ES2437144T3 - Apparatus and method for channel coding and decoding in a communication system using low density parity check codes - Google Patents

Abstract

A method of decoding a channel in a communication system using a low density parity check code (LDPC), comprising the steps of: extracting a parity checking matrix from the LDPC code; and perform LDPC decoding using the extracted parity check matrix; in which the parity check matrix has N1 columns, where N1 is 16200 columns, the parity check matrix has an information part and a parity part, in which the information part has K1 columns, where K1 is 9720, and the parity part has a double diagonal form and (N1-K1) columns, where (N1-K1) is 6480, in which the information part comprises a series of groups of columns, having each group of columns M1 columns, where M1 is 360, and the number of column groups is K1 / M1, where K1 / M1 is 27; in which a code rate is 3/5, the position sequences of '1's in the 0 th column in the ith column group, i> = 0, ..., 26, indicated by ** Formula ** are: ** Table **

Description

Apparatus and method for channel coding and decoding in a communication system using low density parity check codes.

BACKGROUND OF THE INVENTION

one.

Field of the Invention

The present invention relates in general to a communication system using low density parity check codes (LDPC), and more particularly, but not exclusively, to an apparatus and a coding method / channel decoding to generate LDPC codes of a particular type.

2.

 Description of the related technique

In wireless communication systems, link performance decreases significantly due to various channel noises, fading phenomenon and inter-symbol interference (ISI, Inter-Symbol Interference). Therefore, to achieve high-speed digital communication systems that require high data throughput and reliability, such as next-generation mobile communication, digital broadcasting and portable internet, it is necessary to develop a technology to overcome noise, fading and ISI . Recently, a thorough study has been conducted on the use of an error correction code to increase the reliability of communication by efficiently recovering distorted information.

The LDPC code, first introduced by Gallager in the 1960s, has been underused due to its complex implementation, which could not be solved by prior technology. However, the turbo code, which was discovered by Berrou, Glavieux and Thitimajshima of 1993, presents a behavior that approximates the limit of the Shannon canal. Therefore, research on iterative decoding and graphical channel coding has been carried out, along with analysis on the performance and characteristics of the turbo code. Due to these investigations, the LDPC code has been re-studied at the end of the 1990s, demonstrating that the LDPC code has a behavior close to the Shannon channel limit, if it is subjected to decoding by means of iterative decoding application based on a sum-product algorithm on a Tanner graph (a special case of a factor graph) corresponding to the LDPC code.

The LDPC code is usually represented using a graph representation technique, and many features can be analyzed using methods based on graph theory, algebra and probability theory. In general, a channel code graph model is useful for code description. By mapping information in coded bits, to vertices in the graph, and mapping relationships between the bits, to edges in the graph, it is possible to consider a communication network in which the vertices exchange predetermined messages through the edges. This makes it possible to obtain a natural decoding algorithm. For example, a decoding algorithm obtained from a crosslinked graph ("trellis"), which can be considered a kind of graph, can include the well-known Viterbi algorithm and an algorithm of Bahl, Cocke, Jelinek and Raviv (BCJR ).

The LDPC code is generally defined as a parity check matrix, and can be expressed using a bipartite graph, which is called a Tanner graph. In the bipartite graph the vertices that constitute the graph are divided into two different types, and the LDPC code is represented by the bipartite graph composed of vertices, of which some are called variable nodes and the other check nodes. Variable nodes are mapped one by one to the encoded bits.

Referring to Figures 1 and 2, a description of a graph representation method for the LDPC code will be made.

Figure 1 shows an example of an H1 parity check matrix of the LDPC code consisting of 4 rows and 8 columns. Referring to Figure 1, since the number of columns is 8, an LDPC code generates a code word of length 8, and the columns are mapped to 8 coded bits.

Figure 2 is a diagram showing a Tanner graph corresponding to H1 of Figure 1.

Referring to Figure 2, the Tanner graph of the LDPC code consists of 8 variable nodes x1 (202), x2 (204), x3 (206), x4 (208), x5 (210), x6 (212), x7 (214) and x8 (216), and 4 check nodes 218, 220, 222 and 224. An i-th column and a j-estimate row in the parity check matrix H1 of the LDPC code are mapped to a variable node xi already a jth verification node, respectively. In addition, a value of 1, that is, a nonzero value, at the position where an i-th column and a j-th row intersect in the matrix of

parity check H1 of the LDPC code indicates that there is an edge between the variable node xi and the jth check node in the Tanner graph shown in Figure 2.

In the Tanner graph of the LDPC code, the degree of the variable node and the check node is defined as the number of edges contained in each respective node, and the degree is equal to the number of nonzero entries in a column or row corresponding to the associated node in the parity check matrix of the LDPC code. For example, in Figure 2, the degrees of the variable nodes x1 (202), x2 (204), x3 (206), x4 (208), x5 (210), x6 (212), x7 (214) and x8 (216) are 4, 3, 3, 3, 2, 2, 2 and 2, respectively, and the degrees of the check nodes 218, 220, 222 and 224 are 6, 5, 5 and 5, respectively. In addition, the numbers of nonzero entries in the columns of the parity check matrix H1 of Figure 1, which correspond to the variable nodes of Figure 2, are equal to their grades 4, 3, 3, 3, 2 , 2, 2 and 2. The numbers of nonzero entries in the rows of the parity check matrix H1 of Figure 1, which correspond to the check nodes of Figure 2, are equal to their grades 6, 5 , 5 and 5.

To express the distribution of degrees for the nodes of the LDPC code, the ratio of the number of variable nodes of degree-i to the total number of variable nodes is defined as fi, and the ratio of the number of verification nodes of degree j to the Total number of check nodes is defined as gj. For example, for the LDPC code corresponding to Figures 1 and 2, f2 = 4/8, f3 = 3/8, f4 = 1/8, and fi = 0 for in, 3, 4; and g5 = 3/4, g6 = 1/4, and gj = 0 for jn5, 6. When the length of the LDPC code, that is, the number of columns, is defined as N, and the number of rows is defined as N / 2, the density of nonzero inputs in the entire parity check matrix that has the above degree distribution is calculated according to equation (1).

In equation (1), when N increases, the density of '1's in the parity check matrix decreases. In general, in relation to the LDPC code, since the length N of the code is inversely proportional to the density of nonzero entries, a LDPC code with large N has a very low density of nonzero inputs. The expression 'low density' for the LDPC code originates from the relationship mentioned above.

Next, referring to Figure 3, a description of characteristics of a parity check matrix of a structured LDPC code to be applied in the present invention will be made. Figure 3 schematically shows an LDPC code adopted in the standard second generation digital video broadcast satellite signal broadcasting technology (DVB-S2, Digital Video Broadcasting-Satellite transmission 2nd generation), which is one of the European digital broadcasting standards .

In Figure 3, N1 indicates a length of an LDPC code word, K1 indicates a length of the information word, and (N1-K1) provides a parity length. In addition, the integers M1 and q are determined so that they satisfy q = (N1-K1) / M1. Preferably, K1 / M1 should also be an integer.

Referring to Fig. 3, a structure of a parity part, that is, column K1-th through column (N1-1) -th, in the parity check matrix, has a double diagonal shape. Therefore, in relation to the distribution of grade over the columns corresponding to the parity part, all columns have grade '2', except for the last column, which has grade '1'.

In the parity check matrix, a structure of a piece of information, that is, column 0-th through column (K1-1) -th, is made using the following rules.

Rule 1: A total of K1 / M1 groups of columns are generated by grouping K1 columns corresponding to the information word in the parity check matrix, into multiple groups, each composed of M1 columns. Follow a method to form columns belonging to each group of columns in the following rule 2.

Rule 2: the positions of '1's in each 0-th column in groups of ith columns are determined first (where i = 1, ..., K1 / M1). When a grade of a 0th column in each group of ith columns is

indicates by Say, if it is assumed that the positions of the rows with 1 are the positions

 of the rows with 1 are defined according to equation (2), in a jth column (where j = 1, 2, ..., M1-1) in a group of ith columns.

According to the previous rules, it can be seen that the degrees of the columns belonging to a group of i-th columns (where i = 1, ..., K1 / M1) are all equal to Di. For a better understanding of the structure of a DVB-S2 LDPC code that stores information about the parity check matrix according to the above rules, the following detailed example will be described.

As a detailed example, for N1 = 30, K1 = 15, M1 = 5 and q = 3, three sequences can be expressed as follows for the information about the positions of the rows with 1 for the 0-th columns in 3 groups of columns. In the present description, these sequences are conveniently referred to as "weighting position sequences-1".

In relation to the weighting position sequence-1 for the 0 th columns in each group of columns, only the corresponding position sequences can be expressed as follows for each group of columns. For example:

0 1 2

0 11 13

0 10 14.

In other words, the sequence of weighting position-1 in the i-th line sequentially represents the information of the positions of the rows with 1 in the group of i-th columns.

It is possible to generate an LDPC code that has the same concept as that of a DVB-S2 LDPC code in Figure 4, by forming a parity check matrix using the information corresponding to the example

20 detailed, and rule 1 and rule 2.

It is known that the DVB-S2 LDPC code designed in accordance with rule 1 and rule 2 can be efficiently encoded using the structural form. The respective steps in an LDPC coding realization process using the parity check matrix based on DVB-S2 will now be described by way of example.

25 In the following description, as a detailed example, a DVB-S2 LDPC code with N1 = 16200, K1 = 10800, M1 = 360 and q = 15 is subjected to a coding process. For convenience, the information bits having a length K1 are represented as (i0, i1, ..., iK1-1), and the parity bits having a length of (N1-K1) are expressed as (p0, p1, ..., pN1-K1-1).

Stage 1: An LDPC encoder initializes parity bits, as follows:

Stage 2: The LDPC encoder reads information about a row where there is a 1 in a group of columns, from a sequence of weighting position-1 0 th of the stored sequences that indicate the parity check matrix.

0 2084 1613 1548 1286 1460 3196 4297 2481 3369 3451 4620 2622 The LDPC encoder updates the specific parity bits px according to equation (3) using the information read and the first bit of information i0. In the present description, x indicates a value of

 for k = 1,

2, ..., 13.

In equation (3), px = px E i0 can also be expressed as px <px E i0, and E indicates binary sum.

Stage 3: The LDPC encoder first finds a value from equation (4) for the next 359 bits of information im (where m = 1, 2, ..., 359) after i0.

concept that equation (2).

Next, the LDPC encoder performs an operation similar to equation (3) using the value found in equation (4). That is, the LDPC encoder updates p {x + (m mod M1) × q} mod (N1-K1) for im. For example, for m = 1, that is, for i1, the LDPC encoder updates to the parity bits p (x + q) mod (N1-K1) as defined in equation (5).

It should be noted that q = 15 in equation (5). The LDPC encoder performs the above process for m = 1, 2, ..., 359 in the same way as shown above.

 for a 361-th bit of information i360, and updates a particular px, where x

 The LDPC encoder updates p {x + (m mod M1) × q} mod (N1-K1), m = 361, 362, ..., 719 by similarly applying equation (4) to the next 359 bits of information i361, i362, ..., i719 after i360.

Stage 5: the LDPC encoder repeats stages 2, 3 and 4 for all groups each having 360 bits of information.

Step 6: The LDPC encoder finally determines parity bits using equation (6).

The parity bits pi of equation (6) are parity bits that have received LDPC encoding.

As described above, in DVB-S2, the LDPC encoder performs LDPC encoding by the process of steps 1 to 6.

It is well known that the behavior of the LDPC code is closely related to the cycle characteristics of the Tanner graph. In particular, it is known by experiments that performance degradation can occur when the number of short length cycles is greater in the Tanner graph. Therefore, the characteristics of the cycle in the Tanner graph must be taken into account to design LDPC codes with high performance.

However, no method has been proposed that designs DVB-S2 LDPC codes that have good cycle characteristics. For the DVB-S2 LDPC code, an error ground phenomenon is observed, at a certain signal-to-noise ratio (SNR), when the optimization of the Tanner graph cycle characteristics is not considered. For these reasons, there is a need for a method capable of effectively improving the cycle characteristics in the design of LDPC codes that have the DVB-S2 structure.

SUMMARY OF THE INVENTION

The present invention has been made to solve at least the above problems and / or disadvantages and to provide at least the advantages described below. Accordingly, an aspect related to the present invention but not part of it provides an apparatus and a channel coding / decoding method for designing a parity check matrix of a quasi-cyclic LDPC code designed based on a matrix of circulating permutation to design a DVB-S2 LDPC code in a communication system that uses LDPC codes.

Another aspect related to the present invention but not part of it, discloses an apparatus and a channel coding / decoding method to design a parity check matrix of the same LDPC code as the DVB-S2 LDPC code that have a good Tanner graph characteristic in a communication system that uses LDPC codes.

In accordance with an aspect related to the present invention but not part of it, a method for generating a parity check matrix of a low density parity check code (LDPC) is disclosed. Parameters are determined to design the LDPC code. A first parity check matrix of a quasi-cyclic LDPC code is formed according to the determined parameters. A second parity check matrix is created by removing the predetermined part of a parity part in the first parity check matrix. A third parity check matrix is created by rearranging the second parity check matrix.

In accordance with one aspect of the present invention, a method for encoding a channel in a communication system using a low density parity check code (LDPC) is disclosed. A stored parity check matrix is read. A received signal is encoded in LDPC using the stored parity check matrix. The parity check matrix is divided into an information word and a parity. When the code rate is 3/5 and the length of the code word is 16200, the parity check matrix is formed as defined in the following table:

71 1478 1901 2240 2649 2725 3592 3708 3965 4080 5733 6198 393 1384 1435 1878 2773 3182 3586 5465 6091 6110 6114 6327 160 1149 1281 1526 1566 2129 2929 3095 3223 4250 4276 4612 289 1446 1602 2421 3559 3796 5590 5750 5763 6168 6271

(continuation)

947 1227 2008 2020 2266 3365 3588 3867 4172 4250 4865 6290 3324 3704 4447 1206 2565 3089 529 4027 5891 141 1187 3206 1990 2972 5120 752 796 5976 1129 2377 4030 6077 6108 6231 61 1053 1781 2820 4109 5307 2088 5834 5988 3725 3945 4010 1081 2781 3389 659 2221 4822 3033 6060 6160 756 1489 2350 3350 3624 5470 357 1825 5242 585 3372 6062 561 1417 2348 971 3719 5567 1005 1675 2062

In accordance with another embodiment of the present invention, a method for decoding a channel in a communication system using a low density parity check code (LDPC) is disclosed. A parity check matrix is extracted from the LDPC code. LDPC decoding is performed using the extracted parity check matrix. The extracted parity check matrix is divided into a parity and an information word. When the code rate is 3/5 and the length of the code word is 16200, the parity check matrix is formed as defined in the following table:

71 1478 1901 2240 2649 2725 3592 3708 3965 4080 5733 6198 393 1384 1435 1878 2773 3182 3586 5465 6091 6110 6114 6327 160 1149 1281 1526 1566 2129 2929 3095 3223 4250 4276 4612 289 1446 1602 2421 3559 3796 5590 5750 5763 6168 12277 2008 2020 2266 3365 3588 3867 4172 4250 4865 6290 3324 3704 4447 1206 2565 3089 529 4027 5891 141 1187 3206 1990 2972 5120 752 796 5976 1129 2377 4030 6077 6108 6231 61 1053 1781 2820 4109 5307 2088 5834 5988 3725 3945 4010 1081 2780 3389 659 2221 4822 3033 6060 6160 756 1489 2350 3350 3624 5470 357 1825 5242 585 3372 6062 561 1417 2348 971 3719 5567 1005 1675 2062

In accordance with a further aspect of the present invention, an apparatus for encoding a channel in a communication system using a low density parity check code (LDPC) is disclosed. An 8

LDPC code parity check matrix extractor reads a stored parity check matrix. An LDPC encoder encodes a received signal using the stored parity check matrix in LDPC. The parity check matrix is divided into a parity and an information word. When the code rate is 3/5 and the length of the code word is 16200, the parity check matrix is formed as defined in the following table:

71 1478 1901 2240 2649 2725 3592 3708 3965 4080 5733 6198 393 1384 1435 1878 2773 3182 3586 5465 6091 6110 6114 6327 160 1149 1281 1526 1566 2129 2929 3095 3223 4250 4276 4612 289 1446 1602 2421 3559 3796 5590 5750 5763 6168 12277 2008 2020 2266 3365 3588 3867 4172 4250 4865 6290 3324 3704 4447 1206 2565 3089 529 4027 5891 141 1187 3206 1990 2972 5120 752 796 5976 1129 2377 4030 6077 6108 6231 61 1053 1781 2820 4109 5307 2088 5834 5988 3725 3945 4010 1081 2780 3389 659 2221 4822 3033 6060 6160 756 1489 2350 3350 3624 5470 357 1825 5242 585 3372 6062 561 1417 2348 971 3719 5567 1005 1675 2062

In accordance with another aspect of the present invention, an apparatus for decoding a channel in a communication system using a low density parity check code (LDPC) is disclosed. An LDPC code parity check matrix extractor reads a stored parity check matrix. An LDPC decoder performs LDPC decoding using the parity check matrix read. The parity check matrix read is divided into a parity and an information word. When the code rate is 3/5 and the length of the code word is 16200, the parity check matrix is formed as defined in the following table:

71 1478 1901 2240 2649 2725 3592 3708 3965 4080 5733 6198 393 1384 1435 1878 2773 3182 3586 5465 6091 6110 6114 6327 160 1149 1281 1526 1566 2129 2929 3095 3223 4250 4276 4612 289 1446 1602 2421 3559 3796 5590 5750 5763 6168 12271 2008 2020 2266 3365 3588 3867 4172 4250 4865 6290 3324 3704 4447 1206 2565 3089 529 4027 5891 141 1187 3206 1990 2972 5120 752 796 5976 1129 2377 4030 6077 6108 6231 61 1053 1781 2820 4109 5307 2088 5834 5988 3725 3945 4010 1081 2780 3389 659 2221 4822 3033 6060 6160 756 1489 2350 3350 3624 5470 357 1825 5242 585 3372 6062 561 1417 2348

(continuation)

971 3719 5567 1005 1675 2062

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other aspects, features and advantages of the present invention will become more apparent from the following detailed description, when taken together with the accompanying drawings, in which:

Figure 1 is a diagram showing a parity check matrix of an LDPC code of length 8;

Figure 2 is a diagram showing a Tanner graph of a parity check matrix of an LDPC code of length 8;

Figure 3 is a diagram showing a schematic structure of a DVB-S2 LDPC code;

Figure 4 is a diagram showing a parity check matrix of a DVB-S2 LDPC code;

Figure 5 is a diagram showing a parity check matrix generated by rearranging columns and rows in the parity check matrix of the DVB-S2 LDPC code of Figure 4, according to predetermined rules, according to an embodiment that does not form part of the present invention;

Figure 6 is a diagram showing a parity check matrix of a quasi-cyclic LDPC code needed to design a DVB-S2 LDPC code, in accordance with an embodiment that is not part of the present invention;

Figure 7 is a diagram showing the result obtained by transforming the parity check matrix of the quasi-cyclic LDPC code necessary to design a DVB-S2 LDPC code, in accordance with an embodiment that is not part of the present invention;

Figure 8 is a flow chart showing a design process of a DVB-S2 LDPC code, in accordance with an embodiment that is not part of the present invention;

Figure 9 is a diagram showing a computer simulation result of the DVB-S2 LDPC code, in accordance with an embodiment of the present invention;

Figure 10 is a block diagram showing a structure of a transceiver in a communication system using the redesigned DVB-S2 LDPC code, in accordance with an embodiment of the present invention;

Figure 11 is a block diagram showing a structure of a transmission apparatus using an LDPC code, in accordance with an embodiment of the present invention;

Figure 12 is a block diagram showing a structure of a receiving apparatus using an LDPC code, in accordance with an embodiment of the present invention; Y

Fig. 13 is a flow chart showing a receiving operation of a receiving apparatus using an LDPC code, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the present invention are described in detail with reference to the accompanying drawings. The same or similar components are indicated by the same or similar reference numerals even if they are shown in different drawings. Detailed descriptions of constructions or processes known in the art may have been omitted to avoid obscuring the subject of the present invention.

The present invention discloses a method for designing a DVB-S2 LDPC code that has a good Tanner graph characteristic. In addition, the present invention discloses a method for generating a word.

of LDPC code using a parity check matrix of the previously designed LDPC code, and an apparatus for the same.

Next, structural characteristics of a DVB-S2 LDPC code using a parity check matrix of a DVB-S2 LDPC code shown in Figure 4 are described. For parity check matrix shown in Figure 4, N1 = 30, K1 = 15, M1 = 5 and q = 3, and the weighting position sequences-1 of the rows for the 0-th columns in the three groups of columns are as follows:

0 11 13

In this case, a sequence of weighting position-1 in the i-th line sequentially represents the information about the positions of the rows with 1 in the group of i-th columns.

The parity check matrix of Figure 4 is reconstructed according to the following rules. Figure 4 is a diagram showing a parity check matrix of a DVB-S2 LDPC code.

Rule 3: 0-th rows up to (N1-K1-1) -th are reordered so that one row (q · i + j) -th is placed in a row (M1 · j + i) -th 0: i: M1 and 0: j <q.

Rule 4: keeping columns 0-th to (K1-1) -th, intact, columns K1-th to (N1-1) th are rearranged so that one column (K1 + q · i + j) -th is located in a column (K1 + M1 · j + i) -th.

A parity check matrix with a shape shown in figure 5 is obtained by reconstructing the parity check matrix of figure 4, according to rule 3 and rule 4. Figure 5 shows a parity check matrix generated by rearranging columns and rows in the parity check matrix of the DVB-S2 LDPC code of Figure 4, in accordance with predetermined rules, according to an embodiment of the present invention.

If in Figure 5 it is assumed that '1' exists in a column (N1-1) -th in a 0-th row, it can be seen that the parity check matrix of Figure 5 corresponds to a quasi-cyclic LDPC code class consisting of a circulating permutation matrix with a size of M1 × M1, ie 5 x 5. The 'circulating permutation matrix' is defined as a kind of permutation matrix created by circularly moving rows in identity matrices towards the right, one at a time. In addition, the 'quasi-cyclic LDPC code' is defined as a class of LDPC code created by dividing a parity check matrix into several blocks of the same size and mapping circulating permutation matrices or zero matrices, to the blocks.

In summary, it will be understood that a parity check matrix similar to the quasi-cyclic LDPC code can be obtained by reconstructing a parity check matrix of the DVB-S2 LDPC code according to rule 3 and rule 4. Likewise, it is considered that the DVB-S2 LDPC code can be generated from the quasi-cyclic LDPC code by the inverse process of rule 3 and rule 4.

While there are no known research results on the DVB-S2 LDPC code, there are many known design methods for the quasi-cyclic LDPC code. The design methods for the quasi-cyclic LDPC code include well-known methods to optimize cycle characteristics on the Tanner graph.

An embodiment that is not part of the invention proposes a method for designing a DVB-S2 LDPC code using the well known method to improve cycle characteristics on the Tanner graph of the quasi-cyclic LDPC code. However, since the method for improving the cycle characteristics of the quasi-cyclic LDPC code is only indirectly related to the present invention, for greater simplicity a detailed description thereof will be omitted.

A description of a method for designing a DVB-S2 LDPC code using a quasi-cyclic LDPC code is provided below. The DVB-S2 LDPC code has a code word length N1, an information length K1 and a parity length (N1-K1), and q = (N1-K1) / M1.

A parity check matrix of a quasi-cyclic LDPC code is shown in Figure 6. Figure 6 is a diagram showing a parity check matrix of a quasi-cyclic LDPC code needed to design a DVB-S2 LDPC code, in accordance with an embodiment of the present invention. The parity check matrix shown in Figure 6 has (N1-K1) rows and N1 columns, and is divided into blocks

partial M1 × M1. For convenience, if t = K1 // M1, a part of information and a part of parity in the parity check matrix of Figure 6 consist of t blocks of columns and q blocks of columns, respectively, and have a total of q blocks of rows. In this case, N1 / M1 = t + q.

The respective partial blocks that constitute the parity check matrix of Figure 6 correspond to circulating permutation matrices or zero matrices. In this case, the circulating permutation matrix has a size of M1 × M1, and is created based on a circulating permutation matrix P, which is defined as:

In Figure 6, aij is an integer from 0 to M1-1 or a value of �, P0 is defined as an identity matrix I, and P� indicates a zero matrix M1 × M1. Also, the numerals '0' in the parity part indicate zero matrices M1 × M1.

The parity check matrix of Figure 6 is characterized in that the column blocks corresponding to the parity have identity matrices I and a circulating permutation matrix PM1-1, as shown in the drawing. In other words, the column blocks corresponding to parity are fixed in the structure shown in Figure 6. The circulating permutation matrix PM1-1 is defined as:

The quasi-cyclic LDPC code shown in Figure 6 is the part that remains invariant in the process of optimizing the cycles of the quasi-cyclic LDPC code when the structures of the column blocks corresponding to its parity part are fixed. In other words, since the column blocks corresponding to the parity part are fixed in the parity check matrix of Figure 6, the connections between variable nodes corresponding to the parity are determined on the Tanner graph, so that it is only necessary to optimize the connections between variable nodes corresponding to the information part, in order to optimize Tanner graph cycles.

As described above, there are many known methods for optimizing cycle characteristics on the Tanner graph of the quasi-cyclic LDPC code. Since the design method for the quasi-cyclic LDPC code with a Tanner graph with the optimized cycle characteristics is only indirectly related to the present invention, a detailed description thereof will be omitted in the present description.

It is assumed that a degree distribution is determined to show excellent behavior in the state in which the structure of the parity part is fixed in the quasi-cyclic parity check matrix of Figure 6, by the design method for the LDPC code quasi-cyclic The positions of the circulating permutation matrix and zero matrices are determined in the column blocks corresponding to the information part, according to the degree distribution. The cycle characteristics of the Tanner graph are optimized.

The shape of Figure 7 can be realized, for example, by removing '1' from the last column in the first row in the circulating permutation matrix PM1-1 corresponding to the last block of columns (N1 / M1) -th or (t + q) -th in the first block of rows in the parity check matrix of Figure 6. Figure 7 is a diagram showing the result obtained by transforming the parity check matrix of the quasi-cyclic LDPC code needed to design a code DVB-S2 LDPC, according to an embodiment that is not part of the present invention.

It should be noted that in Figure 7 the circulating permutation matrix PM1-1 becomes the following matrix Q.

The following rule 5 and rule 6 are defined to apply the inverse process to rule 3 and rule 4.

Rule 5: keeping columns 0-th to (K1-1) -th, intact, columns K-th to (N1-1) -th are rearranged so that column (K1 + M1 · j + i) -th is placed in a column (K1 + q · i + j) -th, where 0: i <M1 and 0: j <q.

Rule 6: 0-th rows are rearranged to (N1-K1-1) -th, so that a row (M1 · j + i) -th is placed in a row (q · i + j) -th.

The parity check matrix of the LDPC code generated from the quasi-cyclic LDPC code of Figure 6 by the process described above applying rule 5 and rule 6, becomes the parity check matrix in the form of the DVB code -S2 LDPC shown in Figure 3, for example. The method described above to design a DVB-S2 parity check matrix, in which its code word, and its information and parity lengths are N1, K1 and (N1-K1), respectively, and q = (N1 -K1) / M1, can be summarized in the following process.

DVB-S2 LDPC code design process

Figure 8 is a flow chart showing a design process of a DVB-S2 LDPC code, in accordance with an embodiment that is not part of the present invention.

Referring to Figure 8, in step 801, parameters necessary to design a desired DVB-S2 LDPC code are determined. In the present description, it is assumed that the parameters such as a code word length and an information length as well as the valid degree distribution, have been determined prior to the design of the DVB-S2 LDPC code.

Next, in step 803, a parity checking matrix of a quasi-cyclic LDPC code consisting of M1 × M1 circulating permutation matrices and zero matrices as shown in Figure 6, is formed according to the parameters defined in the stage 801. In Figure 6, the column blocks corresponding to a parity part are always fixed to a specific shape.

In step 805, circulating permutation matrices are determined, from blocks of columns corresponding to an information part of Figure 6, by applying an algorithm to improve cycle characteristics of a Tanner graph of the quasi-cyclic LDPC code. In the present description any known algorithm can be used to improve cycle characteristics.

In step 807, a parity check matrix shown in Figure 7 is obtained, for example, by removing '1' from the last column in the first row in the parity check matrix of Figure 6, which has been determined in step 805.

In step 809, columns and rows are rearranged in the parity check matrix of Figure 7 by applying rule 5 and rule 6 to the parity check matrix of Figure 7. The parity check matrix finally obtained it can be the DVB-S2 LDPC code shown in Figure 3, for example.

A code word can be generated by applying the DVB-S2 LDPC coding process described above, to the LDPC code designed by the previous steps.

To analyze the performance of the DVB-S2 LDPC code, a DVB-S2 LDPC code has been designed that has the following parameters. For example,

Nt = 64800, K1 = 38880, M1 = 360, q = 72

To design DVB-S2 LDPC codes with 3/5 rates having the above parameters, the parity check matrices shown in table 1 and table 2 can be obtained, for example, from a quasi-cyclic LDPC code that has a total of N1 / M1 = 180 blocks of columns and q = (N1-K1) / M1 = 72 blocks of rows, by applying the DVB-S2 LDPC code design process. A sequence of weighting-1 th in a ith column sequentially represents the information about the positions of rows with 1 in a group of ith columns.

Table 1

1443 3685 4728 5466 7771 9999 16155 17401 21311 21467 23168 24511 664 3974 5090 7327 8542 10468 11150 13508 17161 17754 19402 19447 2405 3298 3552 6482 11801 12626 14735 14828 16324 20133 21078 22381 658 3063 9064 1013 1289 1609 12169 1280 7528 9935 11629 12825 12966 17595 21024 21298 22559 24356 87 6396 8610 12968 13554 13692 15316 18113 18989 21291 23791 24092 8 217 1180 5344 5766 5971 8402 9481 9547 11091 12801 20487 7857 9024 9949 13571 13600 14884 21304 21301 214 14301 10794 12967 15336 16086 18241 19306 21213 22093 4167 4280 4929 4950 6643 9022 17030 17205 19445 20881 22678 24077 1812 6248 6683 7621 8726 13474 14664 15029 15949 20484 23069 24146 1553 4371 5291 7624 8369 12217 12502 12583 12573 8573 13870 15406 16869 19027 19980 24586 1818 1874 2110 4613 6487 7224 14155 14295 20169 20226 24628 25760 4220 6249 12431 15579 16982 17754 18174 18532 19503 20304 20718 20990 9 47 981 2068 2617 3542 6488 13023 15530 19507 19977 20722 21260 2814 4849 5829 7501 14442 15506 16426 17560 20680 21655 21920 23305 7 5115 7788 12129 13067 13711 14689 16032 20143 20446 20660 24232 1307 5173 7668 10268 10968 11101 1295 1401 2595 1625 8585 11357 12702 13287 14964 16610 18527 20961 21771 448 2453 5204 10643 11729 12590 14828 15422 16434 17543 19834 20231 6449 8048 8524 10455 13086 15586 16664 19441 20901 23170 25708 25859 6 1977 3407 3962 6229 7365 1189 4197 999 963 973 7193 973 7194 973 973 7194 963 973 7194 931 942 971 799 731 773 773 942 971 799 632 971 794 771 894 6524 6590 9245 9967 13008 14082 18454 18917

(continuation)

8 27 6373 7033 11751 18693 18861 21275 22883 24216 24366 24418 64 650 5561 7545 13030 15420 17359 18182 20500 21193 22374 23173 4122 5792 11210 5868 9919 10606 3548 9043 24036 10531 20824 24231 12974 16474 24561 6835 15985 17035 21983 1708 19587 21583 218 24814 388 5878 6620 4321 6685 12605 15532 18878 22727 95 4074 21010 24 1449 21095 5732 5787 21031 14052 21118 22883 1277 4555 15976 2131 14871 19508 26 16749 20090 6509 11083 18303 1828 2969 25240 1563 12973 17966 11905 13176 18515 10569 537

(continuation)

6330 19445 22931 12274 12966 13750 6545 13944 23585 2091 12976 24660 6501 18390 24255 3230 8792 12992 11530 12561 23764 524 2569 18992 6246 12960 13082 9933 21798 23789 10298 17400 25810 50 324 20781 6273 14253 11253 11253 11253 11253 23253 19452 19098 19465 22029 6524 13300 15645 10108 20846 22452 3028 6527 24879 1589 18042 20967 11794 19070 23250 6504 12992 15212 8 3171 7459 13355 15520 17438 12184 22327 24359

(continuation)

133 17306 22042 8623 11511 12971 2841 12934 23320 3875 13011 20825 11047 12966 25484 6491 7073 8539 6521 13861 19465 6545 15214 21454 9768 19472 21803 6546 8893 14660 1171 12973 23624 6482 8991 12988 13007 15030 19463 6511 15494 245512 24344 13034124 24344 13034124303 16529 13021 19079 21636 69 12963 13018 6506 6536 8224 3889 19054 19458 4787 4988 19469 24 5844 23621 11508 16029 19446 55 1042 6547 14398 14427 23730 38 49 19449

(continuation)

6544 13010 15495 4036 7734 12651 57 12981 22287

Table 2

1096 5305 7922 9029 9900 11901 13025 13052 13129 13325 13655 14723 1394 1860 6369 7264 8430 9676 10812 15647 18305 23208 23745 23826 770 2568 3964 5173 6526 6920 7003 10710 12819 15549 16488 25759 51 693 3004 9322 10614 581 581 581 581 581 231 241 231 8535 11633 12278 13266 14804 16227 18147 21946 22918 25486 3435 3718 4487 4955 5256 8584 12007 13417 14215 17230 19400 20982 844 1833 6682 6715 7028 9774 10242 16051 18866 22429 23751 24727 330 1481 2318 3851 4719 5306 4720 22831 12123 13390 16365 17923 19086 23028 23324 23984 515 3130 13252 14250 16261 16907 18400 18900 20512 22911 23030 23761 4449 6633 13133 16253 20114 21157 21213 21287 23287 23942 24401 24811 1365 1560 2416 3866 4743 6641 12645 12682 2868 209 429 986 946 893 873 946 893 873 893 873 893 946 893 863 893 893 863 893 893 893 842 893 842 893 893 842 893 893 842 898 823 920 898 823 920 898 823 893 898 823 893 898 823 898 823 893 823 10876 11528 12414 15516 19867 23249 2278 3803 3922 8045 10512 11485 11605 13057 19340 21857 21971 23766 2252 3454 5978 6040 8378 11319 12461 13080 16013 19436 20070 22569 2346 2879 7004 8175 8227 8589 8850 9291 12756 15786 16971 23159 81 1790 1976 3361 7529 7902 8299 11663 13327 14484 16468 20032 1284 3267 3647 4207 4834 5596 9554 11103 16921 20328 20697 23312 890 10978 12966 13432 16008 259 257 279 257 259 257 279 257 259 257 279 259 257 279 253 15433 15507 15786 19229 19941 20456 20638 21009 25255 25838 678 1316 1858 5998 7537 8281 10923 15597 17389 18691 22102 25100 5819 6861 10626 10992 11039 13808 16495 16523 17437 20789 23463 24419

(continuation)

468 1289 4394 10112 10247 11168 15397 22042 22099 24220 24531 25142 1558 3264 3909 4121 6949 7547 9255 9428 9978 14409 19324 23040 3270 7693 10988 11129 12729 13188 13226 13386 17316 17549 21330 23577 924 3985 7216 8509 899 1709 249 309 1709 249 309 1709 1709 14343 15335 16060 17746 18259 20225 21262 23463 23524 25807 13718 18101 23423 3179 16321 23323 11120 14943 15049 10879 19035 21668 2393 8558 22850 6706 19748 24659 10136 15125 20390 9513 15535 18696 3964 5032 12598 10243 203 237 203 773 233 203 1000 13632 13182 17324 21766 5786 9155 19620 8529 11438 17005 217 5946 25640 6123 9532 17184 8975 10931 16954 14656 16394 22092 6145 13246 22376

(continuation)

18444 18915 21312 2115 14365 24194 11032 18236 20659 14486 22575 24669 15679 20943 25653 6881 7592 20934 777 14645 22876 8470 11263 17125 11159 22718 24692 18809 22677 23161 6430 15890 19898 10721 15342 19723 627 1,227 1,227 1,227 1,227 1,227 1,227 1,227 1,227 1,291 1,227 1,291 1,227 1,291 1,227 1,291 1,227 1,291 1,291 1,297 1,291 1,291 1,297,127,127,191 1,297,191 14315 9504 17357 23204 16253 20890 24073 1876 16146 21682 5310 5571 22570 17297 19348 19472 7100 13243 18153 8567 16070 17399 4279 13069 20035 14532 22925 25387 3579 4166 12336

(continuation)

108 2130 7119 12189 13790 16122 12757 16705 25768 372 8248 18808 3107 10254 19423 3839 22965 23458 545 3895 10707 5271 11433 21752 798 1056 17532 471 754 15973 1425 11664 23858 20057 20639 21091 13907 14433 19007 16981 1609 16981 1609 17534 9800 10659 22341 13674 17377 17743 163 13792 19756 1421 12948 19238 2714 19233 25264 3113 15257 24463 2182 2532 9118 8647 12629 16846 3275 17252 18700 3529 18768 20538

(continuation)

2290 9906 11818 824 2180 10139 12309 17149 25813 2093 5279 20214 3843 19791 25029

In addition, a DVB-S2 LDPC code has been designed that has the following parameters. For example,

5 To design DVB-S2 LDPC codes with 3/5 rates having the above parameters, the parity check matrices shown in Tables 3 to 6 can be obtained, for example, from a quasi-cyclic LDPC code that has a total of N1 / M1 = 45 blocks of columns and q = (N1-K1) / M1 = 18 blocks of rows, by applying the DVB-S2 LDPC code design process. It should be noted that a sequence of weighting position-1 in a ith column sequentially represents the information on the positions of

10 rows with 1 in a group of ith columns.

Table 3

71 1478 1901 2240 2649 2725 3592 3708 3965 4080 5733 6198 393 1384 1435 1878 2773 3182 3586 5465 6091 6110 6114 6327 160 1149 1281 1526 1566 2129 2929 3095 3223 4250 4276 4612 289 1446 1602 2421 3559 3796 5590 5750 5763 6168 12277 2008 2020 2266 3365 3588 3867 4172 4250 4865 6290 3324 3704 4447 1206 2565 3089 529 4027 5891 141 1187 3206 1990 2972 5120 752 796 5976 1129 2377 4030 6077 6108 6231 61 1053 1781 2820 4109 5307

(continuation)

2088 5834 5988 3725 3945 4010 1081 2780 3389 659 2221 4822 3033 6060 6160 756 1489 2350 3350 3624 5470 357 1825 5242 585 3372 6062 561 1417 2348 971 3719 5567 1005 1675 2062

Table 4

659 1334 1693 1719 2350 3788 4895 5431 5742 6060 6108 6448 289 888 1831 2534 3463 4498 4644 4900 5219 5790 5807 6297 845 991 2062 2965 3317 3800 3864 4617 4695 4858 5138 5925 245 1065 1616 3372 3996 4263 4556 5110 6411 5732 1139 1525 2493 2995 3558 3952 4678 5328 5834 5982 197 240 656 1116 1576 2143 2445 2500 5079 5306 5376 6268 4468 5237 5679 751 4161 4667 1343 6014 6109 3445 3567 5589 2731 4932 5866 5 11283 565 42 3323 3392

(continuation)

2666 4713 6119 946 3479 4265 356 3010 5443 5469 6142 6319 3008 5768 6061 694 2127 3324 2225 3398 5310 1330 2007 3728 293 1989 6192 1349 2713 5119 879 1416 1770 1906 4414 5987 1382 2402 6069 2269 5136 5716

Table 5

237 688 782 1184 1683 1946 2681 3955 4458 4582 4709 5352 181 801 882 1771 2190 2427 3206 3569 3934 4553 5218 6344 158 555 1371 1429 1495 2713 3274 4450 4968 5982 5987 6287 196 694 1375 1863 2272 3383 3794 4124 4128 43594761 1494 2415 2746 3281 3311 4130 4191 5077 5236 6199 330 354 488 536 1045 1052 1527 2165 2349 2520 3865 4403 139 256 1015 1499 2148 2511 3056 3863 3871 4878 5096 5865 2361 3738 6118 431 1322 6382 4124 4264 5950 1329 1482 3097

(continuation)

293 584 3557 2740 3951 5612 1209 5305 5994 1568 3697 5651 1905 3514 3702 355 1348 4025 2220 4940 5270 653 2863 5903 1342 1699 6120 750 1575 3728 1043 1127 5763 1003 3352 5678 945 2993 3076 753 957 5731 2916 4008 4272 878 1396 3061

Table 6

242 1940 2093 3364 3493 3738 3952 5305 5443 5583 5708 6027 355 1348 1868 2382 2471 3702 3863 4438 5109 5188 5742 6266 1173 1635 2046 2076 2349 2879 3716 4118 4141 4495 4808 5320 978 1865 2199 2259 2684 4414 4570 4626 5139 5891 5826 581 581 581 581 584 1342 1381 1672 4008 5173 5260 5633 5652 6249 157 200 1472 2068 2201 2829 2852 3322 3429 3547 4302 6293 203 1575 2297 2347 2742 2810 5201 5311 5613 5637 6060 6142 786 1482 1487 1519 1707 1972 3793 4414 4591 5650 2393 6228 1526

(continuation)

3121 4263 5251 1631 2636 3371 1061 1146 4503 410 1374 2088 148 2270 4780 1675 3753 3787 3714 4589 6148 234 1222 5981 1328 2143 5250 1557 3526 3728 875 1347 5421 2006 3869 4684 2976 4027 6159 657 2916 4819 1416 3316 6405 212 1988 5888 353 5767 239 4123 5788

A performance comparison between the newly designed DVB-S2 LDPC code and the existing DVB-S2 LDPC code is shown in Figure 9. Figure 9 is a diagram showing a computer simulation result 5 of the DVB-S2 LDPC code, in accordance with an embodiment of the present invention.

It will be appreciated that when an additive Gaussian white noise channel (AWGN) uses a modulation scheme consisting of binary phase shift modulation (BPSK, Binary Phases Shift Key), a performance improvement of approximately 0 is made , 15 dB, at BER = 10-4. The performance improvement of a 3/5 rate DVB-S2 LDPC code can be achieved by simply changing information on

10 the parity check matrix shown in tables 1 to 6.

The DVB-S2 LDPC code design process described with reference to Figure 8 can be used, not only for the 3/5 code rate but also for other code rates. The DVB-S2 LDPC code was designed with the following parameters, as an example to design a DVB S2 LDPC code that has another code rate.

15 To design DVB-S2 LDPC codes with 2/3 rate having the above parameters, parity check matrices shown in Tables 7 to 10 can be obtained, for example, from a quasi-cyclic LDPC code that has a total of N1 / M1 = 180 blocks of columns and q = 60 blocks of rows, by applying the DVB-S2 LDPC code design process in Figure 8.

Table 7

1264 2463 2556 3073 4370 12739 15418 16124 19807 19841 21010 21125 21171 113 1852 3132 4996 5975 9197 9655 11694 13480 17613 18031 20266 20346 444 3661 3722 5295 7401 8545 9028 10608 11828 14216 15585 20012 20577 90 2079 6809 109 16189 1500 19379 20487 2281 4322 5742 6974 7537 8903 13268 13439 17747 19986 20312 21388 21514 271 1258 1720 1865 4339 7416 8198 8276 9832 14358 15553 15923 19689 467 3367 3840 4942 6852 7525 8146 12648 14794 16503 17426 18327 11161 11151 18357 18680 18734 19418 3500 7181 7332 7679 9399 10942 11205 12514 17057 17928 18245 18264 20196 187 961 1803 3439 3794 4518 8365 11201 14023 15238 16136 19487 20296 455 4544 5241 7450 9100 11606 11948 14433 14874 156281509 7349 7297 7349 7349 7349 7349349349349349349349349349349349349349359 17372 17631 18109 18267 18475 19273

1298 2951 17635

495 650 11677

653 6222 14805

2274 9690 9743

11297 12566 14567 7281 17654 18609 2473 4923 14331

8760 14044 16012

8090 8146 19442 3449 12890 14460 839 6233 7840

8056 12933 15269

8493 10366 12434 701 9649 19076 1398 10270 13605

4243 9339 12774

3696 7696 15628 243 3130 11099 2097 4649 11467

2312 12024 20290

261 617 13196 7141 9684 10778 3530 5765 8743

4289 7187 16359

2958 5334 16260 10522 11425 13137 15475 16902 19208

1641 9284 17750

16845 17701 19088 5056 17464 21164 6993 12521 13333

7204 12854 14335

2552 16078 21113 542 4952 18819 5740 12083 19726

7387 8400 14186

3517 19451 20524 2616 4435 17063 3732 6440 7141

13818 16533 17156

11543 12109 12852 3348 5781 20818 9088 9154 12468

1677 1816 3263

5479 13538 18909 7087 11933 17417 2869 4396 8334

(continuation)

13150 13303 19272

2812 10594 11226 2612 3810 17336 6532 9457 14387

4433 16449 17397

6067 13659 19220 4328 11051 16035 7824 15244 20490

2188 5399 6750

6052 15205 17475 14374 15355 19910 4762 5874 12092

1625 7808 13669

3867 8650 17070 786 2520 7181 3231 8278 11367

1550 13884 17080

12553 20803 21588 17949 18263 19304 617 1563 2558

397 1801 7368

2411 3051 3354 5927 8048 13352 13411 15600 20409

2078 6302 14741

12454 18224 18506 504 7858 10998 3199 10422 11726

1153 2182 12546

4764 12313 16627 5135 13350 13392 889 7870 17425

8916 10519 12615

2562 8849 13143 3267 5581 21485 255 4679 20435

2255 10785 10851

6887 14015 18545 2318 10942 16588 4184 5153 19022

11862 15991 19165

10191 10519 13960 1460 19516 21166 4031 5859 18296

10594 13083 18567

8780 11212 18703 4248 14884 19339 2069 3014 13605

9659 13315 19220

4451 10126 19926 3565 9362 19476 4761 7956 14946

4411 13061 16858

273 6075 16827 703 4291 20357

3702 7702 16415

5188 11832 21198 1154 6086 20199

4420 5825 8937

6631 12585 17797 3537 14257 1 7073

Table 8

1970 4567 4933 5884 6610 7776 10431 11744 13263 15185 15418 18761 19939 293 1566 2735 3136 3346 4434 6552 9213 9220 9655 10192 11551 12377 5545 5805 6688 7676 7737 10608 10821 13742 16155 16472 16644 18128 18961 131 1669 2487 1483 189909909 20099 20602 827 6988 7559 8262 8543 9157 12214 13501 14702 14886 17612 19568 20174 319 2949 3176 4458 4660 4693 6516 9358 9638 12451 17363 19072 20465 2247 3685 5887 8220 10161 11846 11866 12423 16968 19067 19932 20074 21262 71 2475 5382 1234 139 146 15231 15533 16538 17929 2064 2819 4476 4882 9394 11660 12948 14705 15977 19965 20172 20801 20859

(continuation)

187 356 2581 3794 4518 6079 8563 8698 10276 10345 10541 12483 18467 455 584 4674 5920 7810 10408 11606 12308 15484 16653 17882 18211 19101 329 1566 2026 3927 6673 9595 10251 12409 17357 18729 18992 19955 20017

2635 3398 12371

495 650 19537

8865 11142 14333

13050 14094 20783

9266 11297 21407 3141 17654 18609 2473 4923 21591

8760 12712 18364

6646 8090 11522 3449 6960 19670 839 7073 11080

2729 9916 19353

2866 4694 20733 1669 5981 10196 1398 3610 20085

5259 8623 12774

3696 11956 15388 3130 8939 21543 2097 4649 11467

2170 10952 21564

617 14721 21296 7141 9684 16118 3530 7325 10063

2129 7547 10119

2958 5334 16260 7617 13945 21502 15475 16902 19208

8721 10184 17750

12825 19088 19681 5056 17464 18584 573 5261 13333

10495 12854 21364

10438 14633 18512 542 4952 10059 10600 12083 19726

4087 5966 8400

6484 16837 19451 2616 4435 20843 2120 3732 9721

7616 17373 19278

5449 12852 16223 2988 13341 20818 9088 9274 12048

1816 8423 20097

3079 13538 18909 4253 13327 17417 4396 8334 14869

13150 14683 19272

10746 11554 11692 1312 13350 17336 6532 13357 14387

4433 16449 17397

6067 7299 12860 4328 11051 16035 1410 1824 15244

6750 7799 17848

15205 17595 21052 12410 15355 18334 562 5874 12092

7808 16309 16745

30 6670 11367 3401 17286 19020 3231 17338 21387

13600 13910 18384

7488 9943 12433 743 17624 19089 617 1563 9938

3301 19057 21168

2411 3354 15051 5927 8048 18092 13411 15600 20409

7301 17498 20702

3524 4834 13406 10998 13344 15958 3199 4782 17486

7522 12546 15253

12313 16627 18444 4775 13350 13392 7870 14029 17425

3576 10519 12555

10662 14883 17849 5581 9087 21485 8039 10875 20435

1115 6225 9591

1475 13967 18545 2318 5842 16588 5153 17924 19022

(continuation)

11971 12462 14005

10780 11479 15231 7486 8840 19516 1976 7899 15311

6334 8727 10383

472 14743 17420 1728 14224 19339 2069 3014 13605

1435 9659 15260

4126 4451 19926 9362 13645 19476 2241 7956 14946

4781 9118 12691

9153 12495 16827 4291 16063 20357

16595 16762 20022

9148 11832 21198 1154 6219 13646

8937 12665 15700

4951 5745 14797 1057 12357 17073

Table 9

2599 2998 3291 3793 4567 5644 7476 8945 9250 11630 12041 12344 19983 113 5946 6640 7426 7577 10233 10831 12335 15672 15976 17995 20152 20514 1944 3315 4168 6117 6661 8745 10508 10608 10821 11636 12212 15145 19082 5549 7899 10946 11962 2018 20589 21258 239 3726 7468 7981 10028 11317 12462 15272 17747 19262 19403 20174 21514 563 2018 3439 4693 5458 7056 9391 9665 9832 10569 13076 14598 18340 467 5607 5665 6934 8062 9706 10101 10572 12288 15067 16083 17520 20906 3197 15208 1590 1597 15253 18042 18224 18680 19454 2399 4145 4176 4659 6197 11205 12514 12620 17261 17928 20292 21384 21442 2716 3794 6478 7567 10083 10345 10541 13543 16561 16638 17876 19459 19487 2034 3004 6284 9100 11606 12393 13821 14548 14731 15790 2107 773 873 773 873 773 873 772 873 773 873 772 873 773 873 772 873 772 873 772 873 772 873 873 772 873 773 873 772 873 772 873 772 873 772 857 772 873 772 857 772 873 875 757 873 857 773 873 773 873 875 757 873 873 773 873 795 873 7546 13517 14409 17631 18089 18109

1871 17078 17635

650 3495 19537

13253 14562 21465

17010 18503 21534

4877 11066 14567 13694 17241 18609 8463 14331 19453

772 8760 14044

2450 8146 19442 3449 6960 19670 839 6233 11080

15796 17669 19353

9466 10514 20733 5801 8809 15536 1398 10270 18705

4303 9339 12774

3696 5116 15388 243 3130 11099 2097 4649 11467

(continuation)

9864 10810 18992

681 12437 13196 7141 8258 9684 3530 11143 16025

1649 11507 16359

4638 5334 16260 10462 13945 14037 11515 16902 19208

530 11504 17421

285 11341 19088 15496 17464 21164 573 12521 13333

3374 3415 20944

9653 12212 16078 11019 13382 21452 6803 19726 21100

7387 9000 18446

16837 19451 20524 2616 4435 18773 3732 7141 21140

4196 15198 17373

5063 6192 12109 5781 6528 20818 9088 9274 20868

1283 9297 11956

18458 18909 20899 3847 12353 14717 4396 8334 19189

252 7903 13630

2812 11226 11554 2812 13350 17336 6532 7897 14387

14813 16449 17397

6067 6800 15459 3555 4328 11051 1824 15244 17730

5399 12210 17848

11692 15205 17475 12410 14455 20434 4762 5874 7472

7808 10729 11165

1587 4410 5230 786 2520 19841 12831 17338 19527

9580 13910 15084

10333 12223 14508 743 4509 16724 1563 14138 14357

5317 6901 10368

2411 3354 14871 3467 8048 18092 13411 15600 20409

1802 8681 17498

2074 5744 16166 7858 10998 13344 3199 10422 11726

8593 12546 13042

16627 18444 19813 4775 10872 19350 889 7870 17425

679 5175 14436

3629 10662 13143 5581 7407 21485 1995 3599 14195

875 10551 10785

1475 15605 15767 2318 5722 19708 15764 18173 19022

2905 13651 20802

4699 5500 18891 8840 12796 21166 3956 15311 20379

1414 4143 14967

4912 8900 19663 4248 14884 21559 2069 3014 20265

3440 9659 13315

2206 4451 19926 9362 13645 17616 3366 7956 9681

3811 8441 16858

6867 9153 13395 703 4291 11777

3702 6622 16595

1392 8008 21198 219 13646 18614

5825 8937 17080

637 4951 12585 3537 14257 17073

Table 10

1798 2990 8470 9859 10627 10743 11271 12344 13993 14076 15185 15461 15784 455 3160 4973 9655 11973 16446 17717 19471 20034 20152 20266 20836 21072

(continuation)

321 3008 3315 10608 12212 13425 14216 15448 17244 17577 18205 18541 21542 409 1342 5051 7220 8083 8619 10047 10710 11546 15258 15989 16389 18179 1242 1866 2354 2912 3388 5194 6023 11522 12481 12577 14768 17747 20459 2589 2658 2816 3853 4625 1899 1125 988 981 18996 20320 2066 4383 5487 5785 6492 10161 10847 14794 16440 18427 19486 20088 20542 4358 5115 8693 8954 10964 12330 12791 13040 13860 14637 18042 19971 20269 3500 3899 4176 6521 6605 12317 14194 15339 17172 17928 20984 2132 476 3106 476 3106 476 3106 12123 14278 16645 16759 455 1084 4082 5980 6284 7854 9931 10833 11710 12386 19708 21368 21561 2886 4287 6673 7546 8312 8317 9055 10397 11409 15351 16415 16489 16769

2738 12371 17635

495 650 3877

653 14562 14805

990 2274 3983

7826 11297 14807 7281 8174 18609 2473 4923 12231

8760 14044 16012

8090 16306 19442 5789 6960 20030 839 6173 20260

8056 8429 19353

434 9706 21093 1669 6221 19076 1398 2325 10270

2139 4303 12774

3696 11956 14788 243 3730 11099 2097 11467 16709

24 6850 8132

2237 13196 20481 8498 9684 12961 3530 10063 16025

7187 10709 16359

9138 15960 16494 9445 13137 21502 15475 16902 19208

164 8721 17750

3465 17701 19088 5056 17464 21164 12521 13333 19233

12854 14335 20944

5372 8633 16078 5492 7922 11019 7540 12083 19726

446 4627 8400

15877 19451 20524 4435 5616 14003 3732 7141 21140

3273 7616 12798

5063 12109 12852 8901 13548 20818 6448 9694 20868

1816 13403 16677

6259 13538 18909 2573 17417 20347 4396 8334 19369

7903 13150 19272

11226 12574 2112 1230 2812 17336 2272 14387 20257

4433 16449 17397

8707 12860 21399 4328 11051 16035 1410 1824 15244

5399 8730 15748

5812 17475 19165 12410 15355 20614 4762 5874 14972

(continuation)

11165 16568 21349

30 3747 5230 786 2520 7181 3231 17338 21387

2630 14860 18384

12223 12433 21588 6669 17843 19304 617 1563 10298

3301 5028 11677

2411 3354 6891 5927 8048 143112 13411 15600 20409

12782 14741 17498

2074 5744 17726 7858 10998 13344 3199 10422 14006

742 1153 12546

6024 12313 16987 4775 6030 13392 889 7870 17425

739 10596 12615

4469 10662 13143 4347 5581 21485 255 3599 8495

1115 10551 21585

5075 6887 18545 2318 7822 16588 5153 6044 19022

6085 8791 12462

4420 5479 10191 4906 8840 9916 639 1196 3431

10227 13083 21274

5743 9172 17420 4248 19339 20404 1274 2069 13605

9659 13315 15260

7811 16246 19926 9362 10956 17125 7956 9681 14946

1891 5038 15641

9153 13395 13707 16891 18163 20357

16762 18695 19602

138 20052 21388 219 1154 13646

1180 5825 18717

637 7831 12585 3537 10837 17073

Figure 10 is a block diagram showing a structure of a transceiver in a communication system using the redesigned DVB-S2 LDPC code, in accordance with an embodiment of the present invention.

Referring to Fig. 10, a message u is introduced to an LDPC encoder 1011 in a transmitter 1010 before being transmitted to a receiver 1030. Next, the LDPC encoder 1011 encodes the input message u and provides the signal encoded by a modulator 1013. The modulator 1013 modulates the encoded signal and transmits the modulated signal s to the receiver 1030 through a wireless channel 1020. Next, a

10 demodulator 1031 at receiver 1030 demodulates the signal r transmitted by the transmitter 1010, and delivers the demodulated signal x to an LDPC decoder 1033. Next, the LDPC decoder 1033 calculates an estimate value of the message from the data received by The wireless channel

A detailed structure of a transmission apparatus in the communication system using the redesigned DVB-S2 LDPC code is shown in Figure 11. Figure 11 is a block diagram showing a structure of

A transmission apparatus using the redesigned LDPC code, in accordance with an embodiment of the present invention.

The transmission apparatus includes a controller 1130, an LDPC code parity checking matrix extractor 1110 and an LDPC 1150 encoder.

The LDPC code parity check matrix extractor 1110 extracts a check matrix from

20 LDPC code parity according to system requirements. The parity check matrix of LDPC code can be extracted from the sequence information shown in Tables 1 to 10, it can be extracted using a memory in which the parity check matrix is stored, it can be comprised in the apparatus of transmission or can be generated in the transmission apparatus.

Controller 1130 is adapted to determine a necessary parity check matrix based on

25 a code rate, a code word length or an information length, to meet the system requirements.

The LDPC encoder 1150 performs encoding based on the LDPC code parity check matrix information read by the 1130 controller and the LDPC code parity check matrix extractor 1110.

Fig. 12 is a block diagram showing a structure of a receiving apparatus according to the embodiment of the present invention.

Figure 12 shows a reception apparatus for receiving the signal transmitted from the communication system using the redesigned DVB-S2 LDPC code and retrieving data desired by the user from the received signal.

The receiving apparatus includes a controller 1250, a decision device 1230 of the parity check matrix, an extractor 1270 of the LDPC code parity check matrix, a demodulator 1210 and an LDPC 1290 decoder.

The demodulator 1210 demodulates a received LDPC code, and provides the demodulated signal to the decision device 1230 of the parity check matrix and the LDPC 1290 decoder.

The decision device 1230 of the parity check matrix, under the control of the 1250 controller, decides the parity check matrix of the LDPC code used in the system, based on the demodulated signal.

The controller 1250 provides the decision result from the decision device 1230 of the parity check matrix to the parity check matrix 1270 extractor LDPC and the LDPC decoder 1290.

The LDPC code parity check matrix extractor 1270, under the control of the 1250 controller, extracts the parity check matrix of the LDPC code required by the system, and provides the parity check matrix extracted to the LDPC 1290 decoder. As indicated above, the parity check matrix of the LDPC code can be extracted from the sequence information shown in Tables 1 to 10, it can be extracted using a memory in which the parity check matrix is stored, it can be be incorporated in the transmission apparatus or may be generated in the transmission apparatus.

The LDPC decoder 1290, under the control of the 1250 controller, performs decoding based on the received signal provided from the demodulator 1210 and the information of the parity check matrix of the LDPC code provided from the parity check matrix extractor 1270 of LDPC code.

An operational flow diagram of the receiving apparatus of Figure 12 is shown in Figure 13.

In step 1301, demodulator 1210 receives a signal transmitted from the communication system using the redesigned DVB-S2 LDPC code, and demodulates the received signal. Next, in step 1303, the decision device 1230 of the parity check matrix adopts a decision on a parity check matrix of the LDPC code used in the system, based on the demodulated signal.

The decision resulting from the decision device 1230 of the parity check matrix is provided to the LDPC code parity check matrix extractor 1270, in step 1305. The LDPC code parity check matrix extractor 1270 extracts an array for checking the parity of the LDPC code required by the system, and providing it to the LDPC decoder 1290, in step 1307.

As mentioned above, the parity check matrix of the LDPC code can be extracted from the sequence information shown in Tables 1 to 10, it can be extracted using a memory in which it is stored to the parity check matrix. , may be incorporated in the transmission apparatus or may be generated in the transmission apparatus.

Next, in step 1309, the LDPC decoder 1290 performs decoding based on the information on the parity check matrix of the LDPC code provided from the L70 code parity check matrix extractor 1270.

As is evident from the above description, the present invention uses characteristics of the Tanner graph in the design of the DVB-S2 LDPC code, thereby optimizing the performance of the communication system using the LDPC code.

While the invention has been shown and described with reference to a certain preferred embodiment thereof, those skilled in the art will understand that various changes in the form and details can be made therein without departing from the scope of the invention, such as defined by the appended claims.

Claims (6)

1. A method of decoding a channel in a communication system using a low density parity check code (LDPC), comprising the steps of: extract a parity check matrix from the LDPC code; Y 5 perform LDPC decoding using the extracted parity check matrix; in which the parity check matrix has N1 columns, where N1 is 16200 columns, the parity check matrix has an information part and a parity part, in which the information part has K1 columns, where K1 is 9720, and the parity part has a double diagonal shape and (N1-K1) columns, where (N1-K1) is 6480, in which the information part comprises a series of groups of columns, having 10 each group of columns M1 columns, where M1 is 360, and the number of groups of columns is K1 / M1, where K1 / M1 is 27; in which a code rate is 3/5, the position sequences of '1's in the 0 th column in the group of i-th columns, i = 0, ..., 26, indicated by  They are: 71 1478 1901 2240 2649 2725 3592 3708 3965 4080 5733 6198 393 1384 1435 1878 2773 3182 3586 5465 6091 6110 6114 6327 160 1149 1281 1526 1566 2129 2929 3095 3223 4250 4276 4612 289 1446 1602 2421 3559 3796 5590 5750 5763 6168 12277 2008 2020 2266 3365 3588 3867 4172 4250 4865 6290 3324 3704 4447 1206 2565 3089 529 4027 5891 141 1187 3206 1990 2972 5120 752 796 5976 1129 2377 4030 6077 6108 6231 61 1053 1781 2820 4109 5307 2088 5834 5988 3725 3945 4010 1081 2780 3389 659 2221 4822 (continuation) 3033 6060 6160 756 1489 2350 3350 3624 5470 357 1825 5242 585 3372 6062 561 1417 2348 971 3719 5567 1005 1675 2062 wherein a grade of the 0 th column in the ith column group is indicated by Di; in which the structure of the information part is made using the following rule: determine the position of rows with '1's, indicated by  through where q is an integer that satisfies q = (N1-K1) / M1 = 18. 2. A method of decoding a channel in a communication system using a low density parity check code (LDPC), comprising the steps of: 10 extract a parity check matrix from the LDPC code; Y perform LDPC decoding using the extracted parity check matrix; in which the parity check matrix has N1 columns, where N1 are 64800 columns, the parity check matrix has an information part and a parity part, in which the information part has K1 columns, where K1 is 38880, and the parity part has a double diagonal shape and (N1-K1) columns, 15 where (N1-K1) is 25950, in which the information part comprises a series of column groups, each group of columns having M1 columns, where M1 is 360, and the number of column groups is K1 / M1, where K1 / M1 is 108; in which a code rate is 3/5, the position sequences of '1's in the 0 th column in the group of i-th columns, i = 0, ..., 107, indicated by They are: 1096 5305 7922 9029 9900 11901 13025 13052 13129 13325 13655 14723 1394 1860 6369 7264 8430 9676 10812 15647 18305 23208 23745 23826 (continuation) 770 2568 3964 5173 6526 6920 7003 10710 12819 15549 16488 25759 51 693 3004 9322 10614 11173 14481 15351 17204 24347 24595 25066 5823 6733 8535 11633 12278 13266 14804 16227 18147 21946 22918 25486 3435 3718 4487 20 830 1200 134 818 898 1200 6682 6715 7028 9774 10242 16051 18866 22429 23751 24727 330 1481 2318 3851 4719 5306 11620 11809 13829 13992 19885 25341 2231 3656 4723 7860 12123 13390 16365 17923 19086 23028 23324 23984 515 3130 13252 14250 16261 16907 18900 13903 1393 20114 21157 21213 21287 23287 23942 24401 24811 1365 1560 2416 3866 4743 6641 12645 12802 13978 21478 22017 22564 996 1168 2095 2393 2846 4283 10876 11528 12414 15516 19867 23249 2278 3803 3922 8045 10512 11485 11605 13057 19340 21857 113 878 59878878 12461 13080 16013 19436 20070 22569 2346 2879 7004 8175 8227 8589 8850 9291 12756 15786 16971 23159 81 1790 1976 3361 7529 7902 8299 11663 13327 14484 16468 20032 1284 3 267 3647 4207 4834 5596 9554 11103 16921 20328 20697 23312 890 10978 12966 13432 16008 20137 20523 21172 23970 25157 25430 25759 7192 13142 15433 15507 15786 19229 19941 20456 20638 21009 25255 25838 678 1316 1858 5926 25981 898 6199 6189 6198 6199 6198 6199 6198 6169 6198 6198 6169 6198 6198 6169266 10992 11039 13808 16495 16523 17437 20789 23463 24419 468 1289 4394 10112 10247 11168 15397 22042 22099 24220 24531 25142 1558 3264 3909 4121 6949 7547 9255 9428 9978 14409 19324 23040 3270 7693 10988 11129 12729 13189169 9499 931 973 9366 13032 17083 17111 19413 24966 24970 2589 7528 14343 15335 16060 17746 18259 20225 21262 23463 23524 25807 13718 18101 23423 3179 16321 23323 (continuation) 11120 14943 15049 10879 19035 21668 2393 8558 22850 6706 19748 24659 10136 15125 20390 9513 15535 18696 3964 5032 12598 10242 23055 25367 650 7353 20597 3162 11002 23839 2153 3077 20395 683 1000 13632 13182 17324 21766 576 9266 256 795 256 957 256 17184 8975 10931 16954 14656 16394 22092 6145 13246 22376 18444 18915 21312 2115 14365 24194 11032 18236 20659 14486 22575 24669 15679 20943 25653 6881 7592 20934 777 14645 22876 (continuation) 8470 11263 17125 11159 22718 24692 18809 22677 23161 6430 15890 19898 10721 15342 19263 637 12008 19972 3327 14142 17132 6626 8278 17470 579 20337 25099 3141 13081 14315 9504 17357 23204 16253 20890 24073 1876 16143 2168 1924 13243 1924 13243 197 16703 13703 197 17399 4279 13069 20035 14532 22925 25387 3579 4166 12336 108 2130 7119 12189 13790 16122 12757 16705 25768 372 8248 18808 3107 10254 19423 3839 22965 23458 545 3895 10707 (continuation) 5271 11433 21752 798 1056 17532 471 754 15973 1425 11664 23858 20057 20639 21091 13907 14433 19007 16080 20032 24955 1398 14507 19154 6916 17780 24110 416 16393 17534 9800 10659 22341 13674 17377 17743 163 13792 19756 1421 12948 25384 213 318 258 313 9118 8647 12629 16846 3275 17252 18700 3529 18768 20538 2290 9906 11818 824 2180 10139 12309 17149 25813 2093 5279 20214 3843 19791 25029 wherein a grade of the 0 th column in the ith column group is indicated by Di; in which the structure of the information part is made using the following rule: determine the position of rows with '1's, indicated by where q is an integer that satisfies q = (N1-K1) / M1 = 72. 3. A method of decoding a channel in a communication system using a low density parity check code (LDPC), comprising the steps of: extract a parity check matrix from the LDPC code; Y perform LDPC decoding using the extracted parity check matrix; in which the parity check matrix has N1 columns, where N1 are 64800 columns, the parity check matrix has an information part and a parity part, in which the information part 10 has K1 columns, where K1 is 43200, and the parity part has a double diagonal shape and (N1-K1) columns, where (N1-K1) is 21600, in which the information part comprises a series of groups of columns, each group of columns having M1 columns, where M1 is 360, and the number of groups of columns is K1 / M1, where K1 / M1 is 120; in which a code rate is 2/3, the position sequences of '1's in the 0 th column in the group of 15 columns i-th, i = 0, ..., 119, indicated by are: 2599 2998 3291 3793 4567 5644 7476 8945 9250 11630 12041 12344 19983 113 5946 6640 7426 7577 10233 10831 12335 15672 15976 17995 20152 20514 1944 3315 4168 6117 6661 8745 10508 10608 10821 11636 12212 15145 19082 5549 7899 10946 11962 2018 20589 21258 239 3726 7468 7981 10028 11317 12462 15272 17747 19262 19403 20174 21514 563 2018 3439 4693 5458 7056 9391 9665 9832 10569 13076 14598 18340 467 5607 5665 6934 8062 9706 10101 10572 12288 15067 16083 17520 20906 3197 15208 1590 1597 15253 18042 18224 18680 19454 2399 4145 4176 4659 6197 11205 12514 12620 17261 17928 20292 21384 21442 2716 3794 6478 7567 10083 10345 10541 13543 16561 16638 17876 19459 19487 2034 3004 6284 9100 11606 12393 13821 14548 14731 15790 2107 773 873 773 873 773 873 772 873 773 873 772 873 773 873 772 873 772 873 772 873 772 873 873 772 873 773 873 772 873 772 873 772 873 772 857 772 873 772 857 772 873 875 757 873 857 773 873 773 873 875 757 873 873 773 873 795 873 7546 13517 14409 17631 18089 18109 1871 17078 17635 650 3495 19537 (continued) in which a grade of the 0 th column in the ith column group is indicated by Di; in which the structure of the information part is made using the following rule:

13253 1456221465

17010 18503 21534

4877 11066 14567 13694 17241 18609 8463 14331 19453

772 8760 14044

2450 8146 19442 3449 6960 19670 839 6233 11080

15796 17669 19353

9466 10514 20733 5801 8809 15536 1398 10270 18705

4303 9339 12774

3696 5116 15388 243 3130 11099 2097 4649 11467

9864 10810 18992

681 12437 13196 7141 8257 9684 3530 11143 16025

1649 11507 16359

4638 5334 16260 10462 13945 14037 11515 16902 19208

530 11504 17421

285 11341 19088 15496 17464 21164 573 12521 13333

3374 3415 20944

9653 12212 16078 11019 13382 21452 6803 19726 21100

7387 9000 18446

16837 19451 20524 2616 4435 18743 3732 7141 21140

4196 15198 17373

5063 6192 12109 5781 6528 20818 9088 9274 20868

1283 9297 11956

18458 18909 20899 3847 12353 14717 4396 8334 19189

252 7903 13630

2812 11226 11554 2812 13350 17336 6532 7897 14387

14813 16449 17397

6067 6800 15459 3555 4328 11051 1824 15244 17730

5399 12210 17848

11692 15205 17475 12410 14455 20434 4762 5874 7472

7808 10729 11165

1587 4410 5230 786 2520 19841 12831 17338 19527

9580 13910 15084

10333 12223 14508 743 4509 16724 1563 14138 14357

5317 6901 10368

2411 3354 14871 3467 8048 18092 13411 15600 20409

1802 8681 17498

2074 5744 16166 7858 10998 13344 3199 10422 11726

8593 12546 13042

16627 18444 19813 4775 10872 19350 889 7870 17425

679 5175 14436

3629 10662 13143 5581 7407 21485 1995 3599 14195

875 10551 10785

1475 15605 15767 2318 5722 19708 15764 18173 19022

2905 13651 20802

4699 5500 18891 8840 12796 21166 3956 15311 20379

1414 4143 14967

4912 8900 19663 4248 14884 21559 2069 3014 20265

3440 9659 13315

2206 4451 19926 9362 13645 17616 3366 7956 9681

3811 8441 16858

6867 9153 13395 703 4291 11777

3702 6622 16595

1392 8008 21198 219 13646 18614

5825 8937 17080

637 4951 12585 3537 14257 17073

determine the position of rows with '1's, indicated by  through 5 where q is an integer that satisfies q = (N1-K1) / M1 = 60. 4. An apparatus for decoding a channel in a communication system using a low density parity check code (LDPC), comprising: an LDPC code parity check matrix extractor to read a stored parity check matrix; Y 10 an LDPC decoder to perform LDPC decoding using the parity check matrix read; in which the parity check matrix has N1 columns, where N1 is 16200 columns, the parity check matrix has an information part and a parity part, in which the information part has K1 columns, where K1 is 9720, and the parity part has a double diagonal shape and (N1-K1) columns, where (N1-K1) is 6480, in which the information part comprises a series of groups of columns, having 15 each group of columns M1 columns, where M1 is 360, and the number of groups of columns is K1 / M1, where K1 / M1 is 27; in which a code rate is 3/5, the position sequences of '1's in the 0 th column in the group of i-th columns, i = 0, ..., 26, indicated by  They are: 71 1478 1901 2240 2649 2725 3592 3708 3965 4080 5733 6198 393 1384 1435 1878 2773 3182 3586 5465 6091 6110 6114 6327 160 1149 1281 1526 1566 2129 2929 3095 3223 4250 4276 4612 289 1446 1602 2421 3559 3796 5590 5750 5763 6168 12277 2008 2020 2266 3365 3588 3867 4172 4250 4865 6290 3324 3704 4447 1206 2565 3089 529 4027 5891 141 1187 3206 1990 2972 5120 752 796 5976 (continuation) 1129 2377 4030 6077 6108 6231 61 1053 1781 2820 4109 5307 2088 5834 5988 3725 3945 4010 1081 2780 3389 659 2221 4822 3033 6060 6160 756 1489 2350 3350 3624 5470 357 1825 5242 585 3372 6062 561 1417 2348 971 3719 5567 1005 1675 wherein a grade of the 0 th column in the ith column group is indicated by Di; in which the structure of the information part is made using the following rule: determine the position of rows with '1's, indicated by  through where q is an integer that satisfies q = (N1-K1) / M1 = 18. 5. An apparatus for decoding a channel in a communication system using a low density parity check code (LDPC), comprising: 10 an LDPC code parity check matrix extractor to read a stored parity check matrix; Y an LDPC decoder to perform LDPC decoding using the read parity check matrix; in which the parity check matrix has N1 columns, where N1 are 64800 columns, the parity check matrix has an information part and a parity part, in which the information part has K1 columns, where K1 is 38880, and the parity part has a double diagonal shape and (N1-K1) columns, where (N1-K1) is 25950, in which the information part comprises a series of groups of columns, each group of columns M1 having columns, where M1 is 360, and the number of column groups is K1 / M1, where K1 / M1 is 108; in which a code rate is 3/5, the position sequences of '1's in the 0 th column in the group of i-th columns, i = 0, ..., 107, indicated by They are: 1096 5305 7922 9029 9900 11901 13025 13052 13129 13325 13655 14723 1394 1860 6369 7264 8430 9676 10812 15647 18305 23208 23745 23826 770 2568 3964 5173 6526 6920 7003 10710 12819 15549 16488 25759 51 693 3004 9322 10614 581 581 581 581 581 231 241 231 8535 11633 12278 13266 14804 16227 18147 21946 22918 25486 3435 3718 4487 4955 5256 8584 12007 13417 14215 17230 19400 20982 844 1833 6682 6715 7028 9774 10242 16051 18866 22429 23751 24727 330 1481 2318 3851 4719 5306 4720 22831 12123 13390 16365 17923 19086 23028 23324 23984 515 3130 13252 14250 16261 16907 18400 18900 20512 22911 23030 23761 4449 6633 13133 16253 20114 21157 21213 21287 23287 23942 24401 24811 1365 1560 2416 3866 4743 6641 12645 12682 2868 209 429 986 946 893 873 946 893 873 893 873 893 946 893 863 893 893 863 893 893 893 842 893 842 893 893 842 893 893 842 898 823 920 898 823 920 898 823 893 898 823 893 898 823 898 823 893 823 10876 11528 12414 15516 19867 23249 2278 3803 3922 8045 10512 11485 11605 13057 19340 21857 21971 23766 2252 3454 5978 6040 8378 11319 12461 13080 16013 19436 20070 22569 2346 2879 7004 8175 8227 8589 8850 9291 12756 15786 16971 23159 81 1790 1976 3361 7529 7902 8299 11663 13327 14484 16468 20032 1284 3267 3647 4207 4834 5596 9554 11103 16921 20328 20697 23312 890 10978 12966 13432 16008 259 257 279 257 259 257 279 257 259 257 279 259 257 279 253 15433 15507 15786 19229 19941 20456 20638 21009 25255 25838 678 1316 1858 5998 7537 8281 10923 15597 17389 18691 2210225100 5819 6861 10626 10992 11039 13808 16495 16523 17437 20789 23463 24419 468 1289 4394 10112 10247 2442 2431 242 2431 242 (continuation) 1558 3264 3909 4121 6949 7547 9255 9428 9978 14409 19324 23040 3270 7693 10988 11129 12729 13188 13226 13386 17316 17549 21330 23577 924 3985 7216 8509 8931 9366 13032 17083 17111 19413 24966 24970 2589 7528 14343 189 1603 2346 233259 236 233 236 1603 236 233 239 23423 3179 16321 23323 11120 14943 15049 10879 19035 21668 2393 8558 22850 6706 19748 24659 10136 15125 20390 9513 15535 18696 3964 5032 12598 10242 23055 25367 650 7353 20597 3162 11002 23839 2153 3077 20395 683 1000 295 216 215 217 216 215 9205 5946 25640 6123 9532 17184 8975 10931 16954 14656 16394 22092 6145 13246 22376 18444 18915 21312 (continuation) 2115 14365 24194 11032 18236 20659 14486 22575 24669 15679 20943 25653 6881 7592 20934 777 14645 22876 8470 11263 17125 11159 22718 24692 18809 22677 23161 6430 15890 19898 10721 15342 19263 637 12008 19972 3327 14142 7277 217 931 927 950 931 927 731 927 9507 23204 16253 20890 24073 1876 16146 21682 5310 5571 22570 17297 19348 19472 7100 13243 18153 8567 16070 17399 4279 13069 20035 14532 22925 25387 3579 4166 12336 108 2130 7119 (continuation) 12189 13790 16122 12757 16705 25768 372 8248 18808 3107 10254 19423 3839 22965 23458 545 3895 10707 5271 11433 21752 798 1056 17532 471 754 15973 1425 11664 23858 20057 20639 21091 13907 14433 19007 16080 20032 24915 1398 4199 16989 22341 13674 17377 17743 163 13792 19756 1421 12948 19238 2714 19233 25264 3113 15257 24463 2182 2532 9118 8647 12629 16846 3275 17252 18700 3529 18768 20538 2290 9906 11818 (continuation) 824 2180 10139 12309 17149 25813 2093 5279 20214 3843 19791 25029 wherein a grade of the 0 th column in the ith column group is indicated by Di; in which the structure of the information part is made using the following rule: determine the position of rows with '1's, indicated by Error! File name not specified. through where q is an integer that satisfies q = (N1-K1) / M1 = 72. 6. An apparatus for decoding a channel in a communication system using a low density parity check code (LDPC), comprising: 10 an LDPC code parity check matrix extractor to read a stored parity check matrix; Y an LDPC decoder to perform LDPC decoding using the read parity check matrix; in which the parity check matrix has N1 columns, where N1 are 64800 columns, the parity check matrix has an information part and a parity part, in which the information part 15 has K1 columns, where K1 is 43200, and the parity part has a double diagonal shape and (N1-K1) columns, where (N1-K1) is 21600, in which the information part comprises a series of groups of columns, each group of columns having M1 columns, where M1 is 360, and the number of groups of columns is K1 / M1, where K1 / M1 is 120; in which a code rate is 2/3, the position sequences of '1's in the 0 th column in the group of 20 columns i-th, i = 0, ..., 119, indicated by are: 2599 2998 3291 3793 4567 5644 7476 8945 9250 11630 12041 12344 19983 113 5946 6640 7426 7577 10233 10831 12335 15672 15976 17995 20152 20514 1944 3315 4168 6117 6661 8745 10508 10608 10821 11636 12212 15145 19082 5549 7899 10946 11962 12090 17083 17847 18440 19631 20039 20089 20589 21258 (continuation) 239 3726 7468 7981 10028 11317 12462 15272 17747 19262 19403 20174 21514 563 2018 3439 4693 5458 7056 9391 9665 9832 10569 13076 14598 18340 467 5607 5665 6934 8062 9706 10101 10572 12288 15067 16083 17520 20906 311 1489 2790 3597 14820 15231 15255 15398 17333 18042 18224 18680 19454 2399 4145 4176 4659 6197 11205 12514 12620 17261 17928 20292 21384 21442 2716 3794 6478 7567 10083 10345 10541 13543 16561 16638 17876 19459 19487 2034 3004 6284 9100 11606 12393 13821 14548 14731 15790 16208 19442 21095 695 873 3607 757 360 773 18089 18109 1871 17078 17635 650 3495 19537 13253 14562 21465 17010 18503 21534 4877 11066 14567 13694 17241 18609 8463 14331 19453 772 8760 14044 2450 8146 19442 3449 6960 19670 839 6233 11080 15796 17669 19353 9480 10533 13709 9703 9303 3696 5116 15388 243 3130 11099 2097 4649 11467 9864 10810 18992 681 12437 13196 7141 8257 9684 3530 11143 16025 1649 11507 16359 4638 5334 16260 10462 13945 14037 11515 16902 19208 530 11504 17421 285 11341 19088 15493 12643 12493 12643 12443 12343 16078 11019 13382 21452 6803 19726 21100 7387 9000 18446 16837 19451 20524 2616 4435 18743 3732 7141 21140 4196 15198 17373 5063 6192 12109 5781 6528 20818 9088 9274 20868 1283 9297 11956 18458 18909 20899 3847 12353 14717 4396 8334 19189 252 7903 13630 2812 11226 11554 2812 13350 17336 6532 7897 14387 14813 16449 17397 6067 6800 15459 3555 4328 11051 1824 15244 17730 5399 12210 17848 11692 15205 17475 12410 14455 20434 4762 5874 7472 (continuation) 7808 10729 11165 1587 4410 5230 786 2520 19841 12831 17338 19527 9580 13910 15084 10333 12223 14508 743 4509 16724 1563 14138 14357 5317 6901 10368 2411 3354 14871 3467 8048 18092 13411 15600 20409 1802 8681 17498 2074 5744 16166 7858 10998 13344 3199 10422 11726 8593 12544 13042 4727 8759 889 17425 679 5175 14436 3629 10662 13143 5581 7407 21485 1995 3599 14195 875 10551 10785 1475 15605 15767 2318 5722 19708 15764 18173 19022 2905 13651 20802 4699 5500 18891 8840 12796 21166 3956 15311 20379 1414 4143 1967 4149 209 496 209149 9659 13315 2206 4451 19926 9362 13645 17616 3366 7956 9681 3811 8441 16858 6867 9153 13395 703 4291 11777 3702 6622 16595 1392 8008 21198 219 13646 18614 5825 8937 17080 637 4951 12585 3537 14257 17073 wherein a grade of the 0 th column in the ith column group is indicated by Di; in which the structure of the information part is made using the following rule: determine the position of rows with '1's, indicated by  through where q is an integer that satisfies q = (N1-K1) / M1 = 60.