JP5612699B2 - Data transmission / reception method and apparatus in communication system - Google Patents

Description

  The present invention generally relates to communication systems, and more particularly, to a transmission / reception method and apparatus for obtaining a diversity effect.

  In wireless communication systems, link performance is significantly reduced due to various channel noises, fading phenomena, and inter-symbol interference (ISI). Therefore, techniques for overcoming noise, fading, and ISI to realize high-speed digital communication systems that provide high data throughput and reliability, such as next-generation mobile communication systems, digital broadcast systems, and portable Internet systems. It is important to develop. Recently, error correction codes have been actively researched to efficiently restore information distortion and improve communication reliability.

  LDPC codes first introduced in the 1960s were not generally realized due to implementation complexity far exceeding technology at the time. However, the performance of turbo codes discovered in 1993 in close proximity to Shannon's channel capacity, along with many interpretations of turbo code performance and characteristics, as well as many for iterative decoding and graph-based channel coding. The study was ongoing. As a result, LDPC codes were re-studied in the late 1990s, and iterative decoding based on a sum-product algorithm on a Tanner graph (a special case of a factor graph) corresponding to this LDPC code. Can be used to have a performance close to Shannon's channel capacity.

は、Ｋ_ldpc個の入力ビットを含む情報語

を受信及びＬＤＰＣ符号化することにより生成される。 An LDPC code is generally defined as a parity-check matrix and can be expressed using a bipartite graph called a Tanner graph. The LDPC code is used to receive an information word including K _ldpc bits or symbols and generate a code word including N _ldpc bits or symbols by LDPC encoding. For convenience of explanation, only a code word including N _ldpc bits generated by receiving and LDPC encoding an information word including K _ldpc bits will be described here. Codeword

Is an information word containing K _ldpc input bits

Is generated by receiving and LDPC encoding.

  That is, the code word is a bit stream including a plurality of bits, and the code word bit means a bit of the code word. Similarly, the information word is a bit stream composed of a plurality of bits, and the information word bit means a bit of the information word.

として生成される。ここで、

はパリティビットを表し、パリティビットの個数はＮ_parity＝Ｎ_ldpc-Ｋ_ldpcである。 For systematic codes, the codeword is

Is generated as here,

_Represents a parity bit, and the number of parity bits is N _parity = N _ldpc -K _ldpc .

  Since the LDPC code is defined by the parity check matrix, the sequence c satisfying the equation (1) is a code word for the LDPC code.

である。パリティ検査行列は、Ｎ_ldpc個の列を含み、ｉ番目の列はｉ番目の符号語ビットに関連することを意味する。 In equation (1),

It is. The parity check matrix includes N _ldpc columns, meaning that the i th column is associated with the i th codeword bit.

As described above, the LDPC code can be expressed in a bipartite graph based on the parity check matrix. This bipartite graph means that the vertices constituting the graph are divided into two different types. The LDPC code is represented by a bipartite graph including N _ldpc vertices called variable nodes and check nodes. The variable node has a one-to-one correspondence with the encoded bit, that is, the i-th variable node corresponds to the i-th codeword bit.

  FIG. 1 shows an example of a parity check matrix H of an LDPC code including 4 rows and 8 columns.

  Referring to FIG. 1, since the parity check matrix H has 8 columns each corresponding to 8 bits encoded, an LDPC codeword having a length of 8 is generated.

  FIG. 2 shows a Tanner graph corresponding to the parity check matrix H shown in FIG.

Referring to FIG. 2, the Tanner graph of the LDPC code includes eight variable nodes x ₀ 202, x ₁ 204, x ₂ 206, x ₃ 208, x ₄ 210, x ₅ 212, x ₆ 214, x ₇ 216 and Four check nodes 218, 220, 222, 224 are included. The i th column and the j th row of the parity check matrix H of the LDPC code correspond to the i th variable node x _i and the j th check node, respectively. Further, a value of 1 at a point where the i-th column of the parity check matrix H of the LDPC code and the j-th row intersect, that is, a non-zero value is represented by variable nodes x _i and j on the Tanner graph as shown in FIG. This means that there is an edge between the second check node.

  In general, an LDPC code is decoded using a Tanner graph. That is, the variable node and the check node generate messages and exchange them through their edges, thereby performing iterative decoding. Therefore, a correlation is formed between variable nodes connected to one check node, and this correlation must be taken into account during shortening and puncturing.

In the LDPC code Tanner graph, the degree of the variable node and check node indicates the number of edges connected to each node, and the non-zero entry of the column or row corresponding to that node in the parity check matrix of the LDPC code Is the same as the number of For example, in FIG. 2, the orders of the variable nodes x ₀ 202, x ₁ 204, x ₂ 206, x ₃ 208, x ₄ 210, x ₅ 212, x ₆ 214, x ₇ 216 are 4, 3, 3, respectively. 3, 2, 2, 2, and 2, and check nodes 218, 220, 222, and 224 are 6, 5, 5, and 5, respectively. The number of non-zero entries in the column of the parity check matrix H in FIG. 1 corresponding to the variable node in FIG. 2 is 4, 3, 3, 3, 2, 2, 2, 2, respectively. The numbers of non-zero entries in the corresponding row of the parity check matrix H of FIG. 1 are 6, 5, 5, and 5, respectively. Variable nodes have a one-to-one correspondence with codeword bits. Therefore, if the i-th variable node corresponds to the i-th codeword bit on a one-to-one basis, the order of the i-th variable node can be considered as the order of the i-th codeword bit.

The density of '1' decreases with increasing N _{ldpc in} the parity check matrix. In general, since the density of non-zero entries for an LDPC code is inversely proportional to the codeword length N _ldpc , an LDPC code having a large value for N _ldpc has a very low density. The use of “low density” in the name of the LDPC code comes from this reason.

  Since the LDPC code is defined by a parity check matrix, the system stores the parity check matrix to apply the LDPC code. In general, in order to store an LDPC code, position information having a weight of 1 is stored in a parity check matrix. However, since the code word length of an LDPC code used in an actual system reaches several hundred to several hundred thousand bits, in order to store position information of weight 1 when the code word length of the LDPC code is very long. The memory required for this is disadvantageous in that it is very large in capacity.

  In order to overcome such disadvantages, many studies on various LDPC codes having a specific configuration are in progress. In the case of an LDPC code having a specific configuration, the position of weight 1 is limited to the parity check matrix by a specific condition, so that the position of weight 1 can be stored more efficiently.

  FIG. 3 shows an example of an LDPC code having a specific configuration. Here, it is assumed that the LDPC code has a system configuration in which the code word includes an information word.

Referring to FIG. 3, the parity check matrix includes an information word part (or information word part) and a parity part. The information word part includes K _ldpc columns, and the parity part includes N _parity = N _ldpc −K _ldpc columns. The number of rows in the parity check matrix is N _ldpc -K _ldpc which is the same as the number of columns in the parity part.

に合うように決定され、

も整数である。Ｍ及びＱ_ldpcは、符号語長と符号化率により変わることができる。 Here, N _ldpc represents the length of the LDPC codeword, K _ldpc represents the length of the information word, and N _ldpc −K _ldpc represents the length of the parity part. The length of the code word means the number of bits included in the code word. Similarly, the length of the information word means the number of bits included in the information word. Furthermore, the integers M and Q _ldpc are

Determined to fit

Is also an integer. M and Q _ldpc can vary depending on the codeword length and coding rate.

In the parity check matrix shown in FIG. 3, the position of weight 1 from the K _ldpc th column to the (N _ldpc −1) th column, which is a part corresponding to the parity bit, has a double diagonal configuration. Have Therefore, it can be seen that the orders of the columns corresponding to the parity bits are all 2 except for the order of the (N _ldpc −1) -th column which is 1.

Referring to FIG. 3, in the parity check matrix, the portion corresponding to the information word, that is, the configuration from the 0th column to the (K _ldpc −1) th column is made according to the following rule.

個の列グループは、情報語に該当するＫ_ldpc個の列をＭ個の列ずつグルーピングして生成される。各列グループの列は、下記の規則２に従って生成される。 Rule 1: In the parity check matrix, the total

The column groups are generated by grouping K _ldpc columns corresponding to the information word by M columns. The columns of each column group are generated according to rule 2 below.

)の列グループの０番目の列で１の位置が決定される。各ｉ番目の列グループの０番目の列の次数がＤ_ｉで表されると仮定すると、１を有する行の位置が

である場合、ｉ番目の列グループ内のｊ番目(ｊ＝１，２，，Ｍ-１)の列で１を有する行の位置

は、下記の式(２)に示すように定義される。 Rule 2: i-th (

The position of 1 is determined in the 0th column of the column group. When the order of 0th column in each i th column group is assumed to be represented by D _i, the positions of rows with 1

The position of the row having 1 in the j th column (j = 1, 2, M−1) in the i th column group

Is defined as shown in Equation (2) below.

)の列グループ内の列の次数は、すべてＤ_ｉと同一である。 According to Rule 1 and Rule 2, i-th (

Order of the columns in column group) are identical to all D _i.

Hereinafter, a specific example will be described in order to more easily understand the configuration of an LDPC code that stores information on a parity check matrix according to the above rules. In the following specific example, when N _ldpc = 30, K _ldpc = 15, M = 5, and Q _ldpc = 3, the position information of the row having 1 in the 0th column of each of the three column groups is As shown below, it can be expressed by a sequence called “position sequence of weight 1”.

  For convenience, a weight 1 position sequence for a row position having a 1 in the 0th column of each column group is represented by column group as follows.

12810
0913
014

  That is, the i-th weight 1 position sequence represents the position information of the row having 1 in the i-th column group sequentially.

The LDPC code performs encoding and decoding on the number of bits of information K _ldpc and the number of bits of a code word N _ldpc . The number of parity bits N _parity is N _ldpc -K _ldpc . If the given number of information bits K _ldpc is larger than the number of information bits K _i input to the encoder, the information bits are transmitted by shortening by K _ldpc −K _i . When the required number of parity bits N _tx-parity = N _{tx_ldpc} -K _i is smaller than the number of parity bits N _parity , the parity bits are punctured by N _parity -N _tx-parity and transmitted. N _tx-parity represents the length of the parity bit actually used, and can be calculated based on the length K _i of the input information word and the coding rate required for transmission. Since the actual operation of shortening and drilling is not directly related to the embodiments of the invention described below, a detailed description of shortening and drilling is omitted.

  In some cases, the AWGN (Additive White Gaussian Noise) channel can guarantee very good performance when transmitting encoded data, but the fading channel may fail to obtain sufficient diversity. is there. Therefore, there is a need for a method that can overcome this problem.

Figure 4 illustrates a DVB-T2 (Digital Video Broadcasting he 2 nd Generation Terrestrial) system and DVB-NGH (Digital Video Broadcasting Next Generation Handheld) OFDM frame system.

  Referring to FIG. 4, each of the plurality of frames includes a plurality of OFDM symbols. One frame includes a P1 / P2 symbol portion and a data portion. The signaling information is mapped to the P1 / P2 symbol part, and this mapped information is transmitted in the P1 / P2 symbol part. Data other than the signaling information is mapped to this data portion and transmitted by a plurality of OFDM symbols. Therefore, this data signal is transmitted in a plurality of frames, and a sufficient diversity gain can be obtained. However, the signaling information has a problem in that performance deterioration is caused by not being able to obtain a sufficient diversity gain.

  Accordingly, in order to solve the above-described problems of the prior art, an object of the present invention is to provide a method and apparatus for transmitting data having a sufficient diversity gain.

  It is another object of the present invention to provide a method and apparatus for generating a parity codeword group having sufficient diversity gain.

  To achieve the above object, according to one aspect of the present invention, a method for transmitting data in a communication system is provided. The method includes a step of transmitting an information word included in a code word in a (k + s) th frame, a step of generating s groups based on a parity bit obtained by encoding the information word, and s pieces Transmitting in a distributed manner through s frames preceding the (k + s) th frame.

  According to another aspect of the present invention, a method for transmitting data in a communication system is provided. The method includes the steps of transmitting an information word included in a code word, an information word obtained by encoding the information word, and a bit not punctured from among parity bits punctured by a predetermined puncturing pattern through a (k + s) th frame. Selecting bits punctured in order according to a predetermined puncturing pattern to generate s groups, and transmitting s groups in a distributed manner through s frames preceding the (k + s) th frame. A step of performing.

  Furthermore, according to another aspect of the present invention, an apparatus for transmitting data in a communication system is provided. The apparatus includes an encoder for encoding an information word, a punch for punching a code word encoded by the encoder according to a predetermined punch pattern, and a parity bit punched by the punch from a code word output from the encoder. A parity group generator that selects and generates s groups, and an information word included in the codeword is transmitted in the (k + s) th frame, and a group of parity bits precedes the (k + s) th frame. And a transmission unit that transmits in a distributed manner through a plurality of frames.

  The present invention can obtain additional diversity gain by transmitting parity bits through multiple frames.

  The present invention also minimizes the use of additional modules in the encoding and decoding processes while increasing diversity gain by transmitting additional parity bits through multiple frames.

  The above and other aspects, features and advantages of embodiments according to the present invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings.

It is a figure which shows the parity check matrix of LDPC code whose length is 8. It is a figure which shows the Tanner graph corresponding to the parity check matrix of the LDPC code whose length is 8. It is a figure which shows the parity check matrix of the LDPC code used with a DVB-T2 system. It is a figure which shows the frame structure of a DVB-T2 / NGH system form. It is a figure which shows the frame structure by the rule 3 by embodiment of this invention. FIG. 6 is a diagram illustrating parity bits included in Q _ldpc groups according to an embodiment of the present invention. It is a figure which shows the frame structure based on the rule 4 by embodiment of this invention. It is a figure which shows the frame structure based on the rule 5 by embodiment of this invention. It is a figure which shows the frame structure based on the rule 5 by embodiment of this invention. It is a figure which shows the frame structure based on the rule 5 by embodiment of this invention. It is a figure which shows the frame structure of the DVB-T2 / NGH system by embodiment of this invention. It is a figure which shows the frame structure of the DVB-T2 / NGH system by other embodiment of this invention. It is a figure which shows the frame structure of the DVB-T2 / NGH system by other embodiment of this invention. FIG. 6 illustrates a method for selecting additional parity bits according to different embodiments of the present invention. FIG. 6 illustrates a method for selecting additional parity bits according to different embodiments of the present invention. FIG. 6 illustrates a method for selecting additional parity bits according to different embodiments of the present invention. 1 is a block diagram illustrating a transmission and reception apparatus according to an embodiment of the present invention. It is a block block diagram which shows the transmitter by embodiment of this invention. It is a block block diagram which shows the receiver by embodiment of this invention. It is a block block diagram which shows the transmitter by embodiment of this invention. It is a block block diagram which shows the receiver by embodiment of this invention. 3 is a flowchart illustrating a transmission method according to an embodiment of the present invention. 3 is a flowchart illustrating a reception method according to an embodiment of the present invention. FIG. 6 is a diagram illustrating various frame configurations according to different embodiments of the present invention. FIG. 6 is a diagram illustrating various frame configurations according to different embodiments of the present invention. FIG. 5 is a diagram illustrating a method for selecting an additional parity bit according to an embodiment of the present invention.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  In the following description, detailed features such as detailed configurations and elements are provided to aid in a comprehensive understanding of embodiments of the present invention. Accordingly, it will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. In addition, for the sake of clarity and conciseness, detailed descriptions of functions and configurations well known to those skilled in the art are omitted.

  Further, although the detailed description of the present invention will be described based on DVB-T2 system and DVB-NGH system, which are one of the European digital broadcasting standards, it is understood in the art that the present invention is not limited to these systems. It is obvious to those with normal knowledge. Moreover, although the present invention is described with a method for transmitting signaling information, it is not limited to transmission of signaling information.

  The codewords described below are two parts, a first part which is an information part containing an implementation information word and a second part which is a parity part containing additional information obtained by receiving and encoding the information word. Including the part. As mentioned above, codewords can be generated from data by drilling and shortening, if necessary.

  For convenience of explanation, it is assumed here that 'codeword' refers to an information word and all parity bits obtained by encoding the information word. That is, the parity bits include a parity bit that is not punctured and a parity bit that is punctured.

  If sufficient diversity gain cannot be obtained during transmission of the codeword, additional diversity gain can be obtained by transmitting data through multiple frames.

,

, ...,

である。この追加パリティビットは、特定規則によってグルーピングされる。 <Method 1>
The information word is transmitted in the zth frame. The additional parity bit is generated based on an information word and a parity bit that can be obtained by encoding the information word. The additional parity bits are transmitted through s frames. The group of additional parity bits transmitted in the associated frame is denoted by G (0), G (1),..., G (s-1), and the number of bits in each group is

,

, ...,

It is. This additional parity bit is grouped according to a specific rule.

  The “additional parity bit” means a parity bit transmitted in a frame different from the information word separately from the parity bit transmitted in the same frame as the information word.

As described above, the code is generated based on the (N _ldpc , K _ldpc ) code. Therefore, a puncturing pattern of parity bits adapted to the code can be calculated. However, a detailed description of the method for calculating the drilling pattern is omitted so as not to obscure the subject matter of the present invention.

“Parity bit puncturing pattern” means an index order of parity bits to be punctured. That is, if the number of parity bits to be punctured is N _punc = 2, N _punc = 2 elements are sequentially selected in the puncturing pattern, and parity bits having a value selected as an arbitrary index are punctured. . Assuming that the puncturing order or puncturing pattern set is A = {1, 5, 2, 6, 4, 0, 3, 7}, if the number of parity bits to be punctured is 2, then two indices 1 and 5 are sequentially selected in the drilling pattern set A. As a result, p ₁ and p ₅ are punctured from the parity bits p ₀ , p ₁ , p ₂ , p ₃ , p ₄ , p ₅ , p ₆ , p ₇ , and the remaining parity bits p ₀ , p ₂ , p ₃ , P ₄ , p ₆ and p ₇ are selected and transmitted as parity parts.

  For information words and parity bits, additional parity bits can be generated using rule 3 as shown below.

<Rule 3>
The additional parity bit can be selected from a parity bit and an information bit. The order of selecting additional parity bits from the parity bits is based on the puncturing order. At this time, the normal order or reverse order of the drilling pattern can be used. On the other hand, the additional parity bit is selected from information bits, and the information bits are selected in the order from which superior performance can be guaranteed.

  In general, bits concatenated in the order of the drilling pattern are generated to have a low correlation. That is, the order of the perforation pattern is determined so that even if two connected bits experience deep fading and are not easily restored, the restoration is easily realized by other bits. For example, if bits that are concatenated in the order of the drilling pattern or in reverse order are mapped to the same group and transmitted in the same frame, even if all the frames experience deep fading, they are recovered by other parity bits. It can be easily realized. Therefore, the restoration can be easily realized by selecting additional parity bits according to the order of the drilling pattern or the reverse order in the rule 3.

  In rule 3, the additional parity bits can be generated by first determining the order of the remaining bits, except for the bits to be punctured, and selecting the bits to be punctured after selecting the bits that are not punctured.

  If the additional parity bit is selected after all the bits to be punctured are selected in rule 3, the bits that can guarantee good performance are selected from the information bits and the parity bits using a greedy algorithm be able to. The greedy algorithm selects the highest performance bit of the codeword bits when selecting the first additional parity bit, and selects the first selected bit before when selecting the second additional parity bit. The selected bit is fixed, and the bit with the highest performance is selected from the remaining bits. The following must be considered when selecting high performance bits.

1) Order of variable node corresponding to codeword bit 2) Minimum cycle of variable node corresponding to codeword bit 3) Bit BER (bit error rate) performance of codeword bit

  Two embodiments for selecting additional parity bits using a greedy algorithm are described below, but various other methods are possible.

であり、これら値の和は

である。 In addition, the following description shows that the number of elements in the group of additional parity bits is

And the sum of these values is

It is.

<Embodiment 1>

  If the length of the parity part is greater than the sum of the number of elements in the group of additional parity bits, the group of additional parity bits is generated based on the parity bits of the codeword according to the order of the puncturing pattern.

  FIG. 5 shows a frame structure based on rule 3 according to an embodiment of the present invention.

Referring to FIG. 5, the codeword includes an information part and a parity part. For example, in FIG. 7, the length of the shortened information portion is 7 bits, I = {i ₀ , i ₁ ,..., I ₆ }, the length of the parity portion is 8 bits, P = {p ₀ , p ₁ , p ₂ ,..., p ₇ }, and the drilling pattern set meaning the drilling order is A = { ₁ , ₅ , ₂ , ₆ , 4, 0, 3, ₇ }.

(ここで、Ｎ_puncは穿孔ビットの個数であり、ｓは追加パリティビットが伝送されるフレームの個数であり、

はその関連したフレームで伝送される追加パリティビットの個数である。)である場合、追加パリティビットのグループは次のように生成される。 N _punc = 2, s = 3, and

(Where N _punc is the number of puncturing bits, s is the number of frames in which additional parity bits are transmitted,

Is the number of additional parity bits transmitted in the associated frame. ), The group of additional parity bits is generated as follows.

Since the number of bits to be drilled is 2, p ₁ and p ₅ are drilled by the drill pattern set A.

The elements included in the group of additional parity bits are determined from the bits p ₀ , p ₂ , p ₃ , p ₄ , and p ₆ according to the normal puncturing order except for the punctured bits p ₁ and p _5. , The first group is G (0) = {p ₂ , p ₆ }, the second group is G (1) = {p ₄ , p ₀ }, and the third group is G (2). = {P ₃ , p ₇ }. The first group is transmitted through the (k + 2) th frame, the second group is transmitted through the (k + 1) th frame, and the third group is transmitted through the kth frame.

On the other hand, when the elements included in the group of additional parity bits are determined in reverse puncturing order from the bits excluding the bits to be punctured, the first group has G (0) = {p ₇ , p ₃ }, The second group is G (1) = {p ₀ , p ₄ }, and the third group is G (2) = {p ₆ , p ₂ }. The first group is transmitted through the (k + 2) th frame, the second group is transmitted through the (k + 1) th frame, and the third group is transmitted through the kth frame.

  The determined groups are transmitted sequentially, but the transmission order of the groups can be changed.

<Embodiment 2>

  If the length of the parity portion is less than or equal to the sum of the number of elements in the additional parity bit group, the additional parity bit group is generated based on the parity bits and information bits of the codeword.

The code word includes an information part and a parity part. According to the embodiment as described above, the length of the shortened information part is 7 bits, I = {i ₀ , i ₁ ,..., I ₆ }, the length of the parity part is 8 bits, and P = { p ₀ , p ₁ , p ₂ ,..., p ₇ }, and the drilling pattern set indicating the drilling order is A = { ₁ , ₅ , ₂ , ₆ , ₄ , ₀ , ₃ , ₇ }.

(ここで、Ｎ_puncは穿孔ビットの個数であり、ｓは追加パリティビットが伝送されるフレームの個数であり、

はその関連したフレームで伝送される追加パリティビットの個数である。)である場合、追加パリティビットのグループは、次のように生成される。 N _punc = 2, s = 3, and

(Where N _punc is the number of puncturing bits, s is the number of frames in which additional parity bits are transmitted,

Is the number of additional parity bits transmitted in the associated frame. ), The group of additional parity bits is generated as follows.

Since the number of bits to be drilled is 2, p ₁ and p ₅ are drilled by the drill pattern set A.

Since the elements included in the group of additional parity bits are determined according to the normal puncturing order, the first group is G (0) = {p ₂ , p ₆ , p ₄ }, and the second group is G ( 1) = {p ₀ , p ₃ , p ₇ }, and the third group is G (2) = {p ₁ , p ₅ , i ₀ }. In particular, the third group includes previously drilled parity bits p ₁ , p ₅ and one bit i ₀ out of the codeword bits. The first group is transmitted through the (k + 2) th frame, the second group is transmitted through the (k + 1) th frame, and the third group is transmitted through the kth frame.

On the other hand, when the elements included in the group of additional parity bits are determined in the reverse puncturing order, the first group is G (0) = {p ₇ , p ₃ , p ₀ }, and the second group is G (1) = {p ₄ , p ₆ , p ₂ }, and the third group is G (2) = {p ₅ , p ₁ , i ₀ }. Similarly, the third group includes parity bits p ₅ and p ₁ punctured previously and one bit i ₀ among the codeword bits. The first group is transmitted through the (k + 2) th frame, the second group is transmitted through the (k + 1) th frame, and the third group is transmitted through the kth frame.

  The determined groups are transmitted sequentially, but the transmission order of the groups may change.

  Hereinafter, a method for generating a plurality of groups of additional parity bits based on the information word bits and the parity bits according to Rule 3 will be described in more detail.

In the case of the parity check matrix of the LDPC codeword shown in FIG. 3 having the codeword length N _ldpc and the information word length K _ldpc , the parity bits are represented by {p ₀ , p ₁ ,..., P _{Nldpc-Kldpc-1} }, and Q A group of _ldpc parity bits may be generated.

FIG. 6 illustrates parity bits included in Q _ldpc groups according to an embodiment of the present invention.

An index group indicating an index value of a parity bit included in the j-th group among the Q _ldpc groups is represented by the following equation (3).

  Based on Equation (3), an index group of parity bits for the puncturing pattern indicating the puncturing order can be calculated as shown in Equation (4) below.

That is, the (360 × j + i) -th element of the drilling pattern set A, which means the drilling order, is the same as the i-th element of I (π (j)) index groups. π (j) (0 ≦ j <Q _ldpc ) is defined as <Table 1> below.

  <Table 1> may be changed, for example, according to system requirements.

で表される場合、グループｌ(０≦ｌ＜ｓ)のパリティビットのインデックスグループは、次の式(５)により計算できる。 The number of bits to be punctured is represented by N _punc , and the number of elements in group l (0 ≦ l <s) is

In this case, an index group of parity bits of group l (0 ≦ l <s) can be calculated by the following equation (5).

個のインデックスは、穿孔パターンセットＡで穿孔されるパリティビットに対応するインデックスを除き、順次に選択される。 That is, the parity bits included in the l-th group of additional parity bits

The indexes are sequentially selected except for the index corresponding to the parity bit punctured in the puncturing pattern set A.

  Also, the parity bit index included in the group of additional parity bits may be selected in the reverse order of the puncturing pattern. In this case, the index group of the parity bit of the group l can be calculated using the following equation (6).

In equation (6), N _parity = N _ldpc -K _ldpc means the number of parity bits.

個のパリティビットのインデックスは、最後のビットから、穿孔順序を示すパターンセットＡの逆順で選択される。 That is, it is included in the l-th group of additional parity bits

The indexes of the parity bits are selected from the last bit in the reverse order of pattern set A indicating the puncturing order.

  Based on the index group calculated using Equation (5) or Equation (6), the elements of the parity bit group transmitted through a plurality of frames can be expressed as Equation (7) below.

In the formula (7), p _k denotes the k-th parity bit of the parity check matrix. Using equation (7), a parity bit having a value belonging to the l-th group C (l) of the index calculated in equation (6) is included in the l-th group C (l) of additional parity bits. .

  Therefore, Equation (7) generates a group that satisfies Rule 3.

<Rule 4>
The additional parity bits are generated by sequentially selecting the parity bits based on the parity bits and the information bits and mapping them in the order of the groups G (0), G (1),..., G (s-1). For the information bits, the more appropriate information bits are selected sequentially to provide better performance.

  In generating additional parity bits according to <Rule 4>, the order of the generated additional parity bits may be determined from the remaining bits, ie, bits that are not punctured. However, after selecting all bits that are not punctured, the bits that are punctured can be selected.

  In <Rule 4>, if additional parity bits have to be selected even after selecting all the punctured and non-punctured bits, the more suitable bits to provide better performance are Can be used to select from information bits and parity bits. The greedy algorithm selects the best performing bit of the codeword bits when selecting the first additional parity bit, and selects the first selected bit before selecting the additional parity bit. As a selected bit, the bit having the best performance is selected from the remaining bits. High performance bits must be considered as follows:

(1) Degree of variable node corresponding to codeword bit
(2) Minimum cycle of variable node corresponding to codeword bit
(3) BER (Bit Error Rate) performance of codeword bits

  In a parity check matrix having a parity portion of a double diagonal configuration, since the concatenated bits are connected to the same check node, there is a relation between the concatenated bits. Therefore, it is desirable that the concatenated bits are not transmitted through the same channel. Thus, the parity bits are sequentially mapped to different groups in order to experience different channels.

<Embodiment 3>
FIG. 7 shows a frame structure based on Rule 4 according to an embodiment of the present invention.

Referring to FIG. 7, the codeword includes an information part and a parity part. As described above, according to the same embodiment, after shortening, the length of the information portion is 7 bits, I = {i ₀ , i ₁ ,..., I ₆ }, the length of the parity portion is 8 bits, P = {P ₀ , p ₁ , p ₂ ,..., P ₇ }, and the drilling pattern set indicating the drilling order is A = { ₁ , ₅ , ₂ , ₆ , ₄ , ₀ , ₃ , ₇ }.

(ここで、Ｎ_puncは穿孔ビットの個数であり、ｓは追加パリティビットが伝送されるフレームの個数であり、

はその関連したフレームで伝送される追加パリティビットの個数である。)である場合、追加パリティビットのグループは、次のように生成される。パリティ部分に対応するパリティ検査行列の構成は二重対角行列である。 N _punc = 2, s = 3, and

(Where N _punc is the number of puncturing bits, s is the number of frames in which additional parity bits are transmitted,

Is the number of additional parity bits transmitted in the associated frame. ), The group of additional parity bits is generated as follows. The configuration of the parity check matrix corresponding to the parity part is a double diagonal matrix.

Since the number of bits to be drilled is 2, p ₁ and p ₅ are drilled by the drill pattern set A.

Since the parity bits are sequentially mapped to each group according to Rule 4, the parity bits that are not perforated, i.e. _{p 0, p 2, p 3} , p 4, p 0 from the p 6, _{p 7} the first group , _{p 2} is the second group, _{p 3} in the third group, _{p 4} is the first group, _{p 6} in the second group, _{p 7} in the third group are respectively mapped . As a result, the first group is G (0) = {p ₀ , p ₄ }, the second group is G (1) = {p ₂ , p ₆ }, and the third group is G ( 2) = {p ₃ , p ₇ }. The first group is transmitted through the (k + 2) th frame, the second group is transmitted through the (k + 1) th frame, and the third group is transmitted through the kth frame. The determined groups are transmitted sequentially, but the transmission order of the groups may change.

<Embodiment 4>
The length of the information part after shortening is 7 bits, I = {i ₀ , i ₁ ,..., I ₆ }, the length of the parity part is 8 bits, and P = {p ₀ , p ₁ , p ₂ ,..., P ₇ }, and the drilling pattern set indicating the drilling order is A = {1, 5, 2, 6, 4, 0, 3, ₇ }.

(ここで、Ｎ_puncは穿孔ビットの個数であり、ｓは追加パリティビットが伝送されるフレームの個数であり、

はその関連したフレームで伝送される追加パリティビットの個数である。)である場合、追加パリティビットのグループは、次のように生成される。パリティ部分に対応するパリティ検査行列の構成は二重対角行列であると仮定する。 N _punc = 2, s = 3, and

(Where N _punc is the number of puncturing bits, s is the number of frames in which additional parity bits are transmitted,

Is the number of additional parity bits transmitted in the associated frame. ), The group of additional parity bits is generated as follows. It is assumed that the configuration of the parity check matrix corresponding to the parity part is a double diagonal matrix.

Since the number of bits to be drilled is 2, p ₁ and p ₅ are drilled by the drill pattern set A.

は、パリティビットの個数、すなわち８より大きいので、最後のグループに含まれるビットは、情報ビットから選択される。すなわち、第１のグループはＧ(０)＝{ｐ_０，ｐ_４，ｐ_１}、第２のグループはＧ(１)＝{ｐ_２，ｐ_６，ｐ_５}、第３のグループはＧ(２)＝{ｐ_３，ｐ_７，ｉ_０}である。 The number of additional parity bits that form the group

Is greater than the number of parity bits, ie, 8, the bits included in the last group are selected from the information bits. That is, the first group is G (0) = {p ₀ , p ₄ , p ₁ }, the second group is G (1) = {p ₂ , p ₆ , p ₅ }, and the third group is G (2) = {p ₃ , p ₇ , i ₀ }.

  The first group is transmitted through the (k + 2) th frame, the second group is transmitted through the (k + 1) th frame, and the third group is transmitted through the kth frame. The determined groups are transmitted sequentially, but the transmission order of the groups may change.

  Hereinafter, a method for generating additional parity bits according to another embodiment of the present invention will be described.

  Transmit non-punctured parity bits and information words in the same frame, and transmit additional parity bits in other frames to obtain additional diversity gain, thereby obtaining diversity gain while reducing the actual coding rate be able to.

  For convenience of explanation, here, 'code word' refers to an information word and all parity bits obtained by encoding the information word. That is, the parity bit includes both a parity bit that is not punctured and a parity bit that is punctured.

<Method 2>
Parity bits that are not punctured are transmitted in the z-th frame, which is the same frame as the information word, and are included in the groups G (0), G (1),..., G (s-1) according to a specific rule. The additional parity bits obtained from the word and parity bits are transmitted in s frames.

  The additional parity bit means a bit transmitted in the previous frame instead of being transmitted in the same frame as the information word except for a parity bit transmitted in the same frame as the information word. G (0), G (1),..., G (s-1) means a group of additional parity bits.

<Rule 5>
The additional parity bit is selected from a parity bit and an information word bit, and a parity bit that is not transmitted in the same frame as the information bit is preferentially selected. Parity bits that are not transmitted in the same frame as the information bits are punctured parity bits. When the additional parity bits are selected from the parity bits, the order in which the additional parity bits are selected is determined by the normal or reverse order of the puncturing pattern. Among information bits, information bits that are likely to have better performance are sequentially selected.

  In generating an additional parity bit according to rule 5, a parity bit that is not transmitted in a frame in which an information bit is transmitted, that is, a punctured parity bit is first selected as an additional parity bit. After all these parity bits are selected, the information bits and parity bits from the code word are selected as additional parity bits.

  In Rule 5, if all parity bits to be punctured must be selected and then additional parity bits must be selected, then the bits that can provide better performance are the greedy algorithm from the information bits and parity bits of the codeword. Can be selected. As noted above, the greedy algorithm selects the best performance of the codeword bits when selecting an additional parity bit first, and the previously selected bit when selecting an additional parity bit second. Fixed and provided to select the best performing bit out of the remaining bits, consider the following in selecting the high performing bit:

(1) Degree of variable node corresponding to codeword bit
(2) Minimum cycle of variable node corresponding to codeword bit
(3) BER performance such as codeword bits

<Embodiment 5>
8A to 8C show a frame structure based on rule 5 according to an embodiment of the present invention.

Referring to FIG. 8A, the codeword includes an information part and a parity part. The length of the information part after shortening is 7 bits, I = {i ₀ , i ₁ ,..., I ₆ }, the length of the parity part is 8, and P = {p ₀ , p ₁ , p ₂ , .., P ₇ }, and a drilling pattern set A = {1, 5, 2, 6, 4, 0, 3, ₇ } indicating the drilling order.

(ここで、Ｎ_puncは穿孔ビットの個数であり、ｓは追加パリティビットが伝送されるフレームの個数であり、

はその関連したフレームで伝送される追加パリティビットの個数である。)である場合、追加パリティビットのグループは、後述するように生成される。 The number of parity bits transmitted in the same frame as the information bits is 5, N _punc = 3, s = 3,

(Where N _punc is the number of puncturing bits, s is the number of frames in which additional parity bits are transmitted,

Is the number of additional parity bits transmitted in the associated frame. ), The group of additional parity bits is generated as described below.

Since N _punc = 3, p ₁ , p ₅ , and p ₂ are punctured, the parity bits transmitted through the same frame as the information bits are p ₀ , p ₃ , p ₄ , p ₆ , and p ₇ .

In mapping each bit to each group in the puncturing order according to rule 5, the first group G (0) = {p ₁ , p ₅ } has the first and second elements 1 of the puncturing pattern as its index value. Are generated by selecting parity bits p ₁ and p ₅ having 5. In the second group, the parity bits p ₂ having a third element 2 of the drilling pattern as the index is selected. Since all the punctured parity bits are selected, the second group is generated by selecting one of the information bits and the non-punctured parity bits. When the first information bit is selected, the second group is G (1) = {p ₂ , i ₀ }. If i ₁ and i ₂ are selected from among information bits and non-punctured parity bits to generate a third group, the third group is G (2) = {i ₁ , i ₂ } . The first group is transmitted through the (k + 2) th frame, the second group is transmitted through the (k + 1) th frame, and the third group is transmitted through the kth frame.

Referring to FIG. 8B, when each bit is mapped to a group in the reverse order of the puncturing pattern, the first group G (0) = {p ₂ , p ₅ }, the second group G (1) = {p ₁ , I ₀ }, the third group G (2) = {i ₁ , i ₂ } is from among the parity bits {p ₁ , p ₅ , p ₂ } punctured in the elements of puncturing pattern set A The bit is selected and generated starting from the last bit. The first group is transmitted through the (k + 2) th frame, the second group is transmitted through the (k + 1) th frame, and the third group is transmitted through the kth frame.

Referring to FIG. 8C, in order to facilitate selection of the parity bits transmitted through each frame, the parity bits are sequentially transmitted in reverse order of the puncturing pattern after replacement. That is, since the puncturing pattern is A = { ₁ , ₅ , ₂ , ₆ , ₄ , ₀ , ₃ , ₇ }, the parity bits are p ₇ , p ₃ , p ₀ , p ₄ , which are the reverse order of the puncturing pattern. The parity bits arranged as p ₆ , p ₂ , p ₅ , and p ₁ and transmitted in the same frame as the information bits are selected sequentially from the arranged parity bits, so p ₇ , p ₃ , p ₀ , p ₄ , and p ₆ . For G _(1), p 1 is selected, one bit is selected from the information bits. For G (2), 2 bits are selected from the information bits according to a greedy algorithm.

  Although the determined groups are transmitted sequentially, the transmission order of the groups can be changed.

<Embodiment 6>
The length of the information part after shortening is 7 bits, I = {i ₀ , i ₁ ,..., I ₆ }, the length of the parity part is 8 bits, and P = {p ₀ , p ₁ , p ₂ ,..., P ₇ }, and a drilling pattern set A = {1, ₅ , ₂ , ₆ , 4, 0, 3, ₇ } indicating the drilling order.

(ここで、Ｎ_puncは穿孔ビットの個数であり、ｓは追加パリティビットが伝送されるフレームの個数であり、

はその関連したフレームで伝送される追加パリティビットの個数である。)である場合、追加パリティビットのグループは、後述するように生成される。 N _punc = 3, s = 3,

(Where N _punc is the number of puncturing bits, s is the number of frames in which additional parity bits are transmitted,

Is the number of additional parity bits transmitted in the associated frame. ), The group of additional parity bits is generated as described below.

Since N _punc = 3, p ₁ , p ₅ , and p ₂ are punctured, the parity bits transmitted through the same frame as the information bits are p ₀ , p ₃ , p ₄ , p ₆ , and p ₇ .

By mapping the remaining parity bits, ie the parity bits to be punctured, into groups in the puncturing order according to rule 5, the first group is G (0) = {p ₁ , p ₅ , p ₂ , i ₀ } , The second group is G (1) = {i ₁ , i ₂ , i ₃ , i ₄ }, and the third group is G (2) = {i ₅ , i ₆ , p ₆ , p ₄ }. It is. When the third group G (2) is generated, the parity bits are arranged as i ₁ , i ₅ , p ₂ , p ₆ , i ₄ , i ₀ , p ₃ , p ₇ according to the puncturing pattern. In which i ₁ , i ₅ , p ₂ are selected for the first group G (0), after which p ₆ , i ₄ are selected for the third group G (2) .

By mapping the punctured parity bits to each group in the reverse order of the puncture order, the first group is G (0) = {p ₂ , p ₅ , p ₁ , i ₀ } and the second group is G (1) = {i ₁ , i ₂ , i ₃ , i ₄ }, and the third group G (2) = {i ₅ , i ₆ , p ₇ , p ₃ }. In the generation of the third group G (2), the parity bits are arranged as i ₇ , i ₃ , p ₀ , p ₄ , i ₆ , i ₂ , p ₅ , p _{1 in} the reverse order of the puncturing pattern, , I ₂ , i ₅ , p ₁ are selected for the first group G (0) and p ₇ , which are the first and second parity bits among the parity bits arranged in the reverse order of the puncturing order. i ₃ is selected for the third group G (2).

  The first group is transmitted through the (k + 2) th frame, the second group is transmitted through the (k + 1) th frame, and the third group is transmitted through the kth frame.

  The determined groups are transmitted sequentially, but the transmission order of the groups can be changed. Also, various methods for selecting information bits can be used in other embodiments of the present invention.

The following is DVB-S2 (Digital Video Broadcasting the 2nd Generation Satellite), DVB-T2, DVB-C2 (Digital Video Broadcasting the 2nd Generation Cable), and additional parity bits when encoding and decoding are performed based on the parity check matrix used in the DVB-NGH system A method of generating the will be described.

In the following description, the coding rate of the parity check matrix is R = _4/9 , the number of information bits is K _ldpc = 7200, the number of codeword bits is N _lpdc = 16200, and the number of parity bits is N Assume that _parity = N _lpdc -K _lpdc = 9000.

As described above, blocks are generated in units of 360 columns for the information portion of the LDPC code. In the parity check matrix, a total of 20 column groups are generated by grouping 7200 columns corresponding to information words in units of 360 columns. The parity part includes 360 elements as shown in Equation (2), and can express Q _ldpc groups indicating parity indexes. When the coding rate is 4/9, Q _ldpc = 25. Furthermore, any one of the perforation patterns in Table 1 can be used.

  For convenience of explanation, the set of indexes including the column group of the information part can be expressed as shown in the following equation (8).

In equation (8), [k / 360] means an integer smaller than k / 360. For example, when k / 360 = 0.2, [0.2] = 0, or when k / 360 = 11.8, [11.8] = 11. N _info represents the number of column groups in the information part. When R = _4/9 , N _info = 20. Further, K _bch represents the number of information bits of the BCH code when the LDPC code and the BCH code are connected and used.

  Hereinafter, the order of generating the optimum additional parity bits according to the length will be described. In the following description, it is assumed that additional parity bits can be selected from the parity bits in reverse order of puncturing.

  When the number of input information words is 7200, the additional parity bits are preferentially selected in the reverse order of puncturing because puncturing and shortening are unnecessary. That is, by selecting an index value in the following order, an information bit and a parity bit corresponding to the index value are selected. In the following description, I (a) represents a set of parity bit indexes as defined in Equation (3), and X (a) represents an information bit index set as defined in Equation (8). Represents. In other words, I (a) means that a parity bit having an element of I (a) is selected as its index, and X (a) is an information bit having an element of X (a) whose index is Means to be selected.

    I (11) → I (7) → I (19) → I (21) → I (0) → I (14) → I (1) → I (23) → I (16) → I (3) → I (12) → I (22) → I (10) → I (24) → I (2) → I (17) → I (5) → I (20) → I (15) → I (8) → I (13) → I (9) → I (18) → I (4) → I (6)

    I (9) → I (26) → I (3) → I (15) → I (30) → I (13) → I (6) → I (19) → I (34) → I (16) → I (1) → I (23) → I (4) → I (17) → I (22) → I (24) → I (7) → I (11) → I (31) → I (10) → I (8) → I (2) → I (35) → I (28) → I (20) → I (18) → I (25) → I (33) → I (0) → I (21) → I (12) → I (5) → I (32) → I (29) → I (14) → I (27)

  If additional parity bits are needed, the bits are selected in the following order:

    I (11) → I (7) → I (19) → I (21) → I (0) → I (14) → I (1) → I (23) → I (16) → I (3) → I (12) → I (22) → I (10) → I (24) → I (2) → I (17) → I (5) → I (20) → I (15) → I (8) → I (13) → I (9) → I (18) → I (4) → I (6) → X (5) → X (6) → X (7) → X (8) → X (9) → X (10) → X (11) → X (12) → X (13) → X (14) → X (15) → X (16) → X (17) → X (18) → X (19) → X (0) → X (1) → X (2) → X (3) → X (4)

  X (4) → X (5) → I (9) → I (26) → X (6) → X (7) → X (8) → I (3) → I (15) → I (30) → I (13) → I (6) → I (19) → I (34) → I (16) → I (1) → I (23) → I (4) → I (17) → I (22) → I (24) → I (7) → I (11) → I (31) → I (10) → I (8) → I (2) → I (35) → I (28) → I (20) → I (18) → I (25) → I (33) → I (0) → I (21) → I (12) → I (5) → I (32) → I (29) → I (14) → I (27)

  Thereafter, when an additional parity bit is further required, it is repeated in the same manner as the transmission order described above.

  As another embodiment, when the number of input information words is 3600, 10 information blocks are shortened and 12 parity blocks are punctured. As a result, the number of blocks that are not punched is 25-12 = 13, and the blocks that are not punched are first selected in the following order.

    I (11) → I (7) → I (19) → I (21) → I (0) → I (14) → I (1) → I (23) → I (16) → I (3) → I (12) → I (22) → I (10)

    I (9) → I (26) → I (3) → I (15) → I (30) → I (13) → I (6) → I (19) → I (34) → I (16) → I (1) → I (23) → I (4) → I (17) → I (22) → I (24) → I (7) → I (11) → I (31) → I (10) → I (8) → I (2) → I (35) → I (28) → I (20) → I (18) → I (25) → I (33) → I (0)

If more parity bits are needed, they are selected in the following order:
X (5) → X (6) → X (7) → X (8) → X (9) → X (19) → X (0) → X (1) → I (11) → I (7) → X (2) → X (3) → I (19) → I (21) → I (0) → I (14) → I (1) → I (23) → I (16) → I (3) → I (12) → I (22) → I (10) → I (24) → I (2) → I (17) → I (5) → I (20) → I (15) → I (8) → I (13) → I (9) → I (18) → I (4) → I (6)

  I (21) → I (12) → I (5) → I (32) → I (29) → I (14) → I (27) → X (4 → X (5 → X (6) → I ( 9) → X (8) → I (26) → I (3) → I (15) → I (30) → I (13) → I (6) → I (19) → X (4) → I ( 34) → I (16) → I (1) → I (23) → I (4) → I (17) → I (22) → I (24) → I (7) → X (5) I (11 ) → I (31) → I (10) → I (8) → X (6) → I (2) → I (35) → I (28) → I (20) → I (18) → I (25 ) → I (33) → I (0) → I (21) → I (12) → I (5) → I (32) → I (29) → I (14) → I (27)

  Thereafter, if additional parity bits are required, the bits are transmitted repeatedly from the codeword bits.

  As can be seen from the above description, the order of selecting the additional parity bits having the optimum performance can be different depending on the input information bits. However, optimal performance and optimal system efficiency can be achieved when bits are selected as described below.

  More specifically, since method 1 does not transmit parity bits in the same frame as information bits, additional parity bits can be selected in the following order.

(1) Parity bits that are not punctured are selected in the order of puncturing patterns or in reverse order.
(2) If additional parity bits are needed, the punctured parity bits are selected in the order of the puncturing pattern or in reverse order.
(3) If additional parity bits are required, the bits are selected from information bits of degree 3.
(4) If additional parity bits are needed, the parity bits are selected in the order of the drilling pattern or in reverse order.
(5) If additional parity bits are required, information bits with degree 12 are selected.
(6) If additional parity bits are needed, the above procedure is repeated from step (1).

  According to another embodiment of the present invention, the additional parity bits can be selected in the following order:

(1) Parity bits that are not punctured are selected in the order of puncturing patterns or in reverse order.
(2) If additional parity bits are needed, the punctured parity bits are selected in the order of the puncturing pattern or in reverse order.
(3) If additional parity bits are required, the bits are selected from information bits of degree 3.
(4) If additional parity bits are needed, information bits with degree 12 are selected.
(5) If additional parity bits are needed, the parity bits are selected in the order of the drilling pattern or in reverse order.
(6) If additional parity bits are needed, the above procedure is repeated from step (1).

  According to another embodiment of the present invention, the additional parity bits can be selected in the following order.

(1) Parity bits that are not punctured are selected in the order of puncturing patterns or in reverse order.
(2) If additional parity bits are needed, the punctured parity bits are selected in the order of the puncturing pattern or in reverse order.
(3) If additional parity bits are needed, the parity bits are selected in the order of the drilling pattern or in reverse order.
(4) If additional parity bits are needed, the bits are selected from information bits of order 12.
(5) If additional parity bits are needed, information bits with degree 2 are selected.
(6) If additional parity bits are needed, the above procedure is repeated from step (1).

  As described above, since the method 2 transmits the parity bits in the same frame as the information word bits, the parity bits that are not punctured are transmitted in the same frame as the information bits.

  Therefore, according to the embodiment of the present invention, the additional parity bits are selected in the following order.

(1) If additional parity bits are required, the punctured parity bits are selected in the order of the puncturing pattern or in reverse order.
(2) If additional parity bits are needed, the bits are selected from information bits of degree 3.
(3) If additional parity bits are needed, the parity bits are selected in the order of the drilling pattern or in reverse order.
(4) If additional parity bits are needed, information bits with degree 12 are selected.
(5) If additional parity bits are required, parity bits that are not punctured are selected in the order of the puncturing pattern or in reverse order.
(6) If additional parity bits are needed, the above procedure is repeated from step (1).

  According to another embodiment of the present invention, the additional parity bits can be selected in the following order.

(1) If additional parity bits are required, the punctured parity bits are selected in the order of the puncturing pattern or in reverse order.
(2) If additional parity bits are needed, the bits are selected from information bits of degree 3.
(3) If additional parity bits are needed, information bits with degree 12 are selected.
(4) If additional parity bits are needed, the parity bits that are punctured and the parity bits that are not punctured are selected in the order of the puncturing pattern or in reverse order.
(5) If additional parity bits are needed, the above procedure is repeated from step (1).

  According to another embodiment of the present invention, the additional parity bits are selected in the following order.

(1) If additional parity bits are required, the punctured parity bits are selected in the order of the puncturing pattern or in reverse order.
(2) If additional parity bits are needed, the parity bits are selected in the order of the drilling pattern or in reverse order.
(3) If additional parity bits are required, the bits are selected from information bits of degree 3.
(4) If additional parity bits are needed, information bits with degree 12 are selected.
(5) If additional parity bits are needed, the above procedure is repeated from step (1).

  The above method has been described based on a code having a coding rate of 1/2 among LDPC codes used in DVB-S2, DVB-T2, DVB-C2, and DVB-NGH systems. The same method can be applied to the coding rate.

  FIG. 9 shows a frame structure of a DVB-T2 / NGH system according to an embodiment of the present invention.

  Referring to FIG. 9, the signaling information word used in the DVB-T2 / NGH system includes a configuration information part and a dynamic information part. This setting information portion includes information that does not change for several frames. The dynamic information portion includes information that changes in each frame. Since the setting information part and the dynamic information part contain information on the data of the current frame, it is important to receive without error. For example, when a Cyclic Redundancy Check (CRC) error occurs, the data information of the corresponding frame may not be received.

  Since the same information is received in several frames in the setting information part, when the received information is stored, the error can be corrected by acquiring the diversity gain using the stored information. However, since the dynamic information portion is not transmitted repeatedly, sufficient diversity gain cannot be obtained, resulting in a significant decrease in error correction capability.

である複数のグループＧ(０)，Ｇ(１)，…，Ｇ(ｓ-１）に分けられてｓ個のフレームを通じて伝送される。図９ではｓ＝３であるが、ｓはランダムに決定できることは明らかである。各グループに属するビットは、同一のフレームを通じて伝送される。規則３及び４は、パリティビットを複数のグループに分離する方法に適用することができる。Ｇ(０)，Ｇ(１)，…，Ｇ(ｓ-１）が図９のフレームに順次にマッピングされるが、グループをフレームにマッピングする方法は多様に変更可能である。 Therefore, as shown in FIG. 9, the additional parity bit is transmitted in a plurality of frames by applying the above-described method 1 to the dynamic information portion. In other words, the additional parity bit is generated after encoding the dynamic information part, and this additional parity bit has the number of elements.

Are divided into a plurality of groups G (0), G (1),..., G (s-1) and transmitted through s frames. In FIG. 9, s = 3, but it is clear that s can be determined randomly. Bits belonging to each group are transmitted through the same frame. Rules 3 and 4 can be applied to the method of separating the parity bits into a plurality of groups. G (0), G (1),..., G (s-1) are sequentially mapped to the frame of FIG. 9, but the method of mapping the group to the frame can be variously changed.

  The occurrence of errors in the signaling information can be detected through a CRC check. If an error is detected through the CRC check, G (0), G (1),..., G (s-1) are received and additionally decode the dynamic information. After performing the decoding operation, the CRC check for signaling is performed once more to determine if there is an error.

  If an error occurs in the additional parity bit of the signaling information part, the CRC check error may continue to occur even if the dynamic information is recovered through additional decoding. To solve these problems, additional CRCs can be used for dynamic information.

  FIG. 10 shows a frame structure in which an additional CRC is used for dynamic information. In particular, FIG. 10 illustrates a frame structure of a DVB-T2 / NGH system according to another embodiment of the present invention.

  When dynamic information is transmitted in the (k + 3) th frame, the CRC for dynamic information can be transmitted through any one of frames in which additional parity bits are transmitted. As shown in FIG. 10, the CRC is transmitted in the (k + 2) th frame. When dynamic information is encoded by the above method, the CRC may or may not be included in the information word.

  In the DVB-T2 / NGH system, signaling information including configuration information, dynamic information, extension part, CRC, and padding bits is encoded as an information word.

  According to an embodiment of the present invention, when information is transmitted as shown in FIGS. 9 and 10, the transmitter performs additional coding on the dynamic information, and CRC error occurs on the signaling information. If so, the receiver performs an additional decoding process for the signaling information. Also, if the puncturing and shortening pattern for encoding dynamic information is different from the puncturing and shortening pattern for signaling, an additional module is required for encoding and decoding dynamic information.

  Using a frame structure as shown in FIGS. 9 and 10, encoding and decoding are performed twice for signaling information. That is, signaling is divided into two types of different information. One is setting (conf) information that does not change from frame to frame, and the other is dynamic (dyn) information that changes from frame to frame. These two pieces of information are input and encoded as one information word. Among them, only dyn information is encoded separately, and the parity bit is transmitted in the previous frame. Thus, first, conf and dyn are input and encoded as information words, and secondly, dyn is input and encoded. However, using Method 2, the encoding can be performed only once and no additional puncturing and shortening patterns are required, so the additional module should be minimized in the encoding and decoding process. Can do.

  FIG. 11 shows a frame structure of a DVB-T2 / NGH system according to another embodiment of the present invention. In particular, FIG. 11 shows method 2 as described above applied to the DVB-T2 / NGH system.

  The setting information and dynamic information are received and LDPC encoded. In general, since signaling is variable, shortening and puncturing are performed to adaptively encode according to variable length.

  In the NGH system, since the setting information and dynamic information are each encoded, the L1 signaling in FIG. 11 means all types of L1 signaling information instead of being limited to the setting and dynamic information.

である追加パリティビットのグループＧ(０)，Ｇ(１)、Ｇ(２）は、各々(ｋ＋２)番目のフレーム、(ｋ＋１)番目のフレーム、ｋ番目のフレームで伝送される。 Parity bits that are not punctured are transmitted in the (k + 3) th frame, which is the same frame as the signaling bits in FIG. The number of elements calculated by rule 5 is

The additional parity bit groups G (0), G (1), and G (2) are transmitted in the (k + 2) th frame, the (k + 1) th frame, and the kth frame, respectively.

  Although it is assumed in FIG. 11 that the number of frames in which the additional parity bits are transmitted is 3, other frame numbers may be used. Further, the positions of the groups G (0), G (1), and G (2) of additional parity bits can be changed. That is, the additional parity bits may be transmitted in P1 / P2 symbols or may be transmitted in an auxiliary stream. Further, the additional parity bit can be transmitted using a general data stream.

  As described above, the additional parity bit is transmitted through the (k + 2) -th frame, the (k + 1) -th frame, and the k-th frame, that is, the sub-sequence frame, but is transmitted through s previous frames. can do.

  22A and 22B illustrate various frame configurations according to different embodiments of the present invention. In particular, FIGS. 22A and 22B illustrate a frame configuration in which additional parity bits are transmitted in s previous frames.

  FIG. 22A shows additional parity bits transmitted through concatenated previous frames. For example, in a DVB-NGH system, an NGH frame is transmitted using a DVB-T2 FET (Future Extension Frame). Accordingly, the various embodiments of the present invention are not limited to the additional parity bits being transmitted in s concatenated frames, but are applied to transmission through s frames before the frame transmitting the information bits. obtain.

  FIG. 22B shows that additional parity bits are transmitted in other RF bands. That is, according to the embodiment of the present invention, the additional parity bit is not limited to a frame transmitted on the same RF channel.

  Signaling used in the DVB-T2 system is classified into two types. One is L1 pre-signaling, and the other is an L1 post part including a setting part, a dynamic part, and an extension part. Method 2 has been described based on L1 post-signaling of T2 type signaling in FIG. 2, but can be applied to L1 pre-signaling of other types, for example DVB-NGH.

  As in method 2, after encoding signaling information, parity bits that are not punctured are transmitted in the same frame as the information bits, and additional parity bits including information bits and parity bits are transmitted through the previous frame. For additional parity bits, the punctured parity bits are first selected, and these bits are selected in the order of the puncturing pattern or in reverse order.

The (N _ldpc -K _ldpc ) parity bits are divided into Q _ldpc groups, and the j-th parity group P _j can be expressed as shown in Equation (9).

According to the following formula (10), Q _ldpc can be calculated based on M, N _ldpc , and K _ldpc as shown in FIG.

In equation (10), the parity bits are divided into Q _ldpc groups, each group including M bits.

For a predetermined number of puncturing bits N _punc , the parity bits to be punctured can be calculated as in Steps 1 to 3 below.

は、ａを超えない最大整数を意味する。例えば、

であり、

である。 Step 1: The number N _{punc_group} of groups in which all parity bits are punctured is obtained by the following equation (11). Where operator

Means the largest integer not exceeding a. For example,

And

It is.

に対して、このグループのすべてのパリティビットは穿孔される。パリティグループのインデックスを表すπ_p(ｊ)は、例えば＜表１＞に定義されたように穿孔される順序を意味する。例えば、ＢＰＳＫ変調において、π_p(０)は６であるため、パリティビットグループ内のパリティビット

はまず穿孔される。 Step 2: N _{punc_group} parity bit groups

In contrast, all parity bits in this group are punctured. Π _p (j) representing the index of the parity group means the order of punching as defined in <Table 1>, for example. For example, in BPSK modulation, since π _p (0) is 6, parity bits in the parity bit group

Is first drilled.

に対して、(Ｎ_punc-Ｍ×Ｎ_{punc_group})個のビットは、上記グループの最初のパリティビットから穿孔される。穿孔されないパリティビットは、情報ビットと同一のフレームで伝送される。 Step 3: Group

On the other hand, (N _punc −M × N _{punc_group} ) bits are punctured from the first parity bit of the group. Parity bits that are not punctured are transmitted in the same frame as the information bits.

<Embodiment 7>
The first group of additional parity bits G (0) is calculated as follows: For convenience of explanation, assume that the method is performed from step 4 below after performing steps 1 to 3 described above.

  Step 4: The number of parity bit groups from which all elements are selected to select additional parity bits can be calculated using equation (12).

は、最初の追加パリティビットの個数を表す。 In equation (12):

Represents the number of first additional parity bits.

個のパリティビットグループは

であり、グループのすべてのパリティビットは、最初の追加パリティビットのグループＧ(０)に含まれ、情報ビットが伝送されるフレームに先立つフレームを通じて伝送される。この先行するフレームは、図２２に関連して説明したように、他のＲＦチャンネルにも適用できる。 Step 5:

Group of parity bits

And all the parity bits of the group are included in the first additional parity bit group G (0) and are transmitted through a frame preceding the frame in which the information bits are transmitted. This preceding frame can also be applied to other RF channels as described in connection with FIG.

に対して、

個のパリティビットは、上記グループ内の最初のパリティビットを始めとして、最初のパリティビットのグループＧ(０)に含まれる。 Step 6: Group

Against

The number of parity bits is included in the first parity bit group G (0), including the first parity bit in the group.

の順序でパリティビットのグループ

単位で配列される。また、図１２Ｂに示したように、Ｇ(０)に対して選択されるパリティビットは、パリティビットのインデックス順にビット単位で配列され得る。 Various ways of determining the order of the bits in the first group of additional parity bits G (0) are possible. For example, as shown in FIGS. 12A and 12C, a bit is a group of parity bits.

Group of parity bits in order

Arranged in units. Also, as shown in FIG. 12B, the parity bits selected for G (0) may be arranged in bit units in the order of parity bit index.

において、最初の追加パリティビットのグループＧ(０)に含まれていないパリティビットの個数は、式(１３)を用いて計算することができる。ｘ及びｙの定義は、図１２Ａ乃至図１２Ｃに示す。 Step 7: Group

, The number of parity bits not included in the first additional parity bit group G (0) can be calculated using Equation (13). The definitions of x and y are shown in FIGS. 12A to 12C.

の

番目のビットから計算することができる。“ａ番目のビット”との用語は、グループ

の第１のビットが０番目のビットとして定義される場合にａ番目に位置するビットを意味する。さらに、ｍｉｎ(ａ，ｂ）は、最小値であるａ及びｂのうち一つを選択する関数を表す。例えば、ａ≦ｂの場合にｍｉｎ(ａ，ｂ)＝ａ、そして、ａ＞ｂの場合にはｍｉｎ(ａ，ｂ)＝ｂである。 Therefore, the second group of additional parity bits G (1)

of

Can be calculated from the second bit. The term “ath bit” is a group

Is defined as the 0th bit, it means the bit located at the ath. Further, min (a, b) represents a function for selecting one of a and b which are minimum values. For example, min (a, b) = a when a ≦ b, and min (a, b) = b when a> b.

である場合、追加パリティビットを選択するためにすべてのエレメントが選択されるパリティビットグループの個数は、以下の式(１４)を用いて計算される。 Step 8:

, The number of parity bit groups from which all elements are selected to select additional parity bits is calculated using Equation (14) below.

のすべてのパリティビットは、２番目の追加パリティビットのグループに含まれる。 Step 9: Group

Are included in the second group of additional parity bits.

において、

個のパリティビットは、２番目の追加パリティビットとして生成される。 Step 10: Group

In

The parity bits are generated as the second additional parity bit.

において、２番目の追加パリティビットのグループＧ(１)に含まれていないパリティビットの個数ｙは、式(１５)を用いて計算することができる。 Step 11: Group

The number y of parity bits not included in the second group of additional parity bits G (1) can be calculated using Equation (15).

のｘ個のビットを始めとして、三番目の追加パリティビットのグループＧ(２)に含まれることができる。 Thus y bits are group

And the third additional parity bit group G (2), starting with x bits.

である場合、３番目の追加パリティビットを選択するためにエレメントがすべて選択されるパリティビットグループの個数は、式(１６)により計算できる。 Step 12:

In this case, the number of parity bit groups in which all elements are selected to select the third additional parity bit can be calculated by Equation (16).

，

，…，

のすべてのパリティビットは、３番目の追加パリティビットのグループに含まれる。 Step 13: Group

,

, ...,

Are included in the third group of additional parity bits.

において、

個のパリティビットは、３番目の追加パリティビットとして生成される。 Step 14: Group

In

The parity bits are generated as the third additional parity bit.

  The method of determining the bit order of the second additional parity bit group G (1) is the same as the method of determining the bit order of the first additional parity bit group G (0).

<Eighth embodiment>
Hereinafter, a method of selecting additional parity bits in the reverse order of the puncturing pattern will be described with reference to FIGS. 13A to 13C.

  As described above, the method for obtaining the parity bits transmitted in the same frame as the information bits corresponds to steps 1 to 3.

  The first additional parity bit group G (0) is calculated in the following manner.

のグループＧ(０)に対して選択されるビットの個数ｙは、式(１７)を用いて計算することができる。 Step 4: Group

The number y of bits selected for the group G (0) can be calculated using equation (17).

の最初のビットから最初の追加パリティビットとして選択される。 Step 5: y bits are group

Are selected as the first additional parity bit.

の最後のパリティビットから穿孔され、穿孔されないビットが情報ビットと同一のフレームを通じて伝送される場合、ｙ個のビットは、ステップ５でグループ

の最後のパリティビットから最初の追加パリティビットとして選択される。 (N _ldpc -M × N _{punc_group} ) bits are grouped in step 3

If the bits that are punctured from the last parity bit and are not punctured are transmitted through the same frame as the information bits, y bits are grouped in step 5

Are selected as the first additional parity bit from the last parity bit.

がｙより大きい場合、次のステップ６〜８が遂行される。

If is greater than y, the following steps 6-8 are performed.

  Step 6: The number of parity bit groups in which all bits are transmitted is calculated using equation (18).

個のパリティビットグループ

，

，…，

のすべてのパリティビットは、最初の追加パリティビットのグループＧ(０)に含まれ、情報ビットが伝送されるフレームより先行するフレームで伝送される。 Step 7:

Parity bit groups

,

, ...,

Are included in the first additional parity bit group G (0) and are transmitted in a frame preceding the frame in which the information bits are transmitted.

個のパリティビットは、グループ

の最初のパリティビットから、最初の追加パリティビットのグループＧ(０)に含まれる。 Step 8:

Parity bits are group

To the first additional parity bit group G (0).

の順序でパリティビットのグループ

単位で配列される。また、図１３Ｂに示したように、追加パリティビットとして選択されたパリティビットは、パリティビットのインデックス順にビット単位で配列され得る。 Various ways of determining the order of the bits in the first group of additional parity bits G (0) are possible. For example, as shown in FIGS. 13A and 13C, a bit is a group of parity bits.

Group of parity bits in order

Arranged in units. Also, as shown in FIG. 13B, the parity bits selected as the additional parity bits may be arranged in bit units in the order of parity bit index.

  The second additional parity bit group G (1) is generated by steps 9-12.

のグループＧ(１)に対して選択されるビットの個数ｙは、式(１９)によって計算される。 Step 9: Group

The number y of bits selected for the group G (1) is calculated by the equation (19).

の最初のビットから選択される。 Step 10: y bits are groups

Selected from the first bit of.

がｙより大きい場合に、次のようなプロセスが遂行される。

When is greater than y, the following process is performed.

  Step 11: The number of parity bit groups in which all bits are transmitted is calculated using Equation (20).

個のパリティビットグループ

，

，…，

のすべてのパリティビットは、２番目の追加パリティビットのグループＧ(１)に含まれ、情報ビットが伝送されるフレームを先行するフレームを通じて伝送される。 Step 12:

Parity bit groups

,

, ...,

Are included in the second group of additional parity bits G (1) and are transmitted through the frame preceding the frame in which the information bits are transmitted.

個のパリティビットは、グループ

の最初のパリティビットから、２番目の追加パリティビットのグループＧ(１)に含まれる。 Step 13:

Parity bits are group

To the second additional parity bit group G (1).

  The method of determining the bit order of the second additional parity bit group G (1) is the same as the method of determining the bit order of the first additional parity bit group G (1).

<Ninth Embodiment>
Hereinafter, a method of efficiently calculating additional parity bits by interleaving parity bits will be described with reference to FIGS. 14A to 14D.

は、式(２１)によってインタリービングされる。 Parity bits acquired by LDPC encoding

Are interleaved by equation (21).

The parity bit group is group-interleaved based on π _p (j) and can be expressed as shown in Equation (22).

Once interleaved by Equation (21), LDPC codeword constituted as shown in FIG. 14A, as shown in FIG. 14B, a plurality of parity bit groups _{P a (0 ≦ a <Q} ldpc) arranged in the unit Is done.

のビットと同一である。穿孔される順序を示す値であるπ_p(ｊ)は、＜表１＞に示した０≦ａ＜Ｑ_ldpcに対する穿孔パターンを意味する。 Group interleaving or group-based interleaving means that the bits in the group are interleaved identically, and the bits in group Z _i are

Is the same bit. Π _p (j) which is a value indicating the order of drilling means a drilling pattern for 0 ≦ a <Q _ldpc shown in Table 1.

  When interleaved according to Equation (22), the LDPC codeword as shown in FIG. 14B has an arrangement in which a plurality of groups of parity bits are arranged in reverse order of the puncturing pattern, as shown in FIG. 14C.

  Hereinafter, a method for calculating the parity bits transmitted in the same frame as the information bits will be described.

Step 1: The number of parity bit groups N _{tx_group} in which all parity bits are transmitted can be calculated based on the number of parity bits punctured according to Equation (23).

内のすべてのパリティビットが伝送される。 Step 2: N _{tx_group} parity bit groups

All parity bits are transmitted.

の最初のパリティビットから、これらの情報ビットと同一のフレームを通じて伝送される。 Step 3: (N _tx -M × N _{tx_group} ) bits are group

Are transmitted through the same frame as these information bits.

  The first additional parity bit is calculated using steps 4-8.

内の部ループＧ(０)に対して選択されるビットの個数ｙは、式(２４)によって計算できる。 Step 4: Group

The number y of bits selected for the inner loop G (0) can be calculated by equation (24).

の最初のビットから最初の追加パリティビットとして選択される。 Step 5: y bits are group

Are selected as the first additional parity bit.

がｙより大きい場合には、ステップ６及び７が遂行される。

If is greater than y, steps 6 and 7 are performed.

  Step 6: The number of groups in which all bits are transmitted is calculated according to equation (25).

個のパリティビットグループ

，…，

に属するすべてのパリティビットは、最初の追加パリティビットらグループＧ(０)に含まれ、情報ビットが伝送されるフレームに先立つフレームで伝送される。 Step 7:

Parity bit groups

, ...,

All the parity bits belonging to are included in the group G (0) from the first additional parity bit, and are transmitted in a frame preceding the frame in which the information bits are transmitted.

個のパリティビットは、グループ

の最初のパリティビットから最初の追加パリティビットのグループＧ(０)に含まれる。 Step 8:

Parity bits are group

From the first parity bit to the first additional parity bit group G (0).

  The group of additional parity bits is configured as shown in FIG. 14D.

  The second additional parity bit group G (1) is generated in steps 9-13.

のグループＧ(１)に対して選択されるビットの個数ｙは、式(２６)を用いて計算することができる。 Step 9: Group

The number y of bits selected for the group G (1) can be calculated using equation (26).

の最初のビットから選択される。 Step 10: y bits are groups

Selected from the first bit of.

がｙより大きい場合には、ステップ１１乃至１３が遂行される。

If is greater than y, steps 11-13 are performed.

  Step 11: The number of groups in which all bits are transmitted is calculated according to equation (27).

個のパリティビットグループ

，

，…，

に属するすべてのパリティビットは、２番目の追加パリティビットのグループＧ(１)に含まれ、情報ビットが伝送されるフレームに先行するフレームで伝送される。 Step 12:

Parity bit groups

,

, ...,

Are included in the second additional parity bit group G (1) and are transmitted in a frame preceding the frame in which the information bits are transmitted.

個のパリティビットは、グループ

の最初のパリティビットを始めとして、２番目の追加パリティビットのグループＧ(１)に含まれる。 Step 13:

Parity bits are group

And the second additional parity bit group G (1).

  The group interleaving of Expression (22) can be expressed as Expression (28).

として表される。 In this case, the parity bit is

Represented as:

及び

に基づき、情報ビットと同一のフレームで伝送されるパリティビットの個数を示す、式(２３)で計算される値Ｎ_txに従って選択され得る。 Therefore, even if the additional parity bit is not used, the selected parity bit is the additional parity bit.

as well as

Based on the value N _tx calculated by Equation (23) indicating the number of parity bits transmitted in the same frame as the information bits.

、最初の追加パリティビットのグループＧ(０)、及び２番目の追加パリティビットのグループＧ(１)を表す。 Equation (29) is a group of parity bits transmitted in the same frame as the information bits.

, The first additional parity bit group G (0) and the second additional parity bit group G (1).

がＮ_puncより大きい場合、Ｎ_punc個のパリティビットは、実施形態７及び８により選択される。Ｎ_puncを超えることが要求される追加パリティビットは、符号語から選択され、最も簡単な方法は、情報語、この情報語と同一のフレームで伝送されるパリティビット、及び選択された追加パリティビットを、図２３に簡単に示すように、順次に反復して選択する。 Total number of additional parity bits

If N _{punc is} greater than N _punc , N _punc parity bits are selected according to embodiments 7 and 8. The additional parity bits required to exceed N _punc are selected from the code word, the simplest method being the information word, the parity bit transmitted in the same frame as this information word, and the selected additional parity bit Are selected sequentially and repeatedly as shown in FIG.

はＮ_puncより大きい。 <Embodiment 10>
A method for selecting additional parity bits in the reverse order of the puncturing pattern will be described below. Where the total number of additional parity bits

Is greater than N _punc .

  The method for calculating the parity bits transmitted in the same frame as the information bits corresponds to steps 1 to 3 as described above.

  The first group of additional parity bits G (0) is calculated in step 4.

である場合、Ｎ_punc個のビットは、グループＧ(０)に対して選択され、

個のビットは、グループＧ(０)に対して符号語ビットから選択される。簡単な方法では、図２３に示すように、符号語ビット及び追加パリティビットを順次に反復して選択することである。 Step 4:

N _punc bits are selected for group G (0),

The bits are selected from codeword bits for group G (0). In a simple method, as shown in FIG. 23, the code word bits and the additional parity bits are sequentially selected repeatedly.

である場合、実施形態８のステップ４〜８は同一の方式で遂行される。

If this is the case, steps 4 to 8 of the eighth embodiment are performed in the same manner.

  The second additional parity bit group G (1) is generated by the following method.

である場合、Ｇ(１)は、符号語ビットから選択される。最も簡単な方法では、以前に伝送したビットを順次に選択することである。 Step 9: In step 4

Then G (1) is selected from the codeword bits. The simplest method is to sequentially select previously transmitted bits.

及び

である場合、Ｇ(１)は、符号語ビットから選択される。簡単な方法では、図２３に示したように、情報ビット、パリティビット、及び追加パリティビットを順次に反復して選択することである。

as well as

Then G (1) is selected from the codeword bits. In a simple method, as shown in FIG. 23, an information bit, a parity bit, and an additional parity bit are sequentially selected repeatedly.

である場合、実施形態８のステップ９〜１３は、同一の方式で遂行される。

If so, Steps 9 to 13 of Embodiment 8 are performed in the same manner.

  FIG. 15 is a block diagram illustrating a transmission / reception apparatus according to an embodiment of the present invention.

  Referring to FIG. 15, the transmitter 1500 includes an encoder 1502, a modulator 1504, and a frame builder 1506. The message u is encoded by the encoder 1502, modulated by the modulator 1504, and a frame is composed by the frame composer 1506, and then transmitted through the channel. The transmitted signal is received by a receiver 1510 including a frame de-framer 1516, a demodulator 1514, and a decoder 1512. The received signal r is deconstructed by the frame deconstructor 1516, and the signal y is input to the demodulator 1514. The decoder 1512 calculates an estimated value of the message from the signal z demodulated by the demodulator 1514.

  The encoder 1502 generates parity bits by performing puncturing and shortening according to the message size in a predetermined manner.

  FIG. 16 is a block diagram illustrating a transmission apparatus using a shortened LDPC code according to an embodiment of the present invention.

  Referring to FIG. 16, the transmission apparatus includes an encoder 1602, a control unit 1604, a puncturer 1606, an additional parity bit group generator 1608, and a frame composer 1610. In some cases, the transmission device may include a shortening application unit 1600.

  The control unit 1604 determines the number of bits to be shortened by the shortening application unit 1600 according to the length of the information word. The shortening application unit 1600 inserts a bit having a value of 0 at a position corresponding to the shortened bit, or removes a column corresponding to the shortened bit from the parity check matrix of the given LDPC code. The method for determining a shortened pattern uses a shortened pattern stored in a memory, generates a shortened pattern using a sequence generator (not shown), or a parity check matrix and a given information word length. For obtaining a shortened pattern using a density evolution analysis algorithm.

  The LDPC encoder 1602 performs encoding based on the LDPC code shortened by the control unit 1604 and the shortening application unit 1600. Also, puncturing is applied to the LDPC codeword generated by the puncturer 1606 when necessary. The number and position of bits that the punch 1606 must punch is determined by the controller 1604 according to the drilling pattern. That is, the control unit 1604 selects bits to be punched according to the punching order in order to know the punching order or punching pattern. The drilling pattern can be stored in memory or generated using a sequence generator (not shown).

  The additional parity bit group generator 1608 receives the output data of the control unit 1604 and the encoder 1602 and the data of the punch 1606, and generates an additional parity bit group according to the rules described above.

  The frame composer 1610 generates a frame corresponding to the methods 1 and 2 described above.

  FIG. 17 is a block diagram illustrating a receiving apparatus using an LDPC code to which an additional parity bit group is applied according to an embodiment of the present invention. In particular, in the embodiment of the receiving apparatus shown in FIG. 17, a signal transmitted from a communication system using an additional parity bit group is received, and information on additional parity bits constituting the additional parity bit group is received from the received signal. In the case of acquisition, data desired by the user is restored from the received signal.

  Referring to FIG. 17, the receiving apparatus includes a control unit 1700, a shortening / puncturing processor 1702, a demodulator 1704, an additional parity bit group processor 1706, and a decoder 1708. The demodulator 1704 receives and demodulates the LDPC code, reconstructs the frame by the control unit 1700, and estimates the input value of the LDPC encoder in FIG. 16 based on the received signal. Demodulator 1704 transmits the demodulated signal to shortening / puncturing processor 1702, decoder 1708, and additional parity bit group processor 1706.

  Under the control of the control unit 1700, the shortening / puncturing processor 1702 determines information on the shortened and punched bits of the LDPC code based on the signal demodulated by the demodulator 1704, and the position information of the shortened and punched bits. Is transmitted to the decoder 1708.

  The decoder 1708 recovers the user's desired data from the received signal using the output value of the demodulator 1704 and the information length and position information of the shortened and punctured code received from the shorten / puncture processor 1702. The decoder 1708 receives additional parity bit position information and a demodulated value from the additional parity bit group processor 1706 and performs decoding.

  The additional parity bit group processor 1706 processes the position information of the additional parity bit and the demodulated data under the control of the control unit 1700, and transmits the processed data to the decoder 1708. The processing of demodulated data has various meanings. For example, if the same bit is received several times, the demodulated values are added.

  FIG. 18 is a block diagram illustrating a transmission apparatus using a shortened LDPC code according to an embodiment of the present invention.

  Referring to FIG. 18, the transmission apparatus includes an encoder 1802, a control unit 1804, a puncturer 1806, an additional parity bit group generator 1808, a frame composer 1810, and a parity interleaver 1812. In some cases, the transmission apparatus may include a shortening application unit 1800.

  The control unit 1804 determines the number of bits that the shortening application unit 1800 shortens according to the length of the information word. The shortening application unit 1800 inserts a bit having a value of 0 at a position corresponding to the shortened bit, or removes a column corresponding to the shortened bit from the parity check matrix of the given LDPC code. The method for determining a shortened pattern uses a shortened pattern stored in a memory, generates a shortened pattern using a sequence generator (not shown), or a parity check matrix and a given information word length. For obtaining a shortened pattern using a density evolution analysis algorithm.

  The encoder 1802 performs encoding based on the LDPC code shortened by the control unit 1804 and the shortening application unit 1800. Further, the output value of the encoder 1802 is parity interleaved by the parity interleaver 1812 in units of groups or bits as in the ninth embodiment.

  As described above, the parity interleaver 1812 performs interleaving using a puncturing pattern under the control of the control unit 1808. Also, puncturing is applied to the LDPC codeword generated by the puncturer 1806 when necessary. The number and position of bits that the punch 1806 must punch is determined by the controller 1604 according to the drilling pattern. That is, the control unit 1804 selects bits to be punched according to the punching order in order to know the punching pattern (the punching order). The drilling pattern can be stored in memory or generated using a sequence generator (not shown).

  The additional parity bit group generator 1808 receives the output data of the control unit 1804 and the encoder 1802, and the data of the punch 1806, and generates an additional parity bit group according to the rules described above.

  The frame composer 1810 generates a frame corresponding to the methods 1 and 2 described above.

  FIG. 19 is a block diagram illustrating a receiving apparatus using an LDPC code to which an additional parity bit group is applied according to an embodiment of the present invention. In the embodiment of the receiving apparatus shown in FIG. 19, when a signal transmitted from a communication system using an additional parity bit group is received and information on additional parity bits constituting the additional parity bit group is acquired from the received signal, reception is performed. The data desired by the user is restored from the generated signal.

  Referring to FIG. 19, the receiving apparatus includes a control unit 1900, a shortening / puncturing processor 1902, a demodulator 1904, an additional parity bit group processor 1906, a decoder 1908, and a parity deinterleaver 1910. The demodulator 1904 receives and demodulates the LDPC code, and transmits the demodulated signal to the shortening / puncturing processor 1902, the decoder 1908, and the additional parity bit group processor 1906.

  Under the control of the control unit 1900, the shortening / puncturing processor 1902 obtains information regarding the shortened and punched bits of the LDPC code from the signal demodulated by the demodulator 1904, and decodes the position information of the shortened and punched bits. 1908.

  The parity deinterleaver 1910 corresponding to the parity interleaver 1812 shown in FIG. 18 uses the output value of the demodulator 1904, the length of the shortened and punctured code received from the shortening / puncturing processor 1902, and the position information of the corresponding bit. Parity bits are reconstructed to perform parity deinterleaving.

  The decoder 1908 receives the data desired by the user from the output value of the parity deinterleaver 1910, the length and length information of the shortened and punctured code received from the shortening / puncturing processor 1902 and the position information of the corresponding bit. To restore. The decoder 1908 receives the position information and the demodulated value of the additional parity bit from the additional parity bit group processor 1906 and performs decoding.

  Under the control of the control unit 1900, the additional parity bit group processor 1906 processes the position information of the additional parity bit and the demodulated data, and transmits the processed information to the decoder 1908. The processing of demodulated data has various meanings. The demodulated values can be added if the same bit is received several times.

  FIG. 20 is a flowchart illustrating a transmission method according to an embodiment of the present invention.

  Referring to FIG. 20, in step 2000, the controller 1604 (or 1804) determines the number of bits for punching and shortening, the number of frames for transmitting parity bits, and the number of frames for each frame according to the method and rule described above. Determine the number of bits and groups to be transmitted.

  In step 2002, the shortening application unit 1600 (or 1800) processes the shortening when necessary. In step 2004, the encoder 1602 (or 1802) performs LDPC encoding using the determined parameters. In step 2006, punch 1606 (or 1806) shortens and punches the encoded bits. In step 2008, the additional parity bit group generator 1608 (or 1808) generates a plurality of additional parity bit groups according to rules 3 to 5 using the codeword bits and the parity bits. Step 2008 may include a parity interleaving process. In step 2010, the frame builder 1610 (or 1810) transmits the codeword and the additional parity bit group through the plurality of frames according to various methods according to the embodiment of the present invention described above.

  FIG. 21 is a flowchart illustrating a receiving operation of the receiving device according to the embodiment of the present invention.

  Referring to FIG. 21, the receiving apparatus receives a code in step 2100. In step 2102, the demodulator 1704 (or 1904) demodulates the received signal.

  Thereafter, in step 2104, shortening / puncturing processor 1702 (or 1902) performs shortening and drilling on the demodulated signal.

  If there are no shortened / punctured bits, the decoder 1708 (or 1908) skips step 2106 and performs the encoding at step 2108. However, if a shortened / punctured bit is present, the shorten / punctured processor 1702 (or 1902) transmits the location information of the shortened and punctured bit to the decoder 1708 (or 1908) at step 2106 to add an additional parity bit group. The processor 1706 (or 1906) transmits the position information of the additional parity bit to the decoder 1708 (or 1908).

  In step 2108, the decoder 1708 (or 1908) considers the probability that the shortened bit value is 0 based on the position information of the shortened and punctured bits, and the punctured bits are deleted. LDPC decoding is performed after determining that the bit is a bit.

  Although the present invention has been described in connection with specific embodiments, the present invention has been described in detail without departing from the scope and spirit of the invention which is defined based on the description of the claims and equivalents thereof. It will be apparent to those skilled in the art that various changes in the details can be made.

1500 Transmitter 1502, 1602, 1802 Encoder 1504 Modulator 1506, 1810 Frame composer 1510 Receiver 1512, 1708 Decoder 1514, 1704, 1904 Demodulator 15161908 Frame inverse composer 1604, 1700, 1804, 1900 Controller 1606 Punch 1608 1808 Additional parity bit group generator 1610 Frame composer 1702, 1902 Shortening / punching processor 1706 Additional parity bit group processor 1812, 1910 Parity interleaver

Claims (14)

A method for transmitting encoded data, comprising:
Generating parity bits for the information word;
Encoding an information word using the generated parity bit to generate a code word;
Puncturing a portion of the parity bits of the codeword;
Transmitting a frame containing the punctured codeword;
Generating additional parity bits for acquisition of the information word and transmitting them through one or more other frames;
The step of drilling comprises drilling with a specific drilling pattern;
The additional parity bits are generated using the punctured bits ;
The method, wherein the additional parity bit is selected based on a drilling order of the particular drilling pattern . The method according to claim 1, wherein the other frame is a previous frame of a frame including the punctured codeword. When all the punctured bits are selected as the additional parity bits, all or a part of information bits or all or a part of parity bits that are not punctured are selected as the additional parity bits. The method according to 1. The method of claim 1, wherein the additional parity bit is transmitted through a data stream or auxiliary stream or preamble symbol or other frequency (RF). An apparatus for transmitting encoded data, comprising:
An encoder that generates parity bits for an information word and encodes the information word to generate a code word;
A puncturing unit that punctures a part of the parity bits of the codeword encoded by the encoder;
A frame composer that constitutes a frame including the punctured codeword and one or more other frames including additional parity bits for obtaining the information word ;
The punching unit punches a part of the parity bit by a specific punching pattern,
Further seen including a control unit used for the drilling bit as the additional parity bits,
The apparatus, wherein the additional parity bit is selected based on a drilling order of the specific drilling pattern . 6. The apparatus of claim 5 , wherein the other frame is a previous frame of a frame including the punctured bits. The control unit selects all or a part of information bits or all or a part of parity bits that are not punctured as the additional parity bits when all the punctured bits are selected as the additional parity bits. 6. A device according to claim 5 , characterized in that The apparatus of claim 5 , wherein the additional parity bit is transmitted through a data stream or an auxiliary stream, a preamble symbol, or other frequency (RF). A method for receiving encoded data, comprising:
Receiving a plurality of frames;
Decoding received frame data to obtain an information word,
Of the plurality of frames, one frame includes a punctured codeword;
One or more other frames include additional parity bits for the acquisition of the information word ;
The parity bits of the punctured codeword are parity bits generated by puncturing according to a specific puncturing pattern;
The perforated bits are found used as the additional parity bits,
The method, wherein the additional parity bit is selected based on a drilling order of the specific drilling pattern . The method according to claim 9 , wherein the other frame is a previous frame of a frame including the punctured codeword. If the perforated bits are all selected as the additional parity bits, wherein all or part of the information bits, or all or part of the parity bits that are not perforated, characterized in that it is selected as the additional parity bits Item 10. The method according to Item 9 . An apparatus for receiving encoded data, comprising:
A demodulator that receives and demodulates multiple frames;
A decoder for decoding received frame data to obtain an information word,
Of the plurality of frames, one frame includes a punctured codeword ;
One or more other frames include additional parity bits for the acquisition of the information word;
The parity bits of the punctured codeword are parity bits generated by puncturing according to a specific puncturing pattern;
Further seen including a control unit to determine that the perforated bit is used as the additional parity bits,
The apparatus, wherein the additional parity bit is selected based on a drilling order of the specific drilling pattern . The apparatus according to claim 12 , wherein the other frame is a previous frame of a frame including the punctured codeword. When all the punctured bits are selected as the additional parity bits, the control unit selects all or a part of the information bits or all or a part of the parity bits that are not punctured as the additional parity bits. The apparatus according to claim 12 , wherein a determination is made.

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