KR20130044254A - Apparatus and method for channel encoding and decoding in communication system using low-density parity-check codes - Google Patents

Abstract

The present invention relates to a method and apparatus for channel encoding / decoding in a communication system. The present invention relates to a channel encoding for generating various codeword sizes from a structured LDPC code in a communication system using a low density parity check (LDPC) code. / Decryption method and apparatus. A channel coding method in a system using a low density parity check code, the method comprising: dividing information bits into a plurality of bit groups; Determining the number of information bits to be shortened; Determining the number of bit groups to be shortened based on the determined number of information bits to be shortened; Shortening the information bits of the determined bit group according to a predetermined order; And encoding the shortened information bits.

Description

Method and apparatus for channel encoding / decoding in a communication system using a low density parity check code {APPARATUS AND METHOD FOR CHANNEL ENCODING AND DECODING IN COMMUNICATION SYSTEM USING LOW-DENSITY PARITY-CHECK CODES}

The present invention relates to a communication system using a low-density parity-check (LDPC) code, and more particularly, to generate an LDPC code having various codeword lengths and code rates from a given LDPC code. A channel encoding / decoding apparatus and method are disclosed.

In a wireless communication system, the performance of a link is significantly degraded due to various noises, fading and inter-symbol interference (ISI) of a channel. Therefore, it is essential to develop overcoming techniques for noise, fading and ISI in order to realize high-speed digital communication systems requiring high data throughput and reliability, such as next generation mobile communication, digital broadcasting, and portable Internet. In recent years, error-correcting codes have been actively studied as methods for efficiently restoring information distortion and improving communication reliability.

Originally introduced by Gallager in the 1960s, the LDPC code has long been forgotten due to the complexity of implementation far beyond the technology of the time. However, since the turbo codes found by Berrou, Glavieux, and Thitimajshima in 1993 show performance close to the channel capacity of Shannon, many interpretations on the performance and characteristics of turbo codes have been made, and it has been studied a lot about iterative decoding and graph based channel coding. In the late 1990s, the LDPC code was re-studied and iterative decoding based on a sum-product algorithm on a Tanner graph (a special case of a factor graph) corresponding to the LDPC code was applied. It has been found that the performance is close to Shannon's channel capacity.

The LDPC codes are typically represented using graphical representations, and many features can be analyzed through graph theory, algebra, and probability-based methods. Generally, a graph model of a channel code is useful not only for describing codes but also to correspond information of encoded bits to a vertex in a graph and to correspond each bit relation to edges in a graph , It is possible to derive a natural decryption algorithm because each vertex can be regarded as a communication network for exchanging messages determined by each line. For example, the decoding algorithm derived from trellis, which is a kind of graph, includes the well-known Viterbi algorithm and BCJR (Bahl, Cocke, Jelinek and Raviv) algorithm.

The LDPC code is generally defined as a parity-check matrix and can be expressed using a bipartite graph collectively referred to as a Tanner graph. The bipartite graph indicates that the vertices constituting the graph are divided into two different types. In the case of the LDPC code, a binary graph composed of a variable node and a vertex called a check node Is expressed. The variable node corresponds one-to-one to the encoded bit.

A graph representation method of the LDPC code will be described with reference to FIGS. 1 and 2.

1 is an example of the parity check matrix H ₁ of the LDPC code consisting of four rows and eight columns. Referring to FIG. 1, since there are 8 columns, it means an LDPC code that generates a codeword having a length of 8, and each column corresponds to an encoded 8 bit.

FIG. 2 is a diagram illustrating a Tanner graph corresponding to H ₁ of FIG. 1.

Referring to FIG. 2, the Tanner graph of the LDPC code includes eight variable nodes x ₁ (202), x ₂ (204), x ₃ (206), x ₄ (208), x ₅ (210), x ₆ (212), x ₇ (214), x ₈ (216) and four check nodes (218, 220, 222, 224). Here, the i th column and the j th row of the parity check matrix H ₁ of the LDPC code correspond to the variable nodes x _i and j th check nodes, respectively. In addition, a value of 1, i.e., a non-zero value of a point where the i-th column and the j-th row of the parity check matrix H ₁ of the LDPC code intersect, refers to the variable node x _i on the Tanner graph as shown in FIG. An edge exists between and the j th test node.

In the Tanner graph of the LDPC code, the degree of the variable node and the check node means the number of line segments connected to each node, which is determined in the column or row corresponding to the node in the parity check matrix of the LDPC code. It is equal to the number of nonzero entries. For example, in FIG. 2, the variable nodes x ₁ 202, x ₂ 204, x ₃ 206, x ₄ 208, x ₅ 210, x ₆ 212, and x ₇ ( 214, and the order of x ₈ (216) is 4, 3, 3, 3, 2, 2, 2, 2, respectively, in order, and the order of test nodes 218, 220, 222, and 224, respectively, in order. 6, 5, 5, 5. In addition, the number of non-zero elements in each column of the parity check matrix H ₁ of FIG. 1 corresponding to the variable nodes of FIG. 2 is equal to the above-described orders 4, 3, 3, 3, 2, 2, and 2. , The same as 2, and the number of nonzero elements in each row of the parity check matrix H ₁ of FIG. 1 corresponding to the check nodes of FIG. 2 is the above-described orders 6, 5, 5, 5 In order.

In order to express the degree distribution for the nodes of the LDPC code, the ratio between the number of variable nodes with order i and the total number of variable nodes is called fi, and the number of check nodes with order j and the total number of check nodes is fi. Let the ratio of and g _{j be} . For example, for the LDPC code to the Figure correspond to the 1 and 2 is _{f 2 = 4/8, f} 3 = 3/8, f 4 = 1/8, i ≠ 2, 3, about 4 f _i = 0 and g _j = 0 for g ₅ = 3/4, g ₆ = 1/4, and j ≠ 5,6. When the length of the LDPC code is N, that is, the number of columns is N, and the number of rows is N / 2, the density of nonzero elements in the parity check matrix having the above degree distribution is expressed by Equation 1 below. Is calculated as

When N increases in Equation 1, the density of 1 in the parity check matrix continues to decrease. Generally, the LDPC code is inversely proportional to the nonzero element density with respect to the code length N, so that when N is large, the LDPC code has a very low density. The term low-density in the name of the LDPC code is derived for this reason.

Next, a characteristic of the parity check matrix of the structural LDPC code to be applied in the present invention will be described with reference to FIG. 3. FIG. 3 schematically illustrates an LDPC code adopted as a standard technology in DVB-S2, one of the European digital broadcasting standards.

은 LDPC 부호어의 길이이고,

은 정보어의 길이이고,

은 패리티 길이를 의미한다. 그리고,

이 성립하도록 정수

과

를 결정한다. 이때,

도 정수가 되도록 한다. 편의상 도 3의 패리티 검사 행렬을 제 1 패리티 검사 행렬 H₁이라 한다. Referring to Figure 3,

Is the length of the LDPC codeword,

Is the length of the information word,

Means parity length. And,

To establish this constant

and

. At this time,

Is also an integer. For convenience, the parity check matrix of FIG. 3 is referred to as a first parity check matrix H ₁ .

번째 열(column)부터

번째 열까지의 구조는 이중 대각(dual diagonal) 형태이다. 따라서, 패리티 부분에 해당하는 열의 차수(degree) 분포는 그 값이 '1'인 마지막 열을 제외하고 모두 '2'를 가진다. Referring to FIG. 3, a part corresponding to a parity part in the parity check matrix, that is,

From the first column

The structure up to the second column is a dual diagonal form. Therefore, the degree distribution of the column corresponding to the parity part has '2' except for the last column in which the value is '1'.

번째 열까지의 구조를 이루는 규칙은 다음과 같다.
In the parity check matrix, the portion corresponding to the information word portion, i.e.,

The rules for the structure up to the first column are as follows.

개의 열을

개의 열들로 구성된 복수 개의 그룹으로 그룹화(grouping)하여, 총

개의 열 그룹(column group)을 생성한다. 각 열 그룹에 속해있는 각각의 열을 구성하는 방법은 하기 규칙 2에 따른다. <Rule 1>: Corresponds to the information word in the parity check matrix

Columns

Grouping into multiple groups of columns

&Lt; / RTI &gt; column groups. How to configure each column belonging to each column group follows the rule 2.

번째

열 그룹의 각 0 번째 열에서의 1의 위치를 결정한다. 여기서, 각

번째 열 그룹의 0 번째 열의 차수를

라 할 때, 각 1이 있는 행의 위치를

이라 가정하면,

번째 열 그룹 내의

번째 열에서 1이 있는 행의 위치

는 하기 <수학식 2>와 같이 정의된다. <Rule 2>: First

th

Determine the position of 1 in each 0th column of the row group. Here,

Order of the 0th column of the 1st column group

Is the position of the row

Assuming that

Within the first column group

The position of the row with 1 in the third column

Is defined as in Equation 2 below.

번째

열 그룹 내에 속하는 열들의 차수는 모두

로 일정함을 알 수 있다. 상기 규칙에 따라 패리티 검사 행렬에 대한 정보를 저장하고 있는 DVB-S2 LDPC 부호의 구조를 쉽게 이해하기 위하여 다음과 같은 구체적인 예를 살펴보자. According to the rule above

th

The order of the columns belonging to the column group is

It can be seen that the constant. In order to easily understand the structure of the DVB-S2 LDPC code that stores information about the parity check matrix according to the above rule, let's look at the following specific example.

As a specific example, N ₁ = 30, K ₁ = 15, M ₁ = 5, q = 3, and 1 for the 0th column of the 3 column group (for convenience these sequences are referred to below as “weight-1 position sequences The position information of the row having a "" may be represented by three sequences as follows.

Regarding the position sequence of the row with the 0 th 1 of each column group, only the corresponding position sequences may be indicated for each column group as follows for convenience.

0 1 2

0 11 13

0 10 14

That is, the i th weight sequence position -1 in the i-th line shows the location of the line for the i th column group sequentially.

If the parity check matrix is configured using the information corresponding to the specific example and <Rule 1> and <Rule 2>, an LDPC code having the same concept as the DVB-S2 LDPC code shown in FIG. 4 may be generated.

It is known that the DVB-S2 LDPC code designed through <Rule 1> and <Rule 2> can be efficiently encoded using a structural form. Each step of the LDPC encoding process using the parity check matrix of the DVB-S2 will be described with the following example.

인 정보어 비트들을

로 나타내고, 길이가

인 패리티 비트들을

로 나타낸다. As a concrete example, a coding process using a DVB-S2 LDPC code characterized by N ₁ = 16200, K ₁ = 10800, M ₁ = 360, and q = 15 has been described. Also for convenience of description the length

Information bits

And the length is

Parity bits

Respectively.

. Step 1 : The encoder initializes parity bits.

.

Step 2 : The encoder calls the information of the row where 1 in the first column group of information words is located from the 0 th weight -1 position sequence of the stored parity check matrix.

0 2084 1613 1548 1286 1460 3196 4297 2481 3369 3451 4620 2622

를 이용하여 하기의 <수학식 3>과 같이 특정 패리티 비트

들을 업데이트한다. 여기서,

는 각각의

값을 의미한다. The called information and information bits

As shown in Equation (3) below,

Lt; / RTI &gt; here,

Respectively,

Lt; / RTI >

는

로 표기하기도 하며,

는 이진(binary) 덧셈을 의미한다. In Equation (3)

The

Sometimes referred to as

Means binary addition.

이후의 다음 359개의 정보어 비트

,

에 대해서 먼저 하기의 <수학식 4>에 대한 값을 구한다. Step 3 :

The following 359 information bits

,

First, the value for Equation 4 below is obtained.

는 각각의

값을 의미한다. 상기 <수학식 4>는 <수학식 2>와 동일한 개념의 수식임에 유의한다. In Equation (4)

Respectively,

Lt; / RTI &gt; It is noted that Equation 4 is an equation having the same concept as Equation 2.

에 대해서

을 업데이트한다. 예를 들어

, 즉,

에 대해서 하기의 <수학식 5>와 같이

들을 업데이트한다. Next, a similar operation to <Equation 3> is performed using the value obtained in Equation 4. In other words,

about

Update E.g

, In other words,

As shown below in Equation (5)

Lt; / RTI &gt;

임에 유의한다. 위와 같은 과정을

에 대해서 마찬가지로 진행한다. In the case of Equation 5

. Same process as above

Proceed similarly for.

에 대해서

의 정보를 독출하고, 특정

을 업데이트한다. 여기서,

는

을 의미한다.

이후의 다음 359개의 정보어 비트

에 대해서 <수학식 4>를 유사하게 적용하여

를 업데이트한다. Step 4 : 361th information word bit as in Step 2 above

about

Read information from, and

Update here,

The

.

The following 359 information bits

Equation 4 is similarly applied to

Lt; / RTI &gt;

Step 5 : Repeat the steps 2, 3 and 4 for all 360 groups of information word bits.

Step 6 : Finally, the parity bit is determined through Equation 6.

들이 LDPC 부호화가 완료된 패리티 비트들이다. In Equation (6)

These are parity bits for which LDPC encoding is completed.

As described above, in the DVB-S2, encoding is performed through the steps 1 to 6.

In order to apply the LDPC code to an actual communication system, the LDPC code must be designed to meet the data transmission amount required in the communication system. Especially, the communication system supporting various broadcasting services as well as the adaptive communication system applying the Hybrid Automatic Retransmission Request (HARQ) method and the Adaptive Modulation and Coding (AMC) method can meet the requirements of the system. Accordingly, LDPC codes having various codeword lengths are required to support various data transmission amounts.

However, as described above, the LDPC code used in the DVB-S2 system has only two types of codeword lengths due to its limited use, and requires an independent parity check matrix. For this reason, there is a need for a method that supports various codeword lengths to increase the scalability and flexibility of the system. In particular, in the DVB-S2 system, data transmission of hundreds to thousands of bits is required to transmit signaling information. Since only two DVB-S2 LDPC codes are 16200 and 64800, support for various codeword lengths is essential. .

In addition, storing an independent parity check matrix for each codeword length of an LDPC code reduces memory efficiency. Therefore, it is not necessary to design a new parity check matrix, and to efficiently convert various codeword lengths from a given parity check matrix. Support is needed.

The present invention provides a method and apparatus for channel encoding / decoding in a communication system using an LDPC code that generates an LDPC code having a different codeword length by using shortening or puncturing from a given LDPC code.

In addition, the present invention provides a method and apparatus for channel encoding / decoding in a communication system using an LDPC code that guarantees optimal performance in consideration of a DVB-S2 structure.

In accordance with another aspect of the present invention, there is provided a channel decoding method, comprising: demodulating a received signal in a channel decoding method in a system using a low density parity check code; Determining the location of the shortened information bits; And decoding the demodulated signal in consideration of the determined position of the shortened information bits, wherein determining the position of the shortened information bits comprises: determining a number of shortened information bits; Determining the number of shortened bit groups based on the determined number of shortened information bits; And obtaining a predetermined order of the bit groups.

According to an aspect of the present invention, there is provided a channel decoding apparatus including: a demodulator for demodulating a received signal in a system using a low density parity check code; A shortened pattern determiner which determines a position of a shortened information bit; And a decoder for decoding the demodulated signal in consideration of the determined position of the shortened information bits, wherein the determining of the position of the shortened information bits comprises: determining the number of shortened information bits; Determining the number of shortened bit groups based on the determined number of shortened information bits; And obtaining a predetermined order of the bit groups.

The present invention has the effect of substantially not using some heat by suggesting a short axis pattern. In addition, the present invention can generate a separate LDPC code having a different codeword length by using information of a given parity check matrix in a communication system using an LDPC code.

1 is a diagram showing an example of a parity check matrix of an LDPC code having a length of 8;
2 is a Tanner graph of an example of a parity check matrix of an LDPC code having a length of 8;
3 is a schematic structural diagram of a DVB-S2 LDPC code;
4 is a diagram showing an example of a parity check matrix of an LDPC code of DVB-S2 type;
5 is a block diagram of a transceiver of a communication system using an LDPC code;
6 is a flowchart for generating an LDPC code having a different codeword length from a parity check matrix of a stored LDPC code according to an embodiment of the present invention;
7 is a block diagram of a transmitter using a shortened LDPC code proposed in the present invention;
8 is a block diagram of a transmitter using a shortened / punched LDPC code proposed in the present invention;
9 is a block diagram of a receiver using an LDPC code to which a shortening proposed by the present invention is applied.
10 is a block diagram of a receiver using an LDPC code to which both shortening and puncturing proposed in the present invention are applied;
11 is a flowchart illustrating a receiving operation in a receiving apparatus according to an embodiment of the present invention.

Preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted so as not to obscure the subject matter of the present invention.

The present invention proposes a method for supporting an LDPC code having various codeword lengths using a parity check matrix of a specific type of structural LDPC code. In addition, the present invention proposes an apparatus and a control method supporting various codeword lengths in a communication system using a specific type of LDPC code. In particular, the present invention proposes a method and apparatus for generating a smaller LDPC code using a parity check matrix of a given LDPC code.

5 is a block diagram of a transceiver of a communication system using an LDPC code.

는 수신기(530)로 전송되기 전에 송신기(510)의 LDPC 부호화기(encoder)(511)로 입력된다. 그러면 상기 LDPC 부호화기(encoder)(511)는 입력된 메시지

를 부호화하여 출력한 부호화 신호를 변조기(Modulator)(513)로 전송한다. 상기 변조기(513)는 상기 부호화된 신호를 변조한 후 무선 채널(520)을 통해 수신기(530)로 전송한다. 그러면, 수신기(530)의 복조기(Demodulator)(531)는 상기 송신기(510)에 의해 전송된 신호를 복조한 후, LDPC 복호기(Decoder)(533)로 출력한다. 그러면, 상기 LDPC 복호기(533)는 무선 채널(520)을 통해 받은 데이터를 통해 메시지의 추정치(estimatation value)

를 추정해낸다. 5, the message

Is input to the LDPC encoder 511 of the transmitter 510 before being transmitted to the receiver 530. The LDPC encoder 511 then inputs an input message.

Transmits the encoded signal output by encoding the to the modulator (513). The modulator 513 modulates the encoded signal and transmits the modulated signal to the receiver 530 through the wireless channel 520. Then, the demodulator 531 of the receiver 530 demodulates the signal transmitted by the transmitter 510 and outputs the demodulated signal to the LDPC decoder 533. The LDPC decoder 533 then estimates the message through the data received through the wireless channel 520.

.

The LDPC encoder 511 generates a parity check matrix according to a codeword length required by the communication system in a preset manner. In particular, in the present invention, the LDPC encoder 511 may support various codeword lengths without the need for additional additional storage information by using the LDPC code. A detailed operation method of the LDPC encoder for supporting the various codeword lengths will be described in detail below with reference to FIG. 6.

6 is a flowchart illustrating an encoding operation of an LDPC encoder according to an embodiment of the present invention. That is, FIG. 6 is a flowchart illustrating a method for generating an LDPC code having a different codeword length from a parity check matrix of an LDPC code stored in advance.

In the present invention, a method of supporting various codeword lengths uses a method called shortening or puncturing.

The shortening means a method of substantially not using a specific portion of the parity check matrix for a given specific parity check matrix. In order to understand the shortening method, the parity check matrix of the DVB-S2 LDPC code of FIG. 3 will be described in detail.

이고, 앞부분은 길이가

인 정보어 비트들

이 대응되고, 뒷부분은 길이가

인 패리티 비트들

이 대응된다. 통상적으로 정보어 비트들은 0, 1의 값을 자유롭게 가지게 되는데 단축법에서는 단축시킬 특정 부분의 정보어 비트들의 값에 제한을 두게 된다. 예를 들어

에서부터

까지

개의 정보어 비트를 단축한다는 의미는 통상적으로

임을 의미한다. 다시 말하면,

에서부터

까지

개의 정보어 비트에 대한 값을 0으로 제한함으로써 상기 도 3의 DVB-S2 LDPC 부호의 패리티 검사 행렬에서 앞부분의

개의 열을 실질적으로 사용하지 않는 것과 동일한 효과를 얻게 되는 것이다. 단축법이라는 용어는 이러한 이유로 유래되었다. 따라서 본 발명에서 단축을 적용했다는 의미는 단축된 정보어 비트들의 값을 0으로 간주함을 의미하기도 한다. The parity check matrix of the DVB-S2 LDPC code of FIG.

The front part is

Information word bits

This corresponds, and the back part has a length

In parity bits

This corresponds. In general, information word bits have values of 0 and 1 freely. In the shorthand method, the information word bits of a specific part to be shortened are limited. E.g

From

Till

Shortening of information bits means

. In other words,

From

Till

By limiting the values of the four information word bits to 0, the preceding part of the parity check matrix of the DVB-S2 LDPC code of FIG.

You get the same effect as you don't actually use the dog's heat. The term shortening is derived for this reason. Therefore, the application of the shortening in the present invention also means that the value of the shortened information word bits is regarded as 0.

In the shortening method, when the system is configured, the location information of the information word bits shortened at the transmitter and the receiver may be shared or generated in the same manner, and thus the receiver may not be able to transmit the shortened bits. Decoding is performed while the information word bit is known to be 0.

이고, 정보어의 길이가

이므로 부호율이

이 되어 처음 주어진 부호율

보다 항상 작게 된다. In shorthand, the length of the codeword actually

The length of the information word

Since the code rate is

Is the first given code rate

Always smaller.

인 LDPC 부호어 중에서

개의 약속된 위치에 비트들을 단지 전송하지 않음으로써 길이가

인 LDPC 부호어를 전송하는 것과 동일한 효과를 얻는다. 패리티 검사 행렬에서 천공된 비트들에 해당하는 열들은 복호 과정에서 모두 그대로 사용되므로 단축법과는 차이가 있다. Next, the drilling method will be described in detail. The above puncturing method is generally applicable to both information word bits and parity bits. In addition, although the puncturing and shortening methods have in common that the codeword length of a code is shortened, unlike the shortening method, the puncturing method is not a concept of limiting a value of a specific bit. The puncturing method is a method of treating the receiver with an erasure by not transmitting a specific information word bit or a specific part of the generated parity bit. In other words, the length already created

LDPC codewords

By simply not sending bits to two promised positions

The same effect as transmitting an LDPC codeword is obtained. The columns corresponding to bits punctured in the parity check matrix are used as they are in the decoding process, which is different from the shorthand method.

Since the position information on the punctured bits can be shared or estimated by the transmitter and the receiver in the same time as the system is set, the receiver performs the decoding only by processing the punctured bits.

이고, 정보어의 길이는 변함없이

이므로 부호율이

이 되어 처음 주어진 부호율

보다 항상 크게 된다. The puncturing method is that the length of the codeword actually

The length of the information word

Since the code rate is

Is the first given code rate

Always bigger.

Now, a shortening method and a puncturing method suitable for DVB-S2 LDPC codes will be described. The DVB-S2 LDPC code is a kind of LDPC code having a specific structure as mentioned in the background art. Therefore, shortening and puncturing can be applied more efficiently than in the case of a general LDPC code.

,

인 DVB-S2 LDPC 부호로부터 단축법과 천공법을 통하여 우리가 최종적으로 얻고자 하는 LDPC 부호의 부호어 길이와 정보어 길이를 각각

,

이라 하자. 만일 우리가

,

라고 정의하면, DVB-S2 LDPC 부호의 패리티 검사행렬에서

비트만큼 단축을 취하고,

비트만큼 천공을 취하면 부호어 길이와 정보어 길이를 각각

,

인 상기 LDPC 부호를 생성할 수 있다. 이렇게 생성된 상기 LDPC 부호는

또는

일 때, 부호율이

가 되어 일반적으로 DVB-S2 LDPC 부호의 부호율

와는 다르게 되므로 대수적 특성이 변하게 된다. 여기서

인 경우에는 단축이나 천공을 모두 적용하지 않거나 또는 단축만 취한 경우에 해당된다. For convenience of explanation, the codeword length and information word length

,

The codeword length and information word length of the LDPC code that we finally obtain from the DVB-S2 LDPC code

,

. If we

,

Is defined in the parity check matrix of the DVB-S2 LDPC code.

Taking the bit as short as possible,

When puncturing bit by bit, the codeword length and information word length

,

The LDPC code may be generated. The generated LDPC code is

or

, The code rate is

Code rate of DVB-S2 LDPC code

And the algebraic characteristic is changed. here

If is not applied to both shortening or drilling or if only shortening is taken.

값이

개의 열에 대응되어 총

개의 열그룹(column group)이 각각 구조적인 형태를 가진다. 따라서 DVB-S2 LDPC 부호는 한 개의

값을 사용하지 않으면

개의 열을 사용하지 않는 것과 동일하다. 이러한 특징을 고려하여 다음과 같은 단축 과정을 제안한다. However, as described in Rule 1 and Rule 2, the DVB-S2 LDPC code has a single

The value is

Corresponding to ten columns

Each column group has a structural form. Therefore, the DVB-S2 LDPC code is one

If no value is used

This is equivalent to not using two columns. Considering these features, we propose the following shortening process.

와 정보어 길이

를 결정한다. 이후, LDPC 부호화기(511)는 저장되어 있는 패리티 검사 행렬의 호출된 정보로부터 요구되는 LDPC 부호의 정보어 길이에 맞는 단축을 취하는데, 하기 605 단계 내지 611 단계와 같은 단축 과정을 진행한다.First, the LDPC encoder 511 calls column group information of the DVB-S2 LDPC code to be shortened in step 601. That is, the stored parity check matrix information is called. After that, the LDPC encoder 511 may actually transmit a codeword length after the shortening in step 603.

And information word length

. Thereafter, the LDPC encoder 511 obtains a shortening corresponding to the information word length of the required LDPC code from the called information of the stored parity check matrix, and performs the shortening process as described in steps 605 to 611.

를 결정한다. 여기서

는

보다 같거나 작은 최대 정수를 의미한다.(605 단계) Shortcut Step 1 :

. here

The

The maximum integer is less than or equal to (step 605).

중에서

개의 열그룹에 대한 수열을 선택하고 이를

라 하자. 나머지

개의 열그룹에 대한 수열

는 없는 것으로 간주한다.(607 단계) Shortcut Step 2 :

Between

Select a sequence of columns

Let's say. Remainder

Sequence for groups of columns

Is considered to be absent (step 607).

개의

로부터 규칙 1과 규칙 2를 이용하여 단축된 DVB-S2 LDPC 부호를 생성한다. 이때 단축된 LDPC 부호는 정보어의 길이가

이 됨에 유의한다. 또한 이 값은 항상

보다 크거나 같다.(609 단계) Short Step 3 : Selected in Short Step 2

doggy

Rule 1 and rule 2 are used to generate a shortened DVB-S2 LDPC code. In this case, the shortened LDPC code has a length of information word.

Note that Also, this value is always

Greater than or equal to (step 609)

개의 열을 추가적으로 단축한다.(611 단계) Shortening Step 4 : In the shortened LDPC code generated in shortening step 3

Further reduce the number of rows (step 611).

,

,

,

의 특성을 가지는 DVB-S2 LDPC 부호를 이용하여 정보어 비트 중에서 12150 비트들을 단축하여 부호어 길이가

이며, 정보어의 길이가

인 새로운 LDPC 부호를 생성하는 과정을 다음에 자세히 나타낸다. To illustrate specific examples

,

,

,

Codeword length is reduced by shortening 12150 bits among information word bits using DVB-S2 LDPC code

And the length of the information word is

The process of generating a new LDPC code is described in detail below.

. Example of shortened step 1 :

.

중에서 4개의 열그룹에 대한 수열을 선택한다. 본 예에서는 아래와 같은 수열을 선택한다. Example of shortened step 2 : 37 total

Select the sequence for the four column groups. In this example, the following sequence is selected:

로부터 규칙 1과 규칙 2를 이용하여 단축된 DVB-S2 LDPC 부호를 생성한다. 이때 단축된 LDPC 부호는 정보어의 길이가

이 됨에 유의한다. Example of shortcut step 3 : four selected in the example of shortcut step 2

Rule 1 and rule 2 are used to generate a shortened DVB-S2 LDPC code. In this case, the shortened LDPC code has a length of information word.

Note that

Example of shortening step 4 : In the shortened LDPC code generated in the shortening step 3, 1440-1170 = 270 columns are further shortened.

The encoding is performed based on the shortened LDPC code as described above.

중에서

= 13320/360 - 4 = 33개의 열그룹에 대한 수열 정보를 사용하지 않으므로 단축 단계 2의 예에서는 총

비트를 단축한 것과 같다. 또한 단축 단계 3의 예와 단축 단계 4의 예를 통하여 다시 추가적으로 270 개의 정보어 비트를 단축하였으므로 최종적으로 12150 비트들의 정보어 비트를 단축한 것과 같다. 따라서 상기 실시 예에 따른 결과는

이며, 정보어의 길이가

인 단축된 LDPC 부호이다. According to the embodiment

Between

= 13320/360-4 = Since the sequence information for 33 column groups is not used,

It's like a shortened bit. In addition, through the example of the abbreviation step 3 and the example of the abbreviation step 4, an additional 270 information word bits are further shortened, which is equivalent to finally reducing the information word bits of 12150 bits. Therefore, the result according to the embodiment

And the length of the information word is

Is an abbreviated LDPC code.

As described above, in the present invention, unlike any bitwise shortening method commonly used for shortening of a DVB-S2 LDPC code, a structural group of the DVB-S2 LDPC code is used to assign a column group of the DVB-S2 LDPC code. Efficient abbreviation can be applied by using a method that does not use information.

In step 2 of the shortening process of the DVB-S2 LDPC code, the selection criteria of the sequence for the column group are briefly summarized as follows.

이며, 정보어의 길이가

인 일반적인 LDPC 부호의 최적의 차수 분포에 대하여 부호어 길이가

이며, 정보어의 길이가

인 DVB-S2 LDPC 부호에서 단축을 취하여 얻은 부호어 길이가

이며, 정보어의 길이가

인 단축된 LDPC 부호의 차수 분포가 거의 유사한 부호를 선택한다. <Reference 1>: Codeword length is

And the length of the information word is

The codeword length for the optimal order distribution of the general LDPC code

And the length of the information word is

Codeword length obtained by taking shortening from DVB-S2 LDPC code

And the length of the information word is

A code having a similar order distribution of the shortened LDPC code is selected.

<Criteria 2>: From the short codes selected in <Criteria 1>, select a cycle with good cycle characteristics on the Tanner graph. In the present invention, the cycle characteristic is selected when the minimum length cycle in the Tanner graph is the largest and the minimum number of the minimum length cycles is selected.

In <Reference 1>, an optimal order distribution of a general LDPC code may be obtained through a density evolution analysis method, but details thereof are omitted because they are not relevant to the gist of the present invention.

If the number of choices of weight-1 position sequence for the column group is not large, full search is performed for all cases irrespective of the two conditions such as <Criteria 1> and <Criteria 2> to obtain the best performance. The branch may select a sequence for the column group. However, the selection criterion for the column group applied in the step 2 of the DVB-S2 LDPC code satisfies the above two conditions when the number of selection branches of the weight-1 position sequence for the column group is too large. The efficiency can be increased by selecting the LDPC code.

DVB-S2 with N ₁ = 16200, K ₁ = 3240, M ₁ = 360, q = 36 for an example of a good sequence obtained by applying the selection criteria of the weight-1 position sequence for the column group to the column group Let's look at the sign. The DVB-S2 LDPC code has a weight-1 position sequence for the following column group.

6295 9626 304 7695 4839 4936 1660 144 11203 5567 6347 12557

10691 4988 3859 3734 3071 3494 7687 10313 5964 8069 8296 11090

10774 3613 5208 11177 7676 3549 8746 6583 7239 12265 2674 4292

11869 3708 5981 8718 4908 10650 6805 3334 2627 10461 9285 11120

7844 3079 10773

3385 10854 5747

1360 12010 12202

6189 4241 2343

9840 12726 4977

번째 열 그룹에 대한 1이 있는 행의 위치 정보를 순차적으로 나타낸 것이다. 따라서 상기 DVB-S2 LDPC 부호는 9개의 열그룹으로 구성되어 있음을 알 수 있으며, 정보어의 길이는 9ⅹ360 = 3240 임을 알 수 있다. 만일 단축을 취하여 얻고자 하는 부호어 길이 및 정보어 길이가 각각

,

라 하면, 단축 단계 1부터 단축 단계 4를 이용하여 최적화된 단축 패턴을 찾을 수 있음을 알 수 있었다. The i th weight -1 position sequence in the i line is

Positional information of a row with 1 for the first column group is sequentially displayed. Accordingly, it can be seen that the DVB-S2 LDPC code is composed of nine column groups, and the length of the information word is 9ⅹ360 = 3240. If the codeword length and the information word length to be obtained by shortening are respectively

,

In this case, it can be seen that the optimized shortening pattern can be found using the shortening step 1 to the shortening step 4.

,

의 값이 매우 가변적일 경우에는

의 값에 따라서 최적화된 단축 패턴이 상관성이 없을 수도 있다. 예를 들어 상기 DVB-S2 LDPC 부호에서 2개의 열그룹을 단축해야 할 경우에 최적의 선택은 4 번째, 8번째 열그룹의 1이 위치한 행에 대한 정보를 사용하지 않는 것이라 할 때, 3개의 열그룹을 선택할 경우에는 1, 5, 6번째 열그룹을 선택하여 단축하는 경우가 최적이 될 수도 있기 때문에 서로 연관성이 없다. 따라서 시스템에서 요구하는

,

의 값이 매우 가변적일 경우에는 최적화된 성능을 위해서는

값에 따라서 최적화된 단축 패턴을 모두 저장해야 된다는 단점이 있다. But if the system requires

,

If the value of is very variable

Depending on the value of, the optimized shortening pattern may not be correlated. For example, in the case where two column groups are to be shortened in the DVB-S2 LDPC code, the optimal choice is not to use information on the row where 1 of the fourth and eighth column groups is located. When selecting a group, it may be optimal to select and shorten the 1st, 5th, and 6th column groups, so they are not related to each other. So the system requires

,

If the value of is very variable for optimal performance

The disadvantage is that all optimized short patterns must be saved according to the value.

,

의 값이 매우 가변적일 경우에는 시스템의 효율성을 위해 다음과 같은 방법으로 준최적(suboptimal)의 단축 패턴을 찾을 수 있다. So if your system requires

,

If the value of is very variable, the suboptimal shortening pattern can be found in the following ways for system efficiency.

First, it is assumed that one column group needs to be selected for shortening. In this case, only one column group can be selected so that the best performing column group can be selected. Next, if you need to select two column groups for shortening, select the one that shows the best performance among the remaining ones, including the one you selected earlier. In the same way, if it is necessary to select i column groups for shortening, one column group having the best performance among the remaining column groups including the (i-1) column groups selected for the shortening in the previous step is selected do.

값의 변화에 무관하게 안정된 성능을 가질 수 있다는 장점이 있다. The method does not guarantee optimal selection, but from one short pattern

There is an advantage that it can have a stable performance regardless of the change in value.

,

의 값이 매우 가변적일 경우에는

,

에 따라서 다음의 <표 1>에 나타낸 9 가지 경우와 같은 준최적(suboptimal)의 단축 패턴 구할 수 있었다.(여기서 천공법은 고려하지 않았으므로

의 관계가 있음에 유의한다)Required by the system for specific examples

,

If the value of is very variable

,

As a result, suboptimal shortening patterns were obtained as shown in the following nine cases (Table 1).

Note that there is a relationship)

Range of K ₂ Shortening way

인 경우One)

If Eighth sequence row for the eighth column group among the weight-1 position sequences
6189 4241 2343
In the information word corresponding to

Shorten the bit. 2)

If Shorten all the column groups corresponding to the eighth sequence among the weight-1 position sequences, and in the case of the fourth column group, the fourth sequence
11869 3708 5981 8718 4908 10650 6805 3334 2627 10461 9285 11120
In the information word corresponding to

Shorten the bit further. 3)

If Shorten all the column groups corresponding to the 8th and 4th rows of the weight-1 position sequence, and in the case of the 7th column group, the 7th row in the information about the column group
1360 12010 12202
In the information word corresponding to

Shorten the bit further. 4)

If Shorten all column groups corresponding to 8th, 4th, and 7th row in the column group information, and 6th row in the information about the column group.
3385 10854 5747
In the information word corresponding to

Shorten the bit further. 5)

If Shorten all column groups corresponding to 8th, 4th, 7th and 6th rows in the column group information, and add a third row in the information about the column group.
10774 3613 5208 11177 7676 3549 8746 6583 7239 12265 2674 4292
In the information word corresponding to

Shorten the bit further.
6)

If Shorten all the column groups corresponding to the 8th, 4th, 7, 6th, and 3rd rows in the column group information, and the fifth row in the information on the column groups.
7844 3079 10773
In the information word corresponding to

Shorten the bit further. 7)

If Shorten all the column groups corresponding to the 8th, 4th, 7, 6th, 3rd, and 5th row in the column group information, and the second row in the information about the column group.
10691 4988 3859 3734 3071 3494 7687 10313 5964 8069 8296 11090
In the information word corresponding to

Shorten the bit further.
8)

If Shorten all column groups corresponding to 8th, 4th, 7th, 6th, 3rd, 5th, and 2nd rows in the column group information, and 9th row in the information on the column groups.
9840 12726 4977
In the information word corresponding to

Shorten the bit further. However, since a part of the column group corresponding to the ninth row corresponds to the 168-bit BCH parity bit by the DVB-S2 coding method, the column of the position corresponding to the BCH parity is not shortened.
9)

If In the column group information, all column groups corresponding to 8th, 4th, 7, 6th, 3rd, 5th, 2nd, and 9th rows are shortened, and the 1st row in the information on the column groups
6295 9626 304 7695 4839 4936 1660 144 11203 5567 6347 12557
528-K ₂ in the corresponding information word Shorten the bit further. If K ₂ = 168, this means that only a column corresponding to BCH parity remains in the DVB-S2 LDPC code.

The abbreviated order of <Table 1> is an order determined according to the <Reference 1> and the <Reference 2> to obtain the length of the information word in nine intervals as shown in the <Table 1>.

Referring to Table 1, it can be seen that shortening occurs sequentially for the 8th, 4th, 7th, 6th, 3rd, 5th, 2nd, 9th, and 1st column groups according to the size of the information word for the required LDPC code. have. That is, a value of 0 for an information word bit to be shortened in the order of columns corresponding to the 8, 4, 7, 6, 3, 5, 2, 9 and 1st raw according to the required information word size. Will be matched. In addition, if the shortening is explained differently, meaningful information word bits that are not fixed to 0 according to the length of the information word correspond to the order of 1, 9, 2, 5, 3, 6, 7, 4, 8th sequences. It can also be said. The sequence 8, 4, 7, 6, 3, 5, 2, 9, 1 indicates the first column as the 0th block, 7, 3, 6, 5, 2, 4, 1, 8, 0 and It may be written in the same form.

,

,

,

의 특성을 가지는 DVB-S2 LDPC 부호의 정보어 비트에 대응되는 부분에서 가장 마지막 열그룹인 9번째 열그룹(상기 수열 기준으로는 8번째 열그룹)의 마지막 168 비트는 BCH 패리티 비트가 대응되기 때문에 단축을 취할 수 없도록 되어 있음에 유의한다. 실제로

인 DVB-S2 LDPC 부호의 경우에는 상기

및

길이를 가지는 LDPC 정보어 비트(LDPC information bit)에 168 비트의 BCH 패리티 비트가 항상 포함되도록 설정되어 있다. Looking at steps 8) and 9) in <Table 1>,

,

,

,

Since the last 168 bits of the ninth column group (the eighth column group based on the sequence) correspond to the BCH parity bits in the portion corresponding to the information word bit of the DVB-S2 LDPC code having the characteristic of Note that no shortcut can be taken. in reality

In case of DVB-S2 LDPC code,

And

The LDPC information bit having a length is set to always include a 168-bit BCH parity bit.

In order to simply express the information of the shortened sequence as shown in Table 1, it is also shown as Table 2 below.

,

,

,

인 DVB-S2 부호에 대해서 살펴보자. 상기 DVB-S2 LDPC 부호는 다음과 같은 가중치-1 위치 시퀀스들을 가지고 있다. First to describe another specific embodiment

,

,

,

Let's look at the DVB-S2 code. The DVB-S2 LDPC code has the following weight-1 position sequences.

20 712 2386 6354 4061 1062 5045 5158

21 2543 5748 4822 2348 3089 6328 5876

22 926 5701 269 3693 2438 3190 3507

23 2802 4520 3577 5324 1091 4667 4449

24 5140 2003 1263 4742 6497 1185 6202

0 4046 6934

1 2855 66

2 6694 212

3 3439 1158

4 3850 4422

5 5924 290

6 1467 4049

7 7820 2242

8 4606 3080

9 4633 7877

10 3884 6868

11 8935 4996

12 3028 764

13 5988 1057

14 7411 3450

번째 행의 수열은

번째 열 그룹에 대한 1이 있는 행의 위치 정보를 순차적으로 나타낸 것이다. 따라서 상기 DVB-S2 LDPC 부호는 20개의 열그룹으로 구성되어 있음을 알 수 있으며, 정보어의 길이는 20ⅹ360 = 7200 임을 알 수 있다. 단축을 취하여 얻고자 하는 부호어 길이 및 정보어 길이가 각각

,

라 할 때, 다음 <표 3>과 같은 준최적화된 단축 패턴을 찾을 수 있다.
remind

The sequence of the first row is

Positional information of a row with 1 for the first column group is sequentially displayed. Accordingly, it can be seen that the DVB-S2 LDPC code is composed of 20 column groups, and the length of the information word is 20ⅹ360 = 7200. The codeword length and information word length to be obtained by shortening are respectively

,

In this case, we can find a suboptimal shortened pattern as shown in <Table 3>.

In the shortening process, additional shortening may be more easily implemented by sequentially performing the rear of the heat group in which the additional shortening is performed or sequentially performing the front.

After puncturing is necessary after step 611 in FIG. 6, the LDPC encoder 511 applies puncture in the LDPC encoding process in step 613. The drilling method is briefly described as follows.

,

인 DVB-S2 LDPC 부호로부터 단축법과 천공법을 통하여 우리가 최종적으로 얻고자하는 LDPC 부호의 부호어 길이와 정보어 길이를 각각

,

라 하고,

라고 정의하면, DVB-S2 LDPC 부호의 패리티 검사행렬에서

비트만큼 단축을 취하고,

비트만큼 천공을 취하면 부호어 길이와 정보어 길이를 각각

,

인 상기 LDPC 부호를 얻을 수 있었다. 이때 만일 편의를 위해 패리티 부분만 천공법을 적용한다고 가정할 때, 패리티의 길이는

이므로 패리티 비트에서

마다 1 비트씩 천공하는 방법이 있다. 하지만 천공법은 이러한 방법 외에도 다양한 방법을 적용할 수 있다. The codeword length and the information word length are respectively

,

The codeword length and information word length of the LDPC code that we finally obtain from the DVB-S2 LDPC code

,

,

Is defined in the parity check matrix of the DVB-S2 LDPC code.

Taking the bit as short as possible,

When puncturing bit by bit, the codeword length and information word length

,

The above LDPC code was obtained. If we assume that only the parity part is perforated for convenience, the length of parity is

In the parity bit

There is a method to drill 1 bit per time. However, the drilling method can be applied in addition to these methods.

인 경우에는 천공법을 적용할 필요가 없으며, 이때는 <표 1>에 나타낸 단축법 패턴을 이용하여 DVB-S2 LDPC 부호의 생성 방법과 유사하게 적용하면, 좋은 성능을 가지는 단축된 DVB-S2 LDPC 부호를 얻을 수 있다.

In the case of, it is not necessary to apply the puncturing method. In this case, when the analogous method is used to generate the DVB-S2 LDPC code using the shorthand pattern shown in Table 1, the shortened DVB-S2 LDPC code has good performance. Can be obtained.

An example is shown in FIG. 7 to show a transmission apparatus for realizing a shortening process of the DVB-S2 LDPC code in more detail. 7 is a block diagram of a transmitter using a shortened LDPC code according to an embodiment of the present invention.

The transmitting apparatus includes a control unit 710, a shortened pattern applying unit 720, an LDPC code parity check matrix extractor 740, and an LDPC encoder 760.

The LDPC code parity check matrix extractor 740 extracts the shortened LDPC code parity check matrix. The LDPC code parity check matrix may be extracted using a memory, may be given at a transmitter, or may be generated at a transmitter.

The controller 710 controls the shortened pattern applying unit 720 to determine a shortened pattern according to the length of the information word, and the shortened pattern applying unit 720 has a bit having a zero value at a position corresponding to the shortened bit. Or inserts a column corresponding to a shortened bit from a parity check matrix of a given LDPC code. In the method of determining the shortened pattern, a shortened pattern stored using a memory is used, a shortened pattern is generated using a sequence generator (not shown), or the density is evolved with respect to a parity check matrix and a given information word length. It can also be obtained using an analysis algorithm. The control unit 710 is a part of the information bits of the LDPC code of the low-density parity check code in the pattern shown in the <Table 1> to <Table 3> in the shortened pattern applying unit 720 Control to shorten.

The LDPC encoder 760 performs encoding based on the LDPC code shortened by the controller 710 and the shortened pattern applying unit 720.

8 and 9 are block diagrams showing a transmitter and a receiver of a DVB-S2 LDPC code that simultaneously apply shortening and puncturing.

First, FIG. 8 is a block diagram of a transmitter using a shortened / punched LDPC code according to the present invention.

The transmitter of FIG. 8 adds the puncturing pattern application unit 980 to the transmitter of FIG. 8. Referring to FIG. 8, it can be seen that the shortening is performed before the input of the LDPC encoder 860, and the puncturing is performed at the output stage of the LDPC encoder 760.

The puncturing pattern applying unit 880 applies puncturing to the output of the LDPC encoder 760. Since the method of applying the perforation has been described in detail with reference to step 613 of FIG. 6, the description thereof will be omitted.

9 is a block diagram of a receiver using an LDPC code to which a shortening is applied according to an exemplary embodiment of the present invention.

9 shows a user's desired signal from the received signal when receiving a signal transmitted in a communication system using the shortened DVB-S2 LDPC code and knowing the length of the shortened DVB-S2 LDPC code from the received signal. An example of a receiving device for restoring data is shown.

The receiving apparatus includes a controller 910, a shortened pattern determiner or estimator 920, a demodulator 930, and an LDPC decoder 940.

The demodulator 930 receives and demodulates the shortened LDPC code, and transfers the demodulated signal to the shortened pattern determiner or estimator 920 and the LDPC decoder 940.

The shortened pattern determination or estimator 920 estimates or determines information on the shortened pattern of the LDPC code from the demodulated signal under the control of the controller 910, and stores the shortened bit position information in the LDPC decoder ( 940). In the method of determining or estimating the shortened pattern by the shortened pattern determination or estimator 920, a shortened pattern stored using a memory is used, a shortened pattern is generated using a sequence generator (not shown), or the like. A parity check matrix and a given information word length may be obtained using a density evolution analysis algorithm.

Since the probability that the value of the shortened bit in the LDPC decoder 940 is 0 is 1 (that is, 100%), the controller 910 stores the shortened bits in the operation of the LDPC decoder 940 in the LDPC decoder 940. It is to determine whether to participate in the decoding or to participate in decoding by using the probability value 1 of 0 of the shortened bits.

When the LDPC decoder 940 knows the length of the DVB-S2 LDPC code shortened by the shortened pattern determination or estimator 920, the LDPC decoder 940 restores data desired by the user from the received signal.

10 is a block diagram of a receiver using an LDPC code to which shortening and puncturing is applied according to an exemplary embodiment of the present invention.

FIG. 10 is a form in which the shortening, puncturing pattern determining or estimating unit 1020 is replaced with the shortening pattern determining or estimating unit 920 of the receiving apparatus of FIG. 10.

The shortening, puncturing pattern determination or estimating unit 1020 may first perform pattern determination or estimation of a shortening at a receiving apparatus when both a shortening and puncturing are applied by a transmitting apparatus, or may first perform pattern determination or estimation on a puncturing. The pattern determination or estimation for shortening and the pattern determination or estimation for puncturing may occur simultaneously.

In addition, in the LDPC decoder 940, information about shortening and puncturing must be known at the same time so that decoding can be performed.

11 is a flowchart illustrating a receiving operation in a receiving apparatus according to an embodiment of the present invention.

The demodulator 930 receives and demodulates the LDPC code shortened in step 1101. The shortened pattern determination or estimator 920 then determines or estimates a shortened / punched pattern from the demodulated signal in step 1103.

The shortened pattern determination or estimator 920 determines whether there is a shortened or punctured bit in step 1105.

If the shortened or punctured bits do not exist, the LDPC decoder 940 performs decoding in step 1111. However, if there is a shortened or punctured bit, the shortened pattern determination or estimator 1020 transmits the position information of the shortened / punched bit to the LDPC encoder 940 in step 1107.

In step 1109, the LDPC decoder 940 sets the value of the shortened bit based on the position information of the shortened / punched bit to be 0, and sets the punctured bit to erasure. In step 1111, LDPC decoding is performed.

Claims (12)

In a channel decoding method in a system using a low density parity check code,
Demodulating the received signal;
Determining the location of the shortened information bits; And
Decoding the demodulated signal in consideration of the position of the determined shortened information bit;
Determining the location of the shortened information bit,
Determining a number of shortened information bits;
Determining the number of shortened bit groups based on the determined number of shortened information bits; And
And obtaining an order of a predetermined bit group.
The method of claim 1,
And determining the number of information bits that can be obtained by the shortening to determine the number of shortened information bits.
The channel decoding of claim 1, wherein the codeword length is 16200 and the information bit length is 3240, the predetermined order being 7, 3, 6, 5, 2, 4, 1, 8, 0. Way.
The method of claim 1, wherein when the codeword length is 16200 and the information bit length is 7200, the predetermined order is 18, 17, 16, 15, 14, 13, 12, 11, 4, 10, 9, 8 , 3, 2, 7, 6, 5, 1, 19, 0.
The method of claim 3,
If the length of the bit group is 360 and the length of the information bits is 3240,
Shortening the information bits of the bit group from the 0th bit group to the (m-1) th bit group according to the predetermined order; And
Shortening (3240-K ₂ -360m) information bits in the m-th bit group according to the predetermined order,
Where K ₂ is the number of information bits that can be obtained by shortening, and (3240-K ₂ ) is the number of information bits to be shortened,

Channel decoding method characterized in that.
5. The method of claim 4,
If the length of the bit group is 360 and the length of the information bits is 7200,
Determining that the information bits of the bit groups from the 0th bit group to the (m-1) th bit group are shortened according to the order of the predetermined bit group; And
Determining that (7200-K ₂ -360m) information bits in the m-th bit group are shortened according to the order of the predetermined bit group,
Where K ₂ is the number of information bits that can be obtained by shortening, 7200-K ₂ is the number of shortened information bits,

Channel decoding method characterized in that.
A channel decoding apparatus in a system using a low density parity check code,
A demodulator for demodulating the received signal;
A shortened pattern determiner which determines a position of a shortened information bit; And
A decoder which decodes the demodulated signal in consideration of the position of the determined shortened information bit;
The shortened pattern determination unit determines a location of the shortened information bits, determines the number of shortened information bits, and determines the number of shortened bit groups based on the determined number of shortened information bits, and And obtaining an order of a predetermined bit group.
The method of claim 7, wherein
And the shortening pattern determination unit further includes determining a number of information bits that can be obtained by shortening to determine the number of information bits to be shortened.
8. The method of claim 7, wherein if the codeword length is 16200 and the information bit length is 3240, the predetermined order is 7, 3, 6, 5, 2, 4, 1, 8, 0. Device.
8. The method of claim 7, wherein the codeword length is 16200 and the information bits are 7200, the predetermined order is 18, 17, 16, 15, 14, 13, 12, 11, 4, 10, 9, 8 And 3, 2, 7, 6, 5, 1, 19, and 0.
10. The method of claim 9,
If the length of the bit group is 360 and the length of the information bits is 3240,
The shortened pattern determination unit shortens the information bits of the bit group from the 0th bit group to the (m-1) th bit group according to the predetermined order, and (3240-) in the mth bit group according to the predetermined order. K ₂ -360m) shortening the information bits,
Where K ₂ is the number of information bits that can be obtained by shortening, (3240-K ₂ ) is the number of information bits to be shortened,

Channel decoding apparatus characterized in that.
The method of claim 10,
If the length of the bit group is 360 and the length of the information bits is 7200,
The shortened pattern determiner determines that the information bits of the bit group from the 0th bit group to the (m -1) th bit group are shortened according to the order of the predetermined bit group, and according to the order of the predetermined bit group. determining that the (7200-K ₂ -360m) information bits in the m th bit group are shortened,
Where K2 is the number of information bits that can be obtained by shortening, 7200-K ₂ is the number of shortened information bits,

Channel decoding apparatus characterized in that.

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