y2=X2(2)=X2i, = = =, Y178=Xx(178)=X149, and Yi79=X7(l79)=X135. Accordingly, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by changing the 73rd bit group to the Of" bit group, the 361h bit group to the 181 bit group, the 21st bit group to the 2nd bit group, ..., the 149th bit group to the 1781h bit group, and the 135th bit group to the 179th bit group.
In another example, when the length of the LDPC codeword is 64800, the code rate is 10/15, and the modulation method is 64-QAM, ir(j) may be defined as in table 20 presented below. In particular, table 20 may be applied when LDPC encoding is performed 'based on the parity check matrix defined by table 7.
[Table 20]
Order of bit groups to be block interleaved n(j) (0 j <180) j-th 23 block of 4 4 4 5 5 5 5 5 5 5 5 5 5 group-wise 69 interleaver 9 9 9 9 9 9 9 1 1 1 1 1 1 output 7t(j)-th 1 6 1 3 1 5 1 3 9 7 9 1 8 block of group- 4829 7 7 4 9 3 00 4 1 73 69 3 49 04 0 1 02 10 24 0 9 8 wise 19 0 5 interleaver input 6 5 1 0 1 68 21 53 40 52 35 =.!Atto.-In the case of Table 20, Equation 21 may be expressed as 110=X70)=X113, Yi=Xx(1)=X115, Y2=Xn(2)=X47, = = Y178=Xx(178)=X130, and Y179=Xir(I79)=X176. Accordingly, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by changing the 113th bit group to the 0th bit group, the 115th bit group to the 1st bit group, the 47th bit group to the 2nd bit group, ..., the 130th bit group to the 178th bit group, and the 176th bit group to the 179th bit group.
In another example, when the length of the LDPC codeword is 64800, the code rate is 12/15, and the modulation method is 64-QAM, Ir(j) may be defined as in table 21 presented below. In particular, table 21 may be applied when LDPC encoding is performed based on the parity check matrix defined by table 8.
[Table 21]
Order of bit groups to be block interleaved n(j) (0 j <180) j-th 23 block of 4 4 4 5 5 5 5 5 5 5 5 5 5 group- 7 8 9 0 1 2 3 4 5 6 7 8 9 0 wise 69 interleaver 9 9 9 9 9 9 9 1 1 1 1 1 1 output n(j)-th 10 7 2 6 7 2 1 8 9 1 1 1 2 4 block of group-wise 29 interleaver input 6 23 14 0 07 78 45 73 6 44 30 76 71 75 25 9 62 59 0 64 15 69 72 In the case of Table 21, Equation 21 may be expressed as Y0=X70)=X83, Y1=Xrr(1)=X939 Y2=Xn(2)=X94, = = =, Y178=XE(178)--=X2, and Yi79=X179)=X14. Accordingly, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by changing the 83r1 pit r group to the 0th bit group, the 93' bit group to the lst bit group, the 94"
bit group to the 2' bit =
group, the 2" bit group to the 178di bit group, and the 14th bit group to the 179th bit group.
In another example, when the length of the LDPC codeword is 64800, the code rate is 6/15, and the modulation method is 64-QAM, Ic(j) may be defined as in table 22 presented below. In particular, table 22 may be applied when LDPC encoding is performed based on the parity check matrix defined by table 10.
[Table 22]
Order of bit groups to be block interleaved Tt(j) (0 j <180) j -th 23 block of - 4 4 4 5 5 5 5 5 5 5 5 5 group- 7 8 9 0 1 2 3 4 5 6 7 8 9 0 wise 69 interleaver 9 9 9 9 9 9 9 1 1 1 1 1 1 output _ 74.1)-th block of 64 55 1 02 3 1 1 7 1 26 7 6 group- 8 5 3 wise 7 1 7 1 4 3 3 2 1 4 6 4 1 interleaver 1 07 7 11 2 5 8 3 GO 5 9 0 29 3 63 9 12 45 4 05 17 inut lo 12 I 60 1 35 32 34 I 4 I 46 I 4 I 20 1 58 138 In the case of Table 22, Equation 21 may be expressed as Y0=X70)=X175, Y1=Xx(j)=X177, Y2=XX(2)=X1731 = = = Y178=XTE(178)=X31, and Y179=Xn(179)=X72- Accordingly, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by changing the 175th bit group to the 0th bit group, the 177th bit group to the 1st bit group, the 173rd bit group to the fd bit group, ..., the 31st bit group to the 178111 bit group, and the 72nd bit group to the 179111 bit group.
In the above-described examples, the length of the LDPC codeword is 64800 and the code rate is 6/15, 8/15, 10/15, and 12/15. However, this is merely an example and the interleaving pattern may be defined variously when the length of the LDPC codeword is 16200 or the code rate has different values.
As described above, the group interleaver 122 may rearrange the order of the plurality of bit groups in bit group wise by using Equation 21 and Tables 11 to 22.
"j-th block of Group-wise Interleaver output" in tables 11 to 22 indicates the j-th bit group output from the group interleaver 122 after interleaving, and "n(j)-th block of Group-wise Interleaver input" indicates the 7r(j)-th bit group input to the group interleaver 122.
In addition, since the order of the bit groups constituting the LDPC codeword is rearranged by the group interleaver 122 in bit group wise, and then the bit groups are block-interleaved by the block interleaver 124, which will be described below, "Order of bit groups to be block interleaved" is set forth in Tables 11 to 22 in relation to n(j).
The LDPC codeword which is group-interleaved in the above-described method is illustrated in FIG. 7. Comparing the LDPC codeword of FIG. 7 and the LDPC codeword of FIG.
6 before group interleaving, it can be seen that the order of the plurality of bit groups constituting the LDPC codeword is rearranged.
That is, as shown in FIGs. 6 and 7, the groups of the LDPC codeword are arranged in order of bit group )Co, bit group Xi, ..., bit group XNgr00p-1 before being group-interleaved, and are arranged in an order of bit group Yo, bit group Yi, ..., bit group Y
- Ngroup-1 after being group-interleaved. In this case, the order of arranging the bit groups by the group interleaving may be determined based on Tables 11 to 22.
The group twist interleaver 123 interleaves bits in a same group. That is, the group twist interleaver 123 may rearrange the order of the bits in the same bit group by changing the order of the bits in the same bit group.
In this case, the group twist interleaver 123 may rearrange the order of the bits in the same bit group by cyclic-shifting a predetermined number of bits from among the bits in the same bit group.
For example, as shown in FIG. 8, the group twist interleaver 123 may cyclic-shift bits included in the bit group Y1 to the right by 1 bit. In this case, the bits located in the 0th position, the 1st position, the 2hd position, ..., the 358th position, and the 359th position in the bit group Y1 as shown in FIG. 8 are cyclic-shifted to the right by 1 bit. As a result, the bit located in the 359th position before being cyclic-shifted is located in the front of the bit group Yi and the bits located in the 0th position, the 1st position, the 2nd position, ..., the 358th position before being cyclic-shifted are shifted to the right serially by 1 bit and located.
In addition, the group twist interleaver 123 may rearrange the order of bits in each bit group by cyclic-shifting a different number of bits in each bit group.
For example, the group twist interleaver 123 may cyclic-shift the bits included in the bit group Y1 to the right by 1 bit, and may cyclic-shift the bits included in the bit group Y2 to the right by 3 bits.
However, the above-described group twist interleaver 123 may be omitted according to circumstances.
In addition, the group twist interleaver 123 is placed after the group interleaver 122 in the above-described example. However, this is merely an example. That is, the group twist interleaver 123 changes only the order of bits in a certain bit group and does not change the order of the bit groups. Therefore, the group twist interleaver 123 may be placed before the group interleaver 122.
The block interleaver 124 interleaves the plurality of bit groups the order of which has been rearranged. Specifically, the block interleaver 124 may interleave the plurality of bit groups the order of which has been rearranged by the group interleaver 122 in bit group wise (or bits group unit). The block interleaver 124 is formed of a plurality of columns each including a plurality of rows and may interleave by dividing the plurality of rearranged bit groups based on a modulation order determined according to a modulation method.
In this case, the block interleaver 124 may interleave the plurality of bit groups the order of which has been rearranged by the group interleaver 122 in bit group wise.
Specifically, the block interleaver 124 may interleave by dividing the plurality of rearranged bit groups according to a modulation order by using a first part and a second part.
Specifically, the block interleaver 124 interleaves by dividing each of the plurality of columns into a first part and a second part, writing the plurality of bit groups in the plurality of columns of the first part serially in bit group wise, dividing the bits of the other bit groups into groups (or sub bit groups) each including a predetermined number of bits based on the number of columns, and writing the sub bit groups in the plurality of columns of the second part serially.
Herein, the number of bit groups which are interleaved in bit group wise may be determined by at least one of the number of rows and columns constituting the block interleaver 124, the number of bit groups and the number of bits included in each bit group. In other words, the block interleaver 124 may determine the bit groups which are to be interleaved in bit group wise considering at least one of the number of rows and columns constituting the block interleaver 124, the number of bit groups and the number of bits included in each bit group, interleave the corresponding bit groups in bit group wise, and divide bits of the other bit groups into sub bit groups and interleave the sub bit groups. For example, the block interleaver 124 may interleave at least part of the plurality of bit groups in bit group wise using the first part, and divide bits of the other bit groups into sub bit groups and interleave the sub bit groups using the second part.
Meanwhile, interleaving bit groups in bit group wise means that the bits included in the same bit group are written in the same column. In other words, the block interleaver 124, in case of bit groups which are interleaved in bit group wise, may not divide the bits included in the same bit groups and write the bits in the same column, and in case of bit groups which are not interleaved in bit group wise, may divide the bits in the bit groups and write the bits in different columns.
Accordingly, the number of rows constituting the first part is a multiple of the number of bits included in one bit group (for example, 360), and the number of rows constituting the second part may be less than the number of bits included in one bit group.
In addition, in all bit groups interleaved by the first part, the bits included in the same bit group are written and interleaved in the same column of the first part, and in at least one group interleaved by the second part, the bits are divided and written in at least two columns of the second part.
The specific interleaving method will be described later.
Meanwhile, the group twist interleaver 123 changes only the order of bits in the bit group and does not change the order of bit groups by interleaving. Accordingly, the order of the bit groups to be block-interleaved by the block interleaver 124, that is, the order of the bit groups to be input to the block interleaver 124, may be determined by the group interleaver 122. Specifically, the order of the bit groups to be block-interleaved by the block interleaver 124 may be determined by 7r(j) defined in Tables 11 to 22.
As described above, the block interleaver 124 may interleave the plurality of bit groups the order of which has been rearranged in bit group wise by using the plurality of columns each including the plurality of rows.
In this case, the block interleaver 124 may interleave the LDPC codeword by dividing the plurality of columns into at least two parts. For example, the block interleaver 124 may divide each of the plurality of columns into the first part and the second part and interleave the plurality of bit groups constituting the LDPC codeword.
In this case, the block interleaver 124 may divide each of the plurality of columns into N
number of parts (N is an integer greater than or equal to 2) according to whether the number of bit groups constituting the LDPC codeword is an integer multiple of the number of columns constituting the block interleaver 124, and may perform interleaving.
When the number of bit groups constituting the LDPC codeword is an integer multiple of the number of columns constituting the block interleaver 124, the block interleaver 124 may interleave the plurality of bit groups constituting the LDPC codeword in bit group wise without dividing each of the plurality of columns into parts.
Specifically, the block interleaver 124 may interleave by writing the plurality of bit groups of the LDPC codeword on each of the columns in bit group wise in a column direction, and reading each row of the plurality of columns in which the plurality of bit groups are written in bit group wise in a row direction.
In this case, the block interleaver 124 may interleave by writing bits included in a predetermined number of bit groups, which corresponds to a quotient obtained by dividing the number of bit groups of the LDPC codeword by the number of columns of the block interleaver 124, on each of the plurality of columns serially in a column direction, and reading each row of the plurality of columns in which the bits are written in a row direction.
Hereinafter, the group located in the jth position after being interleaved by the group interleaver 122 will be referred to as group Y.

For example, it is assumed that the block interleaver 124 is formed of C
number of columns each including R1 number of rows. In addition, it is assumed that the LDPC
codeword is formed of Nom, number of bit groups and the number of bit groups Ngroup is a multiple of C.
In this case, when the quotient obtained by dividing Ngroup number of bit groups constituting the LDPC codeword by C number of columns constituting the block interleaver 124 is A
(=NgrOUp/C) (A is an integer greater than 0), the block interleaver 124 may interleave by writing A
(=Ngroup/C) number of bit groups on each column serially in a column direction and reading bits written on each column in a row direction.
For example, as shown in FIG. 9, the block interleaver 124 writes bits included in bit group Yo, bit group bit group YA_-1 in the 1st column from the 1st row to the Rith row, writes bits included in bit group YA, bit group YA+1, , bit group Y2A4 in the 2nd column from the 1st row to the Rig' row, ..., and writes bits included in bit group YCA-A, bit group YCA-A+1, , bit group YcA-1 in the column C from the 1st row to the RP row. The block interleaver 124 may read the bits written in each row of the plurality of columns in a row direction.
Accordingly, the block interleaver 124 interleaves all bit groups constituting the LDPC
codeword in bit group wise.
However, when the number of bit groups of the LDPC codeword is not an integer multiple of the number of columns of the block interleaver 124, the block interleaver 124 may divide each column into 2 parts and interleave a part of the plurality of bit groups of the LDPC codeword in bit group wise, and divide bits of the other bit groups into sub bit groups and interleave the sub bit groups. In this case, the bits included in the other bit groups, that is, the bits included in the number of groups which correspond to the remainder when the number of bit groups constituting the LDPC codeword is divided by the number of columns are not interleaved in bit group wise, but interleaved by being divided according to the number of columns.
Specifically, the block interleaver 124 may interleave the LDPC codeword by dividing each of the plurality of columns into two parts.
In this case, the block interleaver 124 may divide the plurality of columns into the first part and the second part based on at least one of the number of columns of the block interleaver 124, the number of bit groups of the LDPC codeword, and the number of bits of bit groups.
Here, each of the plurality of bit groups may be formed of 360 bits. In addition, the number of bit groups of the LDPC codeword is determined based on the length of the LDPC
codeword and the number of bits included in the bit group. For example, when an LDPC
codeword in the length of 16200 is divided such that each bit group has 360 bits, the LDPC
codeword is divided into 45 bit groups. Alternatively, when an LDPC codeword in the length of 64800 is divided such that each bit group has 360 bits, the LDPC codeword may be divided into 180 bit groups.
Further, the number of columns constituting the block interleaver 124 may be determined according to a modulation method. This will be explained in detail below.
Accordingly, the number of rows constituting each of the first part and the second part may be determined based on the number of columns constituting the block interleaver 124, the number of bit groups constituting the LDPC codeword, and the number of bits constituting each of the plurality of bit groups.
Specifically, in each of the plurality of columns, the first part may be formed of as many rows as the number of bits included in at least one bit group which can be written in each column in bit group wise from among the plurality of bit groups of the LDPC codeword, according to the number of columns constituting the block interleaver 124, the number of bit groups constituting the LDPC codeword, and the number of bits constituting each bit group.
In each of the plurality of columns, the second part may be formed of rows excluding as many rows as the number of bits included in at least some bit groups which can be written in each of the plurality of columns in bit group wise. Specifically, the number rows of the second part may be the same value as a quotient when the number of bits included in all bit groups excluding bit groups corresponding to the first part is divided by the number of columns constituting the block interleaver 124. In other words, the number of rows of the second part may be the same value as a quotient when the number of bits included in the remaining bit groups which are not written in the first part from among bit groups constituting the LDPC codeword is divided by the number of columns.
That is, the block interleaver 124 may divide each of the plurality of columns into the first part including as many rows as the number of bits included in bit groups which can be written in each column in bit group wise, and the second part including the other rows.
Accordingly, the first part may be formed of as many rows as the number of bits included in bit groups, that is, as many rows as an integer multiple of M. However, since the number of codeword bits constituting each bit group may be an aliquot part of M as described above, the first part may be formed of as many rows as an integer multiple of the number of bits constituting each bit group.
In this case, the block interleaver 124 may interleave by writing and reading the LDPC
codeword in the first part and the second part in the same method.
Specifically, the block interleaver 124 may interleave by writing the LDPC
codeword in the plurality of columns constituting each of the first part and the second part in a column direction, and reading the plurality of columns constituting the first part and the second part in which the LDPC codeword is written in a row direction.
That is, the block interleaver 124 may interleave by writing the bits included in at least some bit groups which can be written in each of the plurality of columns in bit group wise in each of the plurality of columns of the first part serially, dividing the bits included in the other bit groups except the at least some bit groups and writing in each of the plurality of columns of the second part in a column direction, and reading the bits written in each of the plurality of columns constituting each of the first part and the second part in a row direction.
In this case, the block interleaver 124 may interleave by dividing the other bit groups except the at least some bit groups from among the plurality of bit groups based on the number of columns constituting the block interleaver 124.
Specifically, the block interleaver 124 may interleave by dividing the bits included in the other bit groups by the number of a plurality of columns, writing each of the divided bits in each of a plurality of columns constituting the second part in a column direction, and reading the plurality of columns constituting the second part, where the divided bits are written, in a row direction.
That is, the block interleaver 124 may divide the bits included in the other bit groups except the bit groups written in the first part from among the plurality of bit groups of the LDPC
codeword, that is, the bits in the number of bit groups which correspond to the remainder when the number of bit groups constituting the LDPC codeword is divided by the number of columns, by the number of columns, and may write the divided bits in each column of the second part serially in a column direction.
For example, it is assumed that the block interleaver 124 is formed of C
number of columns each including R1 number of rows. In addition, it is assumed that the LDPC
codeword is formed of Ngroup number of bit groups, the number of bit groups Ngroup is not a multiple of C, and Ax C +1= Ngroup (A is an integer greater than 0). In other words, it is assumed that when the number of bit groups constituting the LDPC codeword is divided by the number of columns, the quotient is A and the remainder is 1.
In this case, as shown in FIGs 10 and 11, the block interleaver 124 may divide each column into a first part including R1 number of rows and a second part including R2 number of rows. In this case, R1 may correspond to the number of bits included in bit groups which can be written in each column in bit group wise, and R2 may be R1 subtracted from the number of rows of each column.
That is, in the above-described example, the number of bit groups which can be written in each column in bit group wise is A, and the first part of each column may be formed of as many rows as the number of bits included in A number of bit groups, that is, may be formed of as many rows as Ax M number.
In this case, the block interleaver 124 writes the bits included in the bit groups which can be written in each column in bit group wise, that is, A number of bit groups, in the first part of each column in the column direction.
That is, as shown in FIGs. 10 and 11, the block interleaver 124 writes the bits included in each of bit group Yo, bit group Yi, ..., group Y,k_i in the 1St to Rith rows of the first part of the 1st column, writes bits included in each of bit group YA, bit group YA4-1, = = bit group Y2A-1 in the 1st to Rith rows of the first part of the 2nd column, ..., writes bits included in each of bit group YCA-A5 bit group YcA_A+1, ..., bit group YcA4 in the 1st to Rith rows of the first part of the column C.
As described above, the block interleaver 124 writes the bits included in the bit groups which can be written in each column in bit group wise in the first part of each column.
In other words, in the above exemplary embodiment, the bits included in each of bit group (Yo), bit group (Y1),..., bit group (YA_i) may not be divided and all of the bits may be written in the first column, the bits included in each of bit group (YA), bit group (YA+1),..., bit group (Y2A-1) may not be divided and all of the bits may be written in the second columnõõ
and the bits included in each of bit group (YcA.A), bit group (YcA-A+1),... , group (YcA4) may not be divided and all of the bits may be written in the C column. As such, all bit groups interleaved by the first part are written in the same column of the first part.
Thereafter, the block interleaver 124 divides bits included in the other bit groups except the bit groups written in the first part of each column from among the plurality of bit groups, and writes the bits in the second part of each column in the column direction. In this case, the block interleaver 124 divides the bits included in the other bit groups except the bit groups written in the first part of each column by the number of columns, so that the same number of bits are written in the second part of each column, and writes the divided bits in the second part of each column in the column direction.
In the above-described example, since A x C +1 =N group 7 when the bit groups constituting the LDPC codeword are written in the first part serially, the last bit group YNgroup_i of the LDPC
codeword is not written in the first part and remains. Accordingly, the block interleaver 124 divides the bits included in the bit group YNgroup-i into C number of sub bit groups as shown in FIG. 10, and writes the divided bits (that is, the bits corresponding to the quotient when the bits included in the last group (YNgroup-i) are divided by C) in the second part of each column serially.
The bits divided based on the number of columns may be referred to as sub bit groups. In this case, each of the sub bit groups may be written in each column of the second part. That is, the bits included in the bit groups may be divided and may form the sub bit groups.
That is, the block interleaver 124 writes the bits in the 1" to R2th rows of the second part of the 1" column, writes the bits in the 1" to R2th rows of the second part of the 2"1 column, ..., and writes the bits in the 1" to R2th rows of the second part of the column C. In this case, the block interleaver 124 may write the bits in the second part of each column in the column direction as shown in FIG. 10.
That is, in the second part, the bits constituting the bit group may not be written in the same column and may be written in the plurality of columns. In other words, in the above example, the last bit group (YNgroup-1) is formed of M number of bits and thus, the bits included in the last bit group (YNgroup_i) may be divided by M/C and written in each column. That is, the bits included in the last bit group (Y
, - Ngroup-1) are divided by M/C, forming M/C number of sub bit groups, and each of the sub bit groups may be written in each column of the second part.
Accordingly, in at least one bit group which is interleaved by the second part, the bits included in the at least one bit group are divided and written in at least two columns constituting the second part.
In the above-described example, the block interleaver 124 writes the bits in the second part in the column direction. However, this is merely an example. That is, the block interleaver 124 may write the bits in the plurality of columns of the second part in the row direction. In this case, the block interleaver 124 may write the bits in the first part in the same method as described above.

Specifically, referring to FIG. 11, the block interleaver 124 writes the bits from the 1st row of the second part in the 1st column to the 1st row of the second part in the column C, writes the bits from the 2n1 row of the second part in the 1st column to the 2nd row of the second part in the column C, ..., etc., and writes the bits from the RP row of the second part in the 1St column to the R2th row of the second part in the column C.
On the other hand, the block interleaver 124 reads the bits written in each row of each part serially in the row direction. That is, as shown in FIGs. 10 and 11, the block interleaver 124 reads the bits written in each row of the first part of the plurality of columns serially in the row direction, and reads the bits written in each row of the second part of the plurality of columns serially in the row direction.
Accordingly, the block interleaver 124 may interleave a part of the plurality of bit groups constituting the LDPC codeword in bit group wise, and divide and interleave some of the remaining bit groups. That is, the block interleaver 124 may interleave by writing the LDPC
codeword constituting a predetermined number of bit groups from among the plurality of bit groups in the plurality of columns of the first part in bit group wise, dividing the bits of the other bit groups and writing the bits in each of the columns of the second part, and reading the plurality of columns of the first and second parts in the row direction.
As described above, the block interleaver 124 may interleave the plurality of bit groups in the methods described above with reference to FIGs. 9 to 11.
In particular, in the case of FIG. 10, the bits included in the bit group which does not belong to the first part are written in the second part in the column direction and read in the row direction. In view of this, the order of the bits included in the bit group which does not belong to the first part is rearranged. Since the bits included in the bit group which does not belong to the first part are interleaved as described above, bit rrror rate (BER)/frame error rate (FER) performance can be improved in comparison with a case in which such bits are not interleaved.
However, the bit group which does not belong to the first part may not be interleaved as shown in FIG. 11. That is, since the block interleaver 124 writes and reads the bits included in the group which does not belong to the first part in and from the second part in the row direction, the order of the bits included in the group which does not belong to the first part is not changed and the bits are output to the modulator 130 serially. In this case, the bits included in the group which does not belong to the first part may be output serially and mapped onto a modulation symbol.
In FIGs. 10 and 11, the last single bit group of the plurality of bit groups is written in the second part. However, this is merely an example. The number of bit groups written in the second part may vary according to the total number of bit groups of the LDPC
codeword, the number of columns and rows, the number of transmission antennas, etc.
The block interleaver 124 may have a configuration as shown in tables 23 and 24 presented below:
[Table 23]
Nom= 64800 QM< 16 QAM 64 QAM 256 QAM 1024 QAM 4096 QAM"

Ai 32400 16200 10800 7920 6480 5400 [Table 24]

____________________ QPSF 16 QAM 64 QAM 256 QAM 1024 QAM 4096 QAM

1t2 180 90 180 225 180 270 Herein, C (or NO is the number of columns of the block interleaver 124, R1 is the number of rows constituting the first part in each column, and R2 is the number of rows constituting the second part in each column.
Referring to Tables 23 and 24, the number of columns has the same value as a modulation order according to a modulation method, and each of a plurality of columns is formed of rows corresponding to the number of bits constituting the LDPC codeword divided by the number of a plurality of columns.
For example, when the length Nidp, of the LDPC codeword is 64800 and the modulation method is 16-QAM, the block interleaver 124 is formed of 4 columns as the modulation order is 4 in the case of 16-QAM, and each column is formed of rows as many as R1+R2=16200(=64800/4). In another example, when the length Nidpe of the LDPC
codeword is 64800 and the modulation method is 64-QAM, the block interleaver 124 is formed of 6 columns as the modulation order is 6 in the case of 64-QAM, and each column is formed of rows as many as R1+R2=10800(=64800/6).

Meanwhile, referring to Tables 23 and 24, when the number of bit groups constituting an LDPC codeword is an integer multiple of the number of columns, the block interleaver 124 interleaves without dividing each column. Therefore, R1 corresponds to the number of rows constituting each column, and R2 is 0. In addition, when the number of bit groups constituting an LDPC codeword is not an integer multiple of the number of columns, the block interleaver 124 interleaves the groups by dividing each column into the first part formed of R1 number of rows, and the second part formed of R2 number of rows.
When the number of columns of the block interleaver 124 is equal to the number of bits constituting a modulation symbol, bits included in a same bit group are mapped onto a single bit of each modulation symbol as shown in Tables 23 and 24.
For example, when N1dpc=64800 and the modulation method is 16-QAM, the block interleaver 124 may be formed of four (4) columns each including 16200 rows. In this case, the bits included in each of the plurality of bit groups are written in the four (4) columns and the bits written in the same row in each column are output serially. In this case, since four (4) bits constitute a single modulation symbol in the modulation method of 16-QAM, bits included in the same bit group, that is, bits output from a single column, may be mapped onto a single bit of each modulation symbol. For example, bits included in a bit group written in the 1st column may be mapped onto the first bit of each modulation symbol.
In another example, when N1dpc=64800 and the modulation method is 64-QAM, the block interleaver 124 may be formed of six (6) columns each including 10800 rows. In this case, the bits included in each of the plurality of bit groups are written in the six (6) columns and the bits written in the same row in each column are output serially. In this case, since six (6) bits constitute a single modulation symbol in the modulation method of 64-QAM, bits included in the same bit group, that is, bits output from a single column, may be mapped onto a single bit of each modulation symbol. For example, bits included in a bit group written in the 1st column may be mapped onto the first bit of each modulation symbol.
Referring to Tables 23 and 24, the total number of rows of the block interleaver 124, that is, R1+R2, is Nidpc/C.
In addition, the number of rows of the first part, R1, is an integer multiple of the number of bits included in each group, M (e.g., M=360), and maybe expressed as LATgroup I C i> M and the number of rows of the second part, R2, may be Nmpc,/C-Ri. Herein, [N group icj is the largest integer below Ngroup/C. Since R1 is an integer multiple of the number of bits included in each group, M, bits may be written in R1 in bit groups wise.
In addition, when the number of bit groups of the LDPC codeword is not a multiple of the number of columns, it can be seen from Tables 23 and 24 that the block interleaver 124 interleaves by dividing each column into two parts.
Specifically, the length of the LDPC codeword divided by the number of columns is the total number of rows included in the each column. In this case, when the number of bit groups of the LDPC codeword is a multiple of the number of columns, each column is not divided into two parts. However, when the number of bit groups of the LDPC codeword is not a multiple of the number of columns, each column is divided into two parts.
For example, it is assumed that the number of columns of the block interleaver 124 is identical to the number of bits constituting a modulation symbol, and an LDPC
codeword is formed of 64800 bits as shown in Table 28. In this case, each bit group of the LDPC codeword is formed of 360 bits, and the LDPC codeword is formed of 64800/360(=180) bit groups.
When the modulation method is 16-QAM, the block interleaver 124 may be formed of four (4) columns and each column may have 64800/4(=16200) rows.
In this case, since the number of bit groups of the LDPC codeword divided by the number of columns is 180/4(=45), bits can be written in each column in bit group wise without dividing each column into two parts. That is, bits included in 45 bit groups which is the quotient when the number of bit groups constituting the LDPC codeword is divided by the number of columns, that is, 45x360(=16200) bits can be written in each column.
However, when the modulation method is 256-QAM, the block interleaver 124 may be formed of eight (8) columns and each column may have 64800/8(=8100) rows.
In this case, since the number of bit groups of the LDPC codeword divided by the number of columns is 180/8=22.5, the number of bit groups constituting the LDPC codeword is not an integer multiple of the number of columns. Accordingly, the block interleaver 124 divides each of the eight (8) columns into two parts to perform interleaving in bit group wise.
In this case, since the bits should be written in the first part of each column in bit group wise, the number of bit groups which can be written in the first part of each column in bit group wise is

22, which is the quotient when the number of bit groups constituting the LDPC
codeword is divided by the number of columns, and accordingly, the first part of each column has 22x360(=7920) rows. Accordingly, 7920 bits included in 22 bit groups may be written in the first part of each column.
The second part of each column has rows which are the rows of the first part subtracted from the total rows of each column. Accordingly, the second part of each column includes 8100-7920(.180) rows.
In this case, the bits included in the other bit groups which have not been written in the first part are divided and written in the second part of each column.
Specifically, since 22x8(=176) bit groups are written in the first part, the number of bit groups to be written in the second part is 180-176 (=4) (for example, bit group Y1765 bit group Y177, bit group Y178, and bit group Y179 from among bit group Yo, bit group Yi, bit group Y2, = = =, bit group Y178, and bit group Y179 constituting the LDPC codeword).
Accordingly, the block interleaver 124 may write the four (4) bit groups which have not been written in the first part and remains from among the groups constituting the LDPC codeword in the second part of each column serially.
That is, the block interleaver 124 may write 180 bits of the 360 bits included in the bit group Y176 in the 1st row to the 180th row of the second part of the 1st column in the column direction, and may write the other 180 bits in the 1st row to the 180th row of the second part of the 2nd column in the column direction. In addition, the block interleaver 124 may write 180 bits of the 360 bits included in the bit group Y177 in the 18t row to the 180th row of the second part of the 31d column in the column direction, and may write the other 180 bits in the rt row to the 180th row of the second part of the 4th column in the column direction. In addition, the block interleaver 124 may write 180 bits of the 360 bits included in the bit group Y178 in the 1st row to the 180th row of the second part of the 5th column in the column direction, and may write the other 180 bits in the 1st row to the 180th row of the second part of the 6th column in the column direction. In addition, the block interleaver 124 may write 180 bits of the 360 bits included in the bit group Y179 in the 1st row to the 180th row of the second part of the 7th column in the column direction, and may write the other 180 bits in the 1st row to the 180th row of the second part of the 8th column in the column direction.
Accordingly, the bits included in the bit group which has not been written in the first part and remains are not written in the same column in the second part and may be divided and written in the plurality of columns.

Hereinafter, the block interleaver 124 of FIG. 5 according to an exemplary embodiment will be explained in detail with reference to FIG. 12.
In a group-interleaved LDPC codeword (vo, v1, ..., _,), Irj is continuously arranged like V={Yo, Yt, = = = YN -1.} =
W.2gP
The LDPC codeword after group interleaving may be interleaved by the block interleaver 124 as shown in FIG. 12. In this case, the block interleaver 124 divide a plurality of columns into the first part(Part 1) and the second part(Part 2) based on the number of columns of the block interleaver 124 and the number of bits of bit groups. In this case, in the first part, the bits constituting the bit groups may be written in the same column, and in the second part, the bits constituting the bit groups may be written in a plurality of columns(i.e. the bits constituting the bit groups may be written in at least two columns).
Specifically, input bits vi are written serially from the first part to the second part column wise, and then read out serially from the first part to the second part row wise. That is, the data bits v, are written serially into the block interleaver column-wise starting in the first aprt and continuing column-wise finishing in the second part, and then read out serially row-wise from the first part and then row-wise from the second part. Accordingly, the bit included in the same bit group in the first part may be mapped onto a single bit of each modulation symbol.
In this case, the number of columns and the number of rows of the first part and the second part of the block interleaver 124 vary according to a modulation format and a length of the LDPC codeword as in Table 25 presented below. That is, the first part and the second part block interleaving configurations for each modulation format and code length are specified in Table 25 presented below. Herein, the number of columns of the block interleaver 124 may be equal to the number of bits constituting a modulation symbol. In addition, a sum of the number of rows of the first part, N11 and the number of rows of the second part, Nr2, is equal to Nidpc/Nc (herein, Nc is Ogroup /Nd x 360 the number of columns). In addition, since Nri(= )is a multiple of 360, a multiple of bit groups may be written in the first part.
[Table 25]

Rows in Part 1 No Rows in Part 2 Nr2 Modulation Columns Nc Roc =64800 Nidpc =16200 Nicipc = 64800 Nidpc =16200 Hereinafter, an operation of the block interleaver 124 will be explained in detail.
Specifically, as shown in FIG. 12, the input bit v, (0 i <N, xN,i) is written in r, row of q i column of the first part of the block interleaver 124. Herein, q and r, are c, = - and r,=(i N
_ rl mod MO, respectively.
In addition, the input bit v, (Ncx111,ii <Nwpc) is written in r, row of q column of the second part of the block interleaver 124. Herein, q and r, satisfy c, = [(It -Nc x Nri)] and Nr2 r, = N, +{(i-NcxNõdmodN,2}, respectively.
An output bit qi(0.j<N1dpc) is read from q column of ri row. Herein, ri and q satisfy J
r' = [ ---. and c3=6 mod NO, respectively.
N, For example, when the length Nidpe of an LDPC codeword is 64800 and the modulation method is 256-QAM, the order of bits output from the block interleaver 124 may be (qopqi,q2,===04633579(163358,C163359,C1633601C163361,= = =,q64799)=
(VO,V7920)V15840)===0747519,V55439,V63359,V63360,V635401===3V64799)= Herein, the indexes of the right side of the foregoing equation may be specifically expressed for the eight (8) columns as 0, 7920, 15840, 23760, 31680, 39600, 47520, 55440, 1, 7921, 15841, 23761, 31681, 39601, 47521, 55441, ... , 7919, 15839, 23759, 31679, 39599, 47519, 55439, 63359, 63360, 63540, 63720, 63900, 64080, 64260, 64440, 64620, ... , 63539, 63719, 63899, 64079, 64259, 64439, 64619, 64799.
Hereinafter, the interleaving operation of the block interleaver 124 will be explained in detail.
The block interleaver 124 may interleave by writing a plurality of bit groups in each column in bit group wise in a column direction, and reading each row of the plurality of columns in which the plurality of bit groups are written in bit group wise in a row direction.
In this case, the number of columns constituting the block interleaver 124 may vary according to a modulation method, and the number of rows may be the length of the LDPC
codeword/the number of columns.
For example, when the modulation method is 16-QAM, the block interleaver 124 may be formed of 4 columns. In this case, when the length Nicipc of the LDPC codeword is 16200, the number of rows is 16200 (.64800/4). In another example, when the modulation method is 64-QAM, the block interleaver 124 may be formed of 6 columns. In this case, when the length Nicipc of the LDPC codeword is 64800, the number of rows is 10800 (.64800/6).
Hereinafter, the method for interleaving the plurality of bit groups in bit group wise by the block interleaver 124 will be explained in detail.
When the number of bit groups constituting the LDPC codeword is an integer multiple of the number of columns, the block interleaver 124 may interleave by writing the bit groups as many as the number of bit groups divided by the number of columns in each column serially in bit group wise.
For example, when the modulation method is 16-QAM and the length Niapc of the LDPC
codeword is 64800, the block interleaver 124 may be formed of four (4) columns each including 16200 rows. In this case, since the LDPC codeword is divided into (64800/360=180) number of bit groups when the length I=11dpc of the LDPC codeword is 64800, the number of bit groups (=180) of the LDPC codeword may be an integer multiple of the number of columns (=4) when the modulation method is 16-QAM. That is, no remainder is generated when the number of bit groups of the LDPC codeword is divided by the number of columns.
In this case, as shown in FIG. 13, the block interleaver 124 writes the bits included in each of the bit group Yo, bit group ...., bit group Y44 in the 1st row to 16200th row of the first column, writes the bits included in each of the bit group Y45, the bit group Y46, . .
. , the bit group Y89 in the 1st row to 162001h row of the second column, writes the bits included in each of the bit group Y90, the bit group Y91,..., the bit group Y134 in the 1st row to 16200th row of the third column, and writes the bits included in each of the bit group Y135, the bit group Y136,..., the bit group Y179 in the 1st row to 16200th row of the fourth column. In addition, the block interleaver 124 may read the bits written in each row of the two columns serially in the row direction.
In another, when the modulation method is 64-QAM and the length Nidp, of the LDPC

codeword is 64800, the block interleaver 124 may be formed of six (6) columns each including 10800 rows. In this case, since the LDPC codeword is divided into (64800/360=180) number of bit groups when the length Nidp, of the LDPC codeword is 64800, the number of bit groups (.180) of the LDPC codeword may be an integer multiple of the number of columns (=4) when the modulation method is 64-QAM. That is, no remainder is generated when the number of bit groups of the LDPC codeword is divided by the number of columns.
In this case, as shown in FIG. 14, the block interleaver 124 writes the bits included in each of the bit group Yo, bit group bit group Y29 in the 1st row to 108001h row of the first column, writes the bits included in each of the bit group Y30, the bit group the bit group Y59 in the 1st row to 10800th row of the second column, writes the bits included in each of the bit group Y60, the bit group the bit group Y89 in the 1st row to 10800th row of the third column, writes the bits included in each of the bit group Y90, the bit group Y91,..., the bit group Y119 in the 1st row to 10800th row of the fourth column, writes the bits included in each of the bit group Y1201 the bit group Y121,..., the bit group Y149 in the 1st row to 10800th row of the fifth column, and writes the bits included in each of the bit group Y150, the bit group Y151,..., the bit group Y179 in the I.st row to 10800th row of the sixth column.. In addition, the block interleaver 124 may read the bits written in each row of the two columns serially in the row direction.
As described above, when the number of bit groups constituting the LDPC
codeword is an integer multiple of the number of columns of the block interleaver 124, the block interleaver 124 may interleave the plurality of bit groups in bit group wise, and accordingly, the bits belonging to the same bit group may be written in the same column.
As described above, the block interleaver 124 may interleave the plurality of bit groups of the LDPC codeword in the method described above with reference to FIGs. 13 and 14.
The modulator 130 maps the interleaved LDPC codeword onto a modulation symbol.

Specifically, the modulator 130 may demultiplex the interleaved LDPC codeword, modulate the demultiplexed LDPC codeword, and map the LDPC codeword onto a constellation.
In this case, the modulator 130 may generate a modulation symbol using the bits included in each of a plurality of bit groups.
In other words, as described above, the bits included in different bit groups are written in each column of the block interleaver 124, and the block interleaver 124 reads the bits written in each column in the row direction. In this case, the modulator 130 generates a modulation symbol by mapping the bits read in each column onto each bit of the modulation symbol.
Accordingly, each bit of the modulation symbol belongs to a different bit group.
For example, it is assumed that the modulation symbol consists of C number of bits. In this case, the bits which are read from each row of C number of columns of the block interleaver 124 may be mapped onto each bit of the modulation symbol and thus, each bit of the modulation symbol consisting of C number of bits belong to C number of different bit groups.
Hereinbelow, the above feature will be described in greater detail.
First, the modulator 130 demultiplexes the interleaved LDPC codeword. To achieve this, the modulator 130 may include a demultiplexer (not shown) to demultiplex the interleaved LDPC
codeword.
The demultiplexer (not shown) demultiplexes the interleaved LDPC codeword.
Specifically, the demultiplexer (not shown) performs serial-to-parallel conversion with respect to the interleaved LDPC codeword, and demultiplexes the interleaved LDPC codeword into a cell having a predetermined number of bits (or a data cell).
For example, as shown in FIG. 15, the demultiplexer (not shown) receives the LDPC
codeword Q=(q0, qi, q2, ...) output from the interleaver 120, outputs the received LDPC
codeword bits to a plurality of substreams serially, converts the input LDPC
codeword bits into cells, and outputs the cells.
In this case, the bits having the same index in each of the plurality of substreams may constitute the same cell. Accordingly, the cells may be configured like (yo,o, yi,o, y1moD-1,0=(q0, qi, chmoD-1), (yo,i, yi,i, = = =, yilmoD-1,1)=( %mop, q040D+1, = = =, q2õm0D-1), . = ===
Herein, the number of substreams, Nsubstreams9 may be equal to the number of bits constituting a modulation symbol, ImoD. Accordingly, the number of bits constituting each cell may be equal to the number of bits constituting a modulation symbol (that is, a modulationorder).
For example, when the modulation method is 16-QAM, the number of bits constituting the modulation symbol, 11/9,40D, is 4 and thus the number of substreams, Nsubstreams, is 4, and the cells may be configured like (y0,0, Y1,09 Y2,09 Y3,0)=(:109 qi, (42, q3), (yo,i, yi,i, y2,1, y3,1)---(q4,q5, q6,q7), (Y0,29 Y1,29 Y2,29 y3,2)=(q8, q9, q10, qii), = = = =
In another example, when the modulation method is 64-QAM, the number of bits constituting the modulation symbol, imoD, is 6 and thus the number of substreams, Nsubstr., is 6, and the cells may be configured like (yo,o, Y1,09 Y2,09 Y3,09 Y4,09 Y5,0)4C109 qi, q2, q3, q4, q5), (yo,i, yi,i, Y2,19 Y3,19 Y4,1, Y5,1)=(q6,C177 q8,1:19, q10,c111), (Y0,2, Y1,25 Y2,25 Y3,25 Y4,25 Y5,2)=(q123 q13, q14, q15, q16, q17)/ = = ' =
The modulator 130 may map the demultiplexed LDPC codeword onto modulation symbols.
Specifically, the modulator 130 may modulate bits (that is, cells) output from the demultiplexer (not shown) in various modulation methods such as Quadrature Phase Shift Keying (QPSK), 16-QAM, 64-QAM, 256-QAM, 1024-QAM, 4096-QAM, etc. For example, when the modulation method is QPSK, 16-QAM, 64-QAM, 256-QAM, 1024-QAM, and QAM, the number of bits constituting the modulation symbol, iimoD (that is, the modulation order), may be 2, 4, 6, 8, 10 and 12, respectively.
In this case, since each cell output from the demultiplexer (not shown) is formed of as many bits as the number of bits constituting the modulation symbol, the modulator 130 may generate the modulation symbol by mapping each cell output from the demultiplexer (not shown) onto a constellation point serially. Herein, the modulation symbol corresponds to a constellation point on the constellation.
However, the above-described demultiplexer (not shown) may be omitted according to circumstances. In this case, the modulator 130 may generate modulation symbols by grouping a predetermined number of bits from interleaved bits serially and mapping the predetermined number of bits onto constellation points. In this case, the modulator 130 may generate the modulation symbols by mapping rimoD number of bits onto the constellation points serially according to a modulation method.
The modulator 130 may modulate by mapping cells output from the demultiplexer (not shown) onto constellation points in a non-uniform constellation (NUC) method.
In the non-uniform constellation method, once a constellation point of the first quadrant is defined, constellation points in the other three quadrants may be determined as follows. For example, when a set of constellation points defined for the first quadrant is X, the set becomes ¨
conj(X) in the case of the second quadrant, becomes conj(X) in the case of the third quadrant, and becomes ¨(X) in the case of the fourth quadrant.
That is, once the first quadrant is defined, the other quadrants may be expressed as follows:
1 Quarter (first quadrant)=X
2 Quarter (second quadrant)=-conj(X) 3 Quarter (third quadrant)=conj(X) 4 Quarter (fourth quadrant)=-X
Specifically, when the non-uniform M-QAM is used, M number of constellation points may be defined as z=lzo, z1, zm_11. In this case, when the constellation points existing in the first quadrant are defined as {xo, xi, x2, ..., xm/44}, z may be defined as follows:
from zo to zmi41=from xo to Xm/4 from Zh4/4 to zam/4-1=-conj(from xo to xm/4) from Z2x4g to z3xM/4-1=COnKfrOM x0 to XM/4) from zwot to Z4xM/4-1=-(from xo to xm/4) Accordingly, the modulator 130 may map the bits [yo, ..., y.4] output from the demultiplexer (not shown) onto constellation points in the non-uniform constellation method by mapping the output bits onto ZL having an index of L = (y1 x 2m1). An example of the constellation i=0 defined according to the non-uniform constellation method may be expressed as in tables 26 to 30 presented below when the code rate is 5/15, 7/15, 9/15, 11/15, 13/15:
[Table 26]
Input data cell y Constellation point z, (00) (1+10/4T
(01) (1 -11)/4T
(10) (-1+10/4r (11) (-1-14/.1F
[Table 27]
xi Olaf* aiitis 015 33115 3331/3 fk0/15 wits Invis rnvis no 0.4330+3.26531 i21um.sozai 0,4813+3,25751 3,41509+1.20071 02173+041031 11,3031+045471 0.2995+4.29591 05517+035111 0.16614A5301 0.3014+1.21021 OM-75+001M 1.2007+0.49091' 1316711+0.25711 0.0917+0.20001 0.954114.2936X 0.3531+3.33611 x2 1.7002+3.51131 0.0100.211241 1.2000A0511 3.207640-30031, 34333423031 0.2121+040301 0-230+34301 0-3007401324 x3 (0.5115.1.23921 0.2621=11,05171 3455,01.211611 3,305.30.L31731 1,2083+05E011 11,29050.21271 64500+3.53401 0,3301+0,33571 [Table 28]
Lx/Shape I 13164.003 4041,,,V13 assjen 9/I5 R64_10/15 ...F464.73/.15 _It#1..1745 5103..1388 ! (6õ0367.1.00331, 0.3351+110arsu 14827.0,29201 , 413347411.51451 1A363+012761 0.3317Ø66701 1.0154,10,33941 04.100+0.74731 xx. I1.6023041-4,3671 0.8777Ø65041 1.Z46010.114111 6.1681Ø68421 imscosetaa 111318081,3241, 0.7308Ø4623k 0.1349+0.33314 x2 ! 06r13+3.43311 0.1.11.10170iti L3213Ø23./At , tai4110.2701, 10 .03+3,2219i1 0.10Ziotosmth, .4.004+0 0 42,0 .1051 0.-70+3t xXs 1,06611.41.87031 ' 0.230+0,3003i cifxse0.3702o =0,3330Ø37004 110484.1.3.81401C 011804.1,13,721,õ
0.72,4340150,41- 012300.160W
I 0,2202+342101 0Ø100,3$151 3.2120+13017$ 34177+0,0101 , 02531=1465611 .0,5332+13.4.9301' Loontemoto 0A85+0,0174 ' I 0,1019033161 0,65770.2.0841' ...,t41041,2301 dt3142+0,17561, 0.821091õ22731 0.67230.1335P. 376720407N
30430.3019ii , in6 111.3049+0460011 03071.017111 V.Z170.1,03131 9.70404017361'. 0.200394,084911. 3,35370,14011, 1A2.110,20 01.
V56070.13611 02003.17346+612061 6.576140,67601 0-3771.-0.11481 -0.6774080-71i 0.3040Ø32041 01111,3510.17631 83994Ø13004 0.7018,1120191 0.0800Ø69726 0.3040,41114731, .2363941.811441 0.411.9Ø1177i 0.6034.089221 01962Ø40701 0.7260-4.1120111 ' 0.93.33Ø72181 0.2353.1.01401 &'c*1I4t101L cuoaaamm 0369802316.
I 3.2.1.30r.L9zat 0.4181,-0,92,031 3_0483.D949Si K10. I 0,.734188.26531, 03430.1.26191 41,8365=01.11731 , 8199+1.74101 0.7441.43-13831- 0.9394.1177141 01407.013361 01968.1.77331 611 00454Ø30691 0.2603.1.48344 8.4013690.36661 11.310otA6311 0,5n4Pxx4x3er 0.5{41.145,051, qAzas+gu an!
0.550741,479,11 I 0007018,34791 ' 0.690f8,000041' ' 0-1470/000464 8,6604=0604651 0,1105+016701 11,007+043731 01200+0,79070 090010.51,40x ' 435, ! 02171+326751 1.01170,23501 $,1091+0.30031 14102+0.2101 315120.025V ' 9.9739049501 0.4197*072061 1.3100,502V
44, 1 0,2090.3.27311 1.2621104070 0:317140.313011 1.210+0.04161 .. 0,13160.7x381 .. 1.2210+0.6701 .. 0.13$241.01.01 ..
041,76+0.17161 810 0,71161.823901 _ 1,63941Ø193.21 11...300040.01161 1.41191340.29731, 0,37.174,0.07001 1.38644A 73231 0.2261441.30141.
1.44124019440 [Table 29]

x/Shape NUC_64 005 NM 64 7/15 NUL 64 Elvis MX 9/15 INUIL64 10/15 KUC 60 11/15 NUL 64_12/11.5 101,1C_64 x0 13.4387+1.60231 0.335240.60281 , 1,41827Ø252011 0.3547+0.61491 143884.28781 03317+0.6970 108544.53941 .. 0.8624 + 1.17151 xl 14023443871 0.20774.65841 1.25634.84111 0.15814.68421 11150.081331 0.1386403241 0.7353+046231 1.1184 Ø84621 4 08753+1.0888 01711.030281 111211+0.21741 015674.27491 10385+012191 0.1323Ø44371 10474+016951 0.2113 . 1.38431 x3 108814.87531 0355640,30351 0.87984.57021 0.1336.037001 0.8494+0.61451 0.1015413721 0.724340.15041 07535+0.77071 x4 0.2202+0.92381 0602840.33451 0.29204148271 0617740.40301 02932+146561 05682Ø4500 10693+0.94091 .. 1.1796 Ø16611 x5 , 023194.781.81 0.6577Ø20841 õ 0.8410+1.25631 0.7262Ø17561 0.8230+1.22781 0.67394.14351 0.7092+0.80731 1.0995+0.19921 16 0.30494.84.541 0.302140.17111 0.2174+1.02111 03568+0.17561 0.2069441.06491 0.3597+0.34011 1.42614.22161 08101 0.14921 x7 0.255340.75401 0.302840.15561 ' 0.5702+0.87981 0.3771+0,13361 0,5677.0 29711 0_3660+0.12041 04106+1.1783i .. 07482 . 044771 0.78/8+01019i 0.55564.89221 0.304040.147 0.5639.4.88641 0.4119441.11771 0.600440.89221 01392+0.40781 0.1524 + 0.9943i //9 0.9238Ø2200 0.235241,01906 0.302840.16911 0.1980+1.02771 0.399840.25161 0.21204122531 0,4262+0.42051 01482 + 0.68771 10 1175404.26531 0.945041.26191 0.6855Ø18711 0.8199.1.23151 _0.74424.15591 0.9594+107241 0.1,4074.13361 0,4692 . 1.08531 41 0.84544.30491 0292241.48941 0.612640.35631 0.2854+14691/ 0se54so.43291 03829*1.3995 0.4265Ø13881 04492 + 0.73531 x12 01675.024791 0.8929+055491 014754.31310 016564.60581 01166+0.16781 11843940-56751 0.13884.7135,71 0.1579+0.13191 x13 02479+0.26751 1.019(74.23591 0.16914030291 1.038240.21411 015824033151 0.97594.19593 0.4197+0.72061 0.14634 0.40251 x14 0.2890+02701i 1.2626+0,84571 0.187140.68551 1.23624084191 0.1355414081 122394067601 01682.1.03161 04163+0.14071 0.2701+0.28901 1.48944.29221 03553+0.61251 1.1663s0.29733 0.372144.621301 135534013231 0.77874139141 04411 49.42611 [Table 30]

x /Shape 06/15 67/15 101/15 89/15 1110/15 011/15 0.6800+1.69261 1.2905+1.3099 1.080441.37881 1.323141.15061 1.609140.15481 0.310540.33821 1.101441.16701 0.355640.34971 41 0.391181.36451 1.0504Ø95771 1.048740.98621 0.9851+1.23111 1554940.46051 0.43424.33601 0.855741/4211 0.35794.49451 82 0.2191+1.7524i 1.532940.89351 1.6464+0.74281 1.14394.89741 1.3226Ø12901 0.314940.48291 1.295740.80391 0.5049Ø35711 83 0.2274+14208i 1.15774.81161 1.324540.94141 0.9343+0.92711 1.2772033291 0.4400Ø48071 1.08810.89561 0.505610.50631 x4 0.8678.1.24871 1.78814.2509 0.7198+1.24271 1.53984.79621 1.2753+102421 0.181140.13751 0.579541.21101 0.212340.34971 45 0.727581.16671 1.4275+0.14001 0.810641.0049 0.90924.55991 1.4434+0.75401 0.06334.34041 0.6637+1.4219 0.211640.49001 xe 0.8747+1.04701 1.4784Ø52011 0.559541.03171 1.222240.65741 1.04910.84761 0.181840.48511 0.693041.00821 0.07134.34891 47 0.7930+1.04061 1.3408+0.43461 0.611840.97221 0.957940.63731 1.186140.62531 0.063340.48151 0.884940.96471 0.06904.49601 0209840.97681 0.7837+0.58671 1.676840.20021 0.7748+1.58671 0.932640.09701 0.30844.19711 1.2063+0.51151 0.352740.20861 .9 0.2241+1.04541 0025040.64551 0999740.68441 0.6876+1.24891 0.8962+0.28041 0.43564.19931 1.005940,49521 0.34974.07131 810 0.185E10.98781 0.825640.56011 1.421240.47691 059924.92081 1.104440.11021 0.309840.05761 1.417140.59011 0.496040.21231 .11 0.190181.06591 0.87774.61101 1.147940.63121 0.679640.9740 1.0648+031671 0.434240.06911 1.046640.69351 0.49744.06961 .12 0.5547+0.83121 1.0080+0.18431 0.6079Ø6569 0.58364.58791 0.73250.60711 0.1775+0.19851 0.66394.62861 0.208640.2079 413 17547940.86511 1.0759+0.17211 0.72844.69571 0.69154.57691 0.82604.45591 0.06404.19781 0.8353Ø58511 0.209440.06901 .14 0.6073+0.81821 1.0056+0.27581 0.5724,0.70311 0.58584.70581 0.3744.10.71531 0.1775+0.06761 0.687940.80221 0.067640.20791 x15 0.595540.84201 1.06624.29641 0.630240.72591 0.6568+0.67931 0.988240.53001 006474.06691 0.863440.76221 0.069840.0689 .16 1.407040.17901 0.8334+1.55541 0.1457+1.40101 1.6118+0.14971 0.1646+1.64071 0.7455.034111 0.1213+1.43661 0.35864.79591 817 1.7227+0/9001 00165+1.10921 0.186641.73461 0.951140.11401 0.4867+1.57431 0,581140.3399 0.1077.1.20981 0.357140.63921 818 1.324640.25621 0.6092+1.27291 0.117441.10351 1.297040.12341 0.1363+1.3579 0.755640.46691 0.065140.98011 0.50344.8270 819 1.36354.36541 0.6728.1.14561 01095.1.01321 1.0266Ø1195 0.4023+130261 0.5862+0.47561 0.200941.01151 0.5063+0.66001 520 1.370341.28341 0.3061+1.74691 0.4357.1.36361 1.53314.44961 1.0542+1.25841 0.95564.32801 0.3764+1.42641 0.214610.78621 821 1.610140.84031 0.1327+1.40561 0.5853+1.68201 0.93284.35861 0.7875.1.44501 1.176740.30911 0.3237+1.2139 0.21094.63401 .22 1.161440.79091 0.3522+1.34141 0.343941.06891 1.27964.38941 0.8687+1.04071 0.967340.47201 0.520540.98141 0.07134.80931 .23 1.224140.73671 0.2273+1.30811 0.323440.99621 1.01880.34471 0.6502.1.19511 1.2051+0.51351 0.361541.01631 0.069840.64671 624 0376340.18631 0,5007Ø80981 0109240.61741 0594040.10591 0.098240.97451 0736740.20151 0.071540.65961 0.279944.08621 825 0.945249.20571 0.5528+1183471 0.107440.63071 012154.11901 0.28420.93441 0.581140.20151 0.211640.65971 0.2806+1.27551 x26 1.0100Ø21821 0.484340.84861 0.110940.69961 0,5863Ø1139 0.1142+1.14481 0.7316+0.06591 0.072940.8130 0.432840.99041 .27 0.979540.24171 0.530440.87591 0.107640.73451 0.6909+0.11661 0.3385+1.09731 0.57824.06691 0.215840.82461 0.45510.18121 .28 032414048561 0.171540.91471 0.329110.62641 0.5843+0.36041 0.6062Ø74651 0.906240.19711 0.503640.64671 0.23090.94141 .29 0023240.48371 0.15400.9519 0312640.63731 0.69704.35921 0.460740.85381 1.28294.11851 0.352640.65721 01077+1.38911 .30 0.879940.53911 0.19644.94381 0.3392+0.69991 0S808+0.3250 0.72634.87641 0.91564.07351 0.518540.80861 0.077240.98521 831 0.87960.53561 0.17884.98321 0.3202+0.72821 00678432901 0.5450+1.00671 1101103.07351 0.35934.82451 0.0802.1.17531 x32 0.137640.33421 0.375240.16671 0.965240.10661 0.14060.61821 0.265540.07461 0.3244+0.80441 12545401010I
0.8301Ø37271 .33 0.138340.32921 0.3734Ø16671 0.9075+0.16661 0.1272.129841 0.266440.07591 0.4589+0.82181 1.06764.09561 0.825640.52561 439 0.136340.33221 0375840.1661/ 0.972440.11711 0.1211+09640 0.4571+0.08521 032074.6415/ 1.4792Ø11671 0.6593,036681 135 0.137040.32731 0.374640.16491 0.918640.17521 0.1220+1.03931 0.451640.1060 0,45090.63711 0.398140.08821 0,6623+0.51821 x36 0.165540.32651 0.4013Ø12301 0.63420.13721 0.11244061011 0.255940.17901 0.192040.81961 0.55180.06901 1.01864.36491 x37 0.16564.32271 0.4001+0.12301 0.6550Ø14951 0.117740.60411 0.2586+0.17721 00633+0.81671 0.6903+005521 1.0001452421 x38 0.163440.32461 0.403740.12301 0.629010.13931 0.1136+0.74551 0.35920.28111 013114.63711 0.5740+019871 1.185740.27251 .39 0.163640.32081 0.401940.1219 0.6494+015041 0.118540.7169 0.372840.26541 0.06404064151 0.73740.15641 1.39290.34081 x40 0.177940.68411 0.60254.39341 1312740.12401 0.4324+1.56791 0.770640.09221 03331+1.06691 1.237840.30491 0.80114.22271 .41 0.1828+0.68451 0.59464.39281 0.9572+0.43441 0.39134+1.28251 0.7407+0.22601 04655+1.00871 1.0518+0.30321 0.79814.0739 442 0174540.68281 0.611640.38791 1.2403+0.26311 0.3766+0.95341 0.618040.09271 034334128651 1.458440.35111 06459+0.21981 .43 0.179340.68291 0.60194.38371 1.0254Ø41301 113568.1.03011 0.601940.1650 0.5004+1.50621 0.910740.26031 0.643040.07131 .44 0.354740.60091 0.7377+0.1610 0.6096+0.42141 0.36670.59951 0.600740.49801 0.1971.1.00511 0.632/Ø47291 0.96814.22051 145 0.359340.60111 0.72984.15821 0.6773Ø42841 0.332840.59601 0.66730.39231 0.0735+1.02981 0.7880+0.43921 0.961540.07351 x46 0.357640.59901 0.727440.17821 0.5995+0.41021 0.35874.71941 0.478640.39351 01498+1.50181 0.60450.32741 1.33274.10391 .47 0.362440.59941 0.716544117461 0.653140.4100 0.3373+0.69641 0.517640.33911 0.086541.25531 0.76294.29651 1.135940.08091 x48 0.26974014431 0.150940.24251 0.125040.11531 0.106540.11461 0.0757+0.10031 0.781140.80801 0.059640.07391 0.838240.87091 .49 0.070440.14331 0,15034.24001 0.125240.11581 0.114540.11081 0.075340.10041 0.6/6740.81531 0.176740.0730 0.814540.69341 .50 0.264403.14421 0.15154.24371 0.124540.11521 0.105340.12741 0.077740.47881 0.76364.62551 0.061240.21981 0.664540.84861 .51 0.2650+014321 0150340.24251 0.1247+0.11561 0.11340.12361 0.086740.47541 0,60004.6320 0.181540.21921 0.6600Ø67861 152 0.276340.16381 0.1285Ø2389 0.376840.12441 0.111140.38211 0.102340.22431 0.989880.76801 0.42184007151 1.16120.69491 x53 3.276840.16261 0,12794.24191 0.3707+0.12371 01186+038671 0.101040.22421 1.58550.14981 0.297840.07251 0.978540.69421 x54 0.271540.16301 0.12794.24311 0.377940.12601 0.10804.34311 0.195040.39191 0.947640.6179 0.4337+0.21151 1369840.62591 .55 0.271940.16181 0.12794.24061 0.37170.12521 0.117740.34591 0.188140.39691 1.462540.40151 0.305740.21671 1.2111341.48411 456 0.648840.16961 0.339440.57641 0.116140.36931 03644+0.10801 0.093040.81221 0.8276+1.02251 0.066780.51241 07989+104981 .57 0.646240.17061 0.33644.57221 0.115740.36451 0.3262+0.11041 0.2215+0.78401 0.631341.03641 0.2008+0.50951 0.4395+1.42031 x58 0.64564.17451 033284.575E11 0.11760.34691 0.3681+0.11131 0.093740.65141 0.88154128651 0.062540.36581 0.6118+1.02461 859 0.643140.17531 0.3303+0.56981 0.1171+0.34241 0.3289+0.11961 0.1540+0.63661 0.6342+1.27051 0.189940.35421 0.6303+1.24211 x60 0.585440.31861 0.1491+0.63161 0.3530Ø38991 0.366540.37581 0.481040.6300 1.0422+0.95931 0081840.49461 1,055040.89241 x61 0586240.31671 01461Ø62501 0.3422+0.38081 0.3310+0.3799 0.385640.70371 1.27494.85381 0.338040.50501 0.861241.28001 .62 0.5864032751 0.15094.62801 0.3614+0.37551 0.36790.33531 0.3527+0.52301 11556+1.18471 0.457140.34991 1.269640.89691 x63 0.587340.32541 0.147340.62251 0.3509Ø36561 0333610.34021 0.310040.55591 1.4771+067421 0.321640.35991 1.0342.1.11811 Table 26 indicates non-uniform QPSK, table 27 indicates non-uniform 16-QAM, Tables 28 and 29 indicate non-uniform 64-QAM, and table 30 indicates non-uniform 256-QAM.
Referring to these tables, the constellation point of the first quadrant may be defined with reference to tables 26 to 30, and the constellation points in the other three quadrants may be defined in the above-described method.
However, this is merely an example and the modulator 130 may map the output bits outputted from the demultiplexer (not shown) onto the constellation points in various methods.
The interleaving is performed in the above-described method for the following reasons.
Specifically, when the LDPC codeword bits are mapped onto the modulation symbol, the bits may have different reliability (that is, receiving performance or receiving probability) according to where the bits are mapped onto in the modulation symbol. The LDPC codeword bits may have different codeword characteristics according to the configuration of a parity check matrix. That is, the LDPC codeword bits may have different codeword characteristics according to the number of 1 existing in the column of the parity check matrix, that is, the column degree.
Accordingly, the interleaver 120 may interleave to map the LDPC codeword bits having a specific codeword characteristic onto specific bits in the modulation symbol by considering both the codeword characteristics of the LDPC codeword bits and the reliability of the bits constituting the modulation symbol.
For example, when the LDPC codeword formed of bit groups X0 to X179 is group-interleaved based on Equation 21 and Table 11, the group interleaver 122 may output the bit groups in the order of X55, X146, X83, - = ., X132, X135.
In this case, when the modulation method is 16-QAM, the number of columns of the block interleaver 124 is four (4) and each column may be formed of 16200 rows.
Accordingly, from among the 180 groups constituting the LDPC codeword, 45 bit groups (X55, X146, X83, X52, )(62, X176, X160, X68, X53, X56, X81, X97, X79, X113, X163, X61, X58, X69, X133, X108, X66, X71, X86, X144, X57, X67, X116, X59, X70, X156, X172, X65, X149, X155, X82, X138, X136, X141, Xi I 1, X96, X170, X90, X140, X64, X159) may be inputted to the first column of the block interleaver 124, 45 bit groups (X15, X14, X37, X54, X44, X63, X43, X18, X47, X7, X25, X34, X29, X30, X26, X39, X16, X41, X45, X36, X0, X23, X32, X28, X27, X38, X48, X33, X22, X49, X51, X60, X46, X21, X4, X3, X20, X13, X50, X35, X24, X40, X17, X42, X6) may be inputted to the second column of the block interleaver 124, 45 bit groups (X112, X93, X127, X101, X94, X115, X105, X31, X19, X177, X74, X10, X145, X162, X102, X120, X126, X95, X73, X152, X129, X174, X125, X72, X128, X78, X171, X8, X142, X178, X154, X85, X107, X75, X12, X9, X151, X77, X117, X109, X80, X106, X134, X98, Xi) may be inputted to the third column of the block interleaver 124, and 45 bit groups (X122, X173, X161, X150, X110, X175, X166, X131, X119, X103, X139, X148, X157, X114, X147, X87, X158, X121, X164, X104, X895 X179, X123, X118, X99, )(88, X11, X92, X165, X84, X168, X124, X169, X2, X130, X167, X153, X137, X143, X91, X100, X5, X76, X132, X135) may be inputted to the fourth column of the block interleaver 124.
In addition, the block interleaver 124 may output the bits inputted to the 1st row to the last row of each column serially, and the bits outputted from the block interleaver 124 may be inputted to the modulator 130 serially. In this case, the demultiplexer (not shown) may be omitted or the bits may be outputted serially without changing the order of bits inputted to the demultiplexer (not shown). Accordingly, the bits included in each of the bit groups X55, X15, X112, and X122 may constitute the modulation symbol.
When the modulation method is 64-QAM, the number of columns of the block interleaver 124 is six (6) and each column may be formed of 10800 rows.
Accordingly, from among the 180 groups constituting the LDPC codeword, 30 bit groups (X55, X146, X83, X52, X62, X176, X160, X68, X53, X56, X81/ X97, X79, X113, X163, X61, X58, X69, X133, X108, X66, X71, X86, X144, X57, X67, X116, X59, X70, X156) may be inputted to the first column of the block interleaver 124, 30 bit groups (X172, X65, X149, X155, X82, X138, X136, X141, X111, X96, X170, X90, X140, X64, X1595 X15, X14, X37, X54, X44, X63, X435 X18, X47, X7, X25, X34, X29, X30, X26) may be inputted to the second column of the block interleaver 124, 30 bit groups (X39, X16, X41, X45, X36, X0, X23, X325 X28, X27, X38, X48, X33, X22, X49, X51, X60, X46, X21, X4, X3, X20, X13, X50, X35, X24, X40, X17, X42, X6) may be inputted to the third column of the block interleaver 124, 30 bit groups (X112, X93, X127, X101, X94, X115, X105/ X31, X19, X177, X74, X10, X145, X162, X1025 X120, X126, X95, X73, X152, X129, X174, X125, X72, X128, X78, X171, X8, X142, X178) may be inputted to the fourth column of the block interleaver 124, 30 bit groups (X154, Xs5, X107, X75, X12, X9, X151, X77, X117, X109, X80, X106, X134, X98, X1, X122, X173, X161, X150, X110, X175, X166, X131, X119, X103, X139, X148, X157, X114, X147) may be inputted to the fifth column of the block interleaver 124, and 30 bit groups (X87, X158, X121, X164, X104, X89, X179, X123, X118, X99, X88, X11, X92, X165, )(84, X168, X124, X169, X2, X130, X167, X153, X137, X143, X91, X100, X5, X76, X132, X135) may be inputted to the sixth column of the block interleaver 124.
In addition, the block interleaver 124 may output the bits inputted to the 1.8' row to the last row of each column serially, and the bits outputted from the block interleaver 124 may be inputted to the modulator 130 serially. In this case, the demultiplexer (not shown) may be omitted or the bits may be outputted serially without changing the order of bits inputted to the demultiplexer (not shown). Accordingly, the bits included in each of the bit groups X55, X172, X39, X112, X154 ,and X87 may constitute the modulation symbol.
As described above, since a specific bit is mapped onto a specific bit in a modulation symbol through interleaving, a receiver side can achieve high receiving performance and high decoding performance.
That is, when LDPC codeword bits of high decoding performance are mapped onto high reliability bits from among bits of each modulation symbol, the receiver side may show high decoding performance, but there is a problem that the LDPC codeword bits of the high decoding performance may not be received. In addition, when the LDPC codeword bits of high decoding performance are mapped onto low reliability bits from among the bits of the modulation symbol, initial receiving performance is excellent, and thus, overall performance is also excellent.
However, when many bits showing poor decoding performance are received, error propagation may occur.
Accordingly, when LDPC codeword bits are mapped onto modulation symbols, an LDPC
codeword bit having a specific codeword characteristic is mapped onto a specific bit of a modulation symbol by considering both codeword characteristics of the LDPC
codeword bits and reliability of the bits of the modulation symbol, and is transmitted to the receiver side.
Accordingly, the receiver side can achieve high receiving performance and decoding performance.
Hereinafter, a method for determining n(j), which is a parameter used for group interleaving, according to various exemplary embodiments, will be explained.
According to an exemplary embodiment, when the length of the LDPC codeword is 64800, the size of the bit group is determined to be 360 and thus 180 bit groups exist. In addition, there may be 180! possible interleaving patterns (Herein, factorial means A!=Ax(A-1) x ...x2x1) regarding an integer A.
In this case, since a reliability level between the bits constituting a modulation symbol may be the same according to a modulationorder, many number of interleaving patterns may be regarded as the same interleaving operation when theoretical performance is considered.
For example, when an MSB bit of the X-axis (or rear part-axis) and an MSB bit the Y-axis(or imaginary part-axis) of a certain modulation symbol have the same theoretical reliability, the same theoretical performance can be achieved regardless of the way how specific bits are interleaved to be mapped onto the two MSB bits.
However, such a theoretical prediction may become incorrect as a real channel environment is established. For example, in the case of the QPSK modulation method, two bits of a symbol in a part of a symmetric channel like an additive white Gaussian noise (AWGN) channel theoretically have the same reliability. Therefore, there should be no difference in the performance theoretically when any interleaving method is used. However, in a real channel environment, the performance may be different depending on the interleaving method. In the case of a well-known Rayleigh channel which is not a real channel, the performance of QPSK greatly depends on the interleaving method and thus the performance can be predicted somewhat only by the reliability between bits of a symbol according to a modulation method. However, there should be a limit to predicting the performance.
In addition, since code performance by interleaving may be greatly changed according to a channel which evaluates performance, channels should be always considered to drive an interleaving pattern. For example, a good interleaving pattern in the AWGN
channel may be not good in the Rayleigh channel. If a channel environment where a given system is used is closer to the Rayleigh channel, an interleaving pattern which is better in the Rayleigh channel than in the AWGN channel may be selected.
As such, not only a specific channel environment but also various channel environments considered in a system should be considered in order to derive a good interleaving pattern. In addition, since there is a limit to predicting real performance only by theoretical performance prediction, the performance should be evaluated by directly conducting computation experiments and then the interleaving pattern should be finally determined.
However, since there are so many number of possible interleaving patterns to be applied (for example, 180!), reducing the number of interleaving patterns used to predict and test performance is an important factor in designing a high performance interleaver.
Therefore, the interleaver is designed through the following steps according to an exemplary embodiment.
1) Channels C1, C2, ... Ck to be considered by a system are determined.
2) A certain interleaver pattern is generated.

3) A theoretical performance value is predicted by applying the interleaver generated in step 2) to each of the channels determined in step 1). There are various methods for predicting a theoretical performance value, but a well-known noise threshold determining method like density evolution analysis is used according to an exemplary embodiment. The noise threshold recited herein refers to a value that can be expressed by a minimum necessary signal-to-noise ratio (SNR) capable of error-free transmission on the assumption that a cycle-free characteristic is satisfied when the length of a code is infinite and the code is expressed by the Tanner graph. The density evolution analysis may be implemented in various ways, but is not the subject matter of the inventive concept and thus a detailed description thereof is omitted.
4) When noise thresholds for the channels are expressed as THIN, TH2[i], THk[i] for the i-th generated interleaver, a final determination threshold value may be defined as follows:
TH[i]=WixTHi [i]+W2xTH2N+ +WkxTHk[i], where Wi +W2+ +Wk=1,Wi,W2, = = . , Wk>0 Here, W19 W25 = = = Wk are adjusted according to importance of the channels.
That is, W1 W2, ===) Wk are adjusted to a larger value in a more important channel and W1, W2, = = Wk are adjusted to a smaller value in a less important channel (for example, if the weight values of AWGN and Rayleigh channels are W1 and W2, respectively, WI may be set to 0.25 and W2 may be set to 0.75 when one of the channels is determined to be more important.).
5) B number of interleaver patterns are selected in an ascending order of TH[i] values from among the tested interleaver patterns and are directly tested by conducting performance computation experiments. An PER level for the test is determined as 10^ ¨3 (for example, B=100).
6) D number of best interleaver patterns are selected from among the B number of interleaver patterns tested in step 5) (for example, D=5).
In general, an interleaver pattern which has a great SNR gain in the area of FER=10^ ¨3 may be selected as a good performance interleaver in step of 5). However, according to an exemplary embodiment, as shown in FIG. 16, performance of FER required in the system based on the result of real computation experiments for the area of FER=10A ¨3 may be predicted through extrapolation, and then an interleaver pattern having good performance in comparison with the expected performance in the FER required in the system may be determined as a good interleaver pattern. According to an exemplary embodiment, the extrapolation based on a linear function may be applied. However, various extrapolation methods may be applied. FIG. 16 illustrates an example of performance extrapolation predicted by the result of computation experiments.
7) The D number of interleaver patterns selected in step 6) are tested by conducting performance computation experiments in each channel. Herein, the FER level for testing is selected as FER required in the system (for example, FER=10" ¨6 ) 8) When an error floor is not observed after the computation experiments, an interleaving pattern having the greatest SNR gain is determined as a final interleaving pattern.
FIG. 17 is a view schematically showing a process of determining B number of interleaver patterns in the steps 2), 3), 4), and 5) of the above-described method for determining the interleaving pattern in the case of AWGN and Rayleigh channels for example.
Referring to FIG. 17, necessary variables i, j, and etc. are initialized in operation S1701, and a noise threshold for the AWGN channel TH1[i] and a noise threshold for the Rayleigh channel TH2[i] are calculated in operation S1702. Then, a final determination noise threshold TH[i]
defined in step 4) is calculated in operation S1703, and is compared with a previously calculated final determination noise threshold TH[i-1] in operation S1704. When the final determination noise threshold TH[i] is smaller than the previously calculated final determination noise threshold TH[i-1], TH_S[i] is replaced with the TH[i] and is sotred in operation S1706. Next, i, j values increase by 1 in operation S1707 and this process is repeated until the i value exceeds A
which is pre-defined in operation S1708. In this case, A is the total number of interleaver patterns to be tested in steps 2), 3), 4), and 5) and A is typically determined to be greater than or equal to 10000. When all operations described above are completed, interleaver patterns corresponding to TH_S[0], TH_S[1], TH_S[B-1] which are stored in a descending order of final noise thresholds values in operation S1709.
The transmitting apparatus 100 may transmit the signal mapped onto the constellation to a receiving apparatus (for example, 1200 of FIG. 18). For example, the transmitting apparatus 100 may map the signal mapped onto the constellation onto an Orthogonal Frequency Division Multiplexing (OFDM) frame using OFDM, and may transmit the signal to the receiving apparatus 1200 through an allocated channel.
FIG. 18 is a block diagram to illustrate a configuration of a receiving apparatus according to an exemplary embodiment. Referring to FIG. 18, the receiving apparatus 1200 includes a demodulator 1210, a multiplexer 1220, a deinterleaver 1230 and a decoder 1240.
The demodulator 1210 receives and demodulates a signal transmitted from the transmitting apparatus 100. Specifically, the demodulator 1210 generates a value corresponding to an LDPC
codeword by demodulating the received signal, and outputs the value to the multiplexer 1220. In this case, the demodulator 1210 may use a demodulation method corresponding to a modulation method used in the transmitting apparatus 100. To do so, the transmitting apparatus 100 may transmit information regarding the modulation method to the receiving apparatus 1200, or the transmitting apparatus 100 may perform modulation using a pre-defined modulation method between the transmitting apparatus 100 and the receiving apparatus 1200.
The value corresponding to the LDPC codeword may be expressed as a channel value for the received signal. There are various methods for determining the channel value, and for example, a method for determining a Log Likelihood Ratio (LLR) value may be the method for determining the channel value.
The LLR value is a log value for a ratio of the probability that a bit transmitted from the transmitting apparatus 100 is 0 and the probability that the bit is 1. In addition, the LLR value may be a bit value which is determined by a hard decision, or may be a representative value which is determined according to a section to which the probability that the bit transmitted from the transmitting apparatus 100 is 0 or 1 belongs.
The multiplexer 1220 multiplexes the output value of the demodulator 1210 and outputs the value to the deinterleaver 1230.
Specifically, the multiplexer 1220 is an element corresponding to a demultiplexer (not shown) provided in the transmitting apparatus 100, and performs an operation corresponding to the demultiplexer (not shown). That is, the multiplexer 1220 performs an inverse operation of the operation of the demultiplexer (not shown), and performs cell-to-bit conversion with respect to the output value of the demodulator 1210 and outputs the LLR value in the unit of bit. However, when the demultiplexer (not shown) is omitted from the transmitting apparatus 100, the multiplexer 1220 may be omitted from the receiving apparatus 1200.
The information regarding whether the demultiplexing operation is performed or not may be provided by the transmitting apparatus 100, or may be pre-defined between the transmitting apparatus 100 and the receiving apparatus 1200.
The deinterleaver 1230 deinterleaves the output value of the multiplexer 1220 and outputs the values to the decoder 1240.
Specifically, the deinterleaver 1230 is an element corresponding to the interleaver 120 of the transmitting apparatus 100 and performs an operation corresponding to the interleaver 120. That is, the deinterleaver 1230 deinterleaves the LLR value by performing the interleaving operation of the interleaver 120 inversely.
To do so, the deinterleaver 1230 may include a block deinterleaver 1231, a group twist deinterleaver 1232, a group deinterleaver 1233, and a parity deinterleaver 1234 as shown in FIG.
18.
The block deinterleaver 1231 deinterleaves the output of the multiplexer 1220 and outputs the value to the group twist deinterleaver 1232.
Specifically, the block deinterleaver 1231 is an element corresponding to the block interleaver 124 provided in the transmitting apparatus 100 and performs the interleaving operation of the block interleaver 124 inversely.
That is, the block deinterleaver 1231 deinterleaves by writing the LLR value output from the multiplexer 1220 in each row in the row direction and reading each column of the plurality of rows in which the LLR value is written in the column direction by using at least one row formed of the plurality of columns.
In this case, when the block interleaver 124 interleaves by dividing the column into two parts, the block deinterleaver 1231 may deinterleave by dividing the row into two parts.
In addition, when the block interleaver 124 writes and reads in and from the bit group that does not belong to the first part in the row direction, the block deinterleaver 1231 may deinterleave by writing and reading values corresponding to the group that does not belong to the first part in the row direction.
Hereinafter, the block deinterleaver 1231 will be explained with reference to FIG. 20.
However, this is merely an example and the block deinterleaver 1231 may be implemented in other methods.
An input LLR vi (0<i<Nkipc) is written in a ri row and a ci column of the block deinterleaver [ i 1231. Herein, ci=(i mod NO and r, =
Nc On the other hand, an output LLR qi(0<i<I=I0x No) is read from a ci column and a ri row of the i first part of the block deinterleaver 1231. Herein, c, = ¨ , ri.(i mod Nri).
[
Nrl In addition, an output LLR qi(Nc x Nri<i<Nidpc) is read from a c, column and a ri row of the second part. Herein, c, = [ (i ¨ Ncx NTH, ri=Nri+{(i-Ncx Nri) mode Nr2}.
Nr2 The group twist deinterleaver 1232 deinterleaves the output value of the block deinterleaver 1231 and outputs the value to the group deinterleaver 1233.
Specifically, the group twist deinterleaver 1232 is an element corresponding to the group twist interleaver 123 provided in the transmitting apparatus 100, and may perform the interleaving operation of the group twist interleaver 123 inversely.
That is, the group twist deinterleaver 1232 may rearrange the LLR values of the same bit group by changing the order of the LLR values existing in the same bit group.
When the group twist operation is not performed in the transmitting apparatus 100, the group twist deinterleaver 1232 may be omitted.
The group deinterleaver 1233 (or the group-wise deinterleaver) deinterleaves the output value of the group twist deinterleaver 1232 and outputs the value to the parity deinterleaver 1234.
Specifically, the group deinterleaver 1233 is an element corresponding to the group interleaver 122 provided in the transmitting apparatus 100 and may perform the interleaving operation of the group interleaver 122 inversely.
That is, the group deinterleaver 1233 may rearrange the order of the plurality of bit groups in bit group wise. In this case, the group deinterleaver 1233 may rearrange the order of the plurality of bit groups in bit group wise by applying the interleaving method of Tables 11 to 22 inversely according to a length of the LDPC codeword, a modulation method and a code rate.
The parity deinterleaver 1234 performs parity deinterleaving with respect to the output value of the group deinterleaver 1233 and outputs the value to the decoder 1240.
Specifically, the parity deinterleaver 1234 is an element corresponding to the parity interleaver 121 provided in the transmitting apparatus 100 and may perform the interleaving operation of the parity interleaver 121 inversely. That is, the parity deinterleaver 1234 may deinterleave the LLR values corresponding to the parity bits from among the LLR values output from the group deinterleaver 1233. In this case, the parity deinterleaver 1234 may deinterleave the LLR value corresponding to the parity bits inversely to the parity interleaving method of Equation 18.
However, the parity deinterleaver 1234 may be omitted depending on the decoding method and embodiment of the decoder 1240.
Although the deinterleaver 1230 of FIG. 18 includes three (3) or four (4) elements as shown in FIG. 19, operations of the elements may be performed by a single element.
For example, when bits each of which belongs to each of bit groups Xa, Xb, X, Xd constitute a single modulation symbol, the deinterleaver 1230 may deinterleave these bits to locations corresponding to their bit groups based on the received single modulation symbol.
For example, when the code rate is 6/15 and the modulation method is 16-QAM, the group deinterleaver 1233 may perform deinterleaving based on table 11.
In this case, bits each of which belongs to each of bit groups X55, X15, X112, X122 may constitute a single modulation symbol. Since one bit in each of the bit groups X55, X15, X112, X122 constitutes a single modulation symbol, the deinterleaver 1230 may map bits onto decoding initial values corresponding to the bit groups X55, X15, X112, X122 based on the received single modulation symbol.
The decoder 1240 may perform LDPC decoding by using the output value of the deinterleaver 1230. To achieve this, the decoder 1240 may include an LDPC
decoder (not shown) to perform the LDPC decoding.
Specifically, the decoder 1240 is an element corresponding to the encoder 110 of the transmitting apparatus 100 and may correct an error by performing the LDPC
decoding by using the LLR value output from the deinterleaver 1230.
For example, the decoder 1240 may perform the LDPC decoding in an iterative decoding method based on a sum-product algorithm. The sum-product algorithm is one example of a message passing algorithm, and the message passing algorithm refers to an algorithm which exchanges messages (e.g., LLR value) through an edge on a bipartite graph, calculates an output message from messages input to variable nodes or check nodes, and updates.
The decoder 1240 may use a parity check matrix when performing the LDPC
decoding. In this case, the parity check matrix used in the decoding may have the same configuration as that of the parity check matrix used in the encoding of the encoder 110, and this has been described above with reference to FIGs. 2 to 4.
In addition, information on the parity check matrix and information on the code rate, etc.

which are used in the LDPC decoding may be pre-stored in the receiving apparatus 1200 or may be provided by the transmitting apparatus 100.
FIG. 21 is a flowchart to illustrate an interleaving method of a transmitting apparatus according to an exemplary embodiment.
First, an LDPC codeword is generated by LDPC encoding based on a parity check matrix (S1410), and the LDPC codeword is interleaved (S1420).
Then, the interleaved LDPC codeword is mapped onto a modulation symbol (S1430). In this case, a bit included in a predetermined bit group from among a plurality of bit groups constituting the LDPC codeword may be mapped onto a predetermined bit in the modulation symbol.
Each of the plurality of bit groups may be formed of M number of bits, and M
may be a common divisor of Nidpc and Kidpc and may be determined to satisfy Qldpc=(Nldpc-Kldpc)/M.
Herein, Qapc is a cyclic shift parameter value regarding columns in a column group of an information word submatrix of the parity check matrix, Nidpc is a length of the LDPC codeword, and Kid is a length of information word bits of the LDPC codeword.
Operation S1420 may include interleaving parity bits of the LDPC codeword, dividing the parity-interleaved LDPC codeword by the plurality of bit groups and rearranging the order of the plurality of bit groups in bit group wise, and interleaving the plurality of bit groups the order of which is rearranged.
The order of the plurality of bit groups may be rearranged in bit group wise based on the above-described Equation 21 presented above.
As described above, t(j) in Equation 21 may be determined based on at least one of a length of the LDPC codeword, a modulation method, and a code rate.
For example, when the LDPC codeword has a length of 64800, the modulation method is 16-QAM, and the code rate is 6/15, n(j) may be defined as in table 11.
In addition, when the LDPC codeword has a length of 64800, the modulation method is 16-QAM, and the code rate is 10/15, n(j) may be defined as in table 14.
In addition, when the LDPC codeword has a length of 64800, the modulation method is 16-QAM, and the code rate is 12/15, z(j) may be defined as in table 15.
In addition, when the LDPC codeword has a length of 64800, the modulation method is 64-QAM, and the code rate is 6/15, n(j) may be defined as in table 17.

In addition, when the LDPC codeword has a length of 64800, the modulation method is 64-QAM, and the code rate is 8/15, n(j) may be defined as in table 18.
In addition, when the LDPC codeword has a length of 64800, the modulation method is 64-QAM, and the code rate is 12/15, m(j) may be defined as in table 21.
The interleaving the plurality of bit groups may include: writing the plurality of bit groups in each of a plurality of columns in bit group wise in a column direction, and reading each row of the plurality of columns in which the plurality of bit groups are written in bit group wise in a row direction.
In addition, the interleaving the plurality of bit groups may include:
serially write, in the plurality of columns, at least some bit group which is writable in the plurality of columns in bit group wise from among the plurality of bit groups, and then dividing and writing the other bit groups in an area which remains after the at least some bit group is written in the plurality of columns in bit group wise.
A non-transitory computer readable medium, which stores a program for performing the interleaving methods according to various exemplary embodiments in sequence, may be provided.
The non-transitory computer readable medium refers to a medium that stores data semi-permanently rather than storing data for a very short time, such as a register, a cache, and a memory, and is readable by an apparatus. Specifically, the above-described various applications or programs may be stored in a non-transitory computer readable medium such as a compact disc (CD), a digital versatile disk (DVD), a hard disk, a Blu-ray disk, a universal serial bus (USB), a memory card, and a read only memory (ROM), and may be provided.
At least one of the components, elements or units represented by a block as illustrated in FIGs. 1, 5, 15, 18 and 19 may be embodied as various numbers of hardware, software and/or firmware structures that execute respective functions described above, according to an exemplary embodiment. For example, at least one of these components, elements or units may use a direct circuit structure, such as a memory, processing, logic, a look-up table, etc.
that may execute the respective functions through controls of one or more microprocessors or other control apparatuses. Also, at least one of these components, elements or units may be specifically embodied by a module, a program, or a part of code, which contains one or more executable instructions for performing specified logic functions. Also, at least one of these components, elements or units may further include a processor such as a central processing unit (CPU) that performs the respective functions, a microprocessor, or the like. Further, although a bus is not illustrated in the above block diagrams, communication between the components, elements or units may be performed through the bus. Functional aspects of the above exemplary embodiments may be implemented in algorithms that execute on one or more processors.
Furthermore, the components, elements or units represented by a block or processing steps may employ any number of related art techniques for electronics configuration, signal processing and/or control, data processing and the like.
The foregoing exemplary embodiments and advantages are merely exemplary and are not to be construed as limiting the present inventive concept. The exemplary embodiments can be readily applied to other types of apparatuses. Also, the description of the exemplary embodiments is intended to be illustrative, and not to limit the scope of the inventive concept, and many alternatives, modifications, and variations will be apparent to those skilled in the art.

Claims

[CLAIMS]

1. A transmitting apparatus comprising:
an encoder configured to encode input bits to generate parity bits based on a low density parity check (LDPC) code according to a code rate of 6/15 and a code length of 64800;
an interleaver configured to interleave the parity bits, split a codeword into a plurality of bit groups, and interleave the plurality of bit groups to provide an interleaved codeword, wherein the codeword comprising the input bits and the interleaved parity bits; and a mapper configured to map bits of the interleaved codeword onto constellation points for 16-quadrature amplitude modulation(QAM), wherein the plurality of bit groups are interleaved based on a following equation:
Y j = X .pi.(j) for (0<=j< N group) where X j is a j th bit group among the plurality of bit groups, Y j is a j th bit group among the interleaved plurality of bit groups, N group is a total number of the plurality of bit groups, and .pi.(j) denotes a permutation order for the interleaving of the plurality of bit groups, and wherein the .pi.(j) is defined as follows:

2. The transmitting apparatus of claim 1, wherein each of the plurality of bit groups comprises 360 bits.