JP6629073B2 - Encoding device, semiconductor chip, and encoding program - Google Patents

Description

Embodiments of the present invention, encoding apparatus for concatenated coding data such as video and audio, a semiconductor chip mounted on the encoder, and relates to a coding program executed by the encoding apparatus.

  ISDB-T (Integrated Services Digital Broadcasting-Terrestrial), which is a terrestrial digital broadcasting system in Japan, realizes Hi-Vision (registered trademark) broadcasting (or multiple standard definition broadcasting) for fixed reception. In the next-generation terrestrial digital broadcasting system, it is required to provide a service with a larger amount of information by 3D high-definition broadcasting or super high-definition having 16 times the resolution of high-definition instead of conventional high-definition. Therefore, reducing the required C / N (Carrier to Noise) by increasing the data capacity and using an error correction technique has been an issue.

  In recent years, LDPC codes (Low Density Parity Check Codes) have been adopted in many transmission systems as high-performance error correction codes approaching the Shannon limit. It is also known that the error correction capability is improved by using a concatenated code combining an LDPC code and a BCH code (Bose Chaudhuri Hocquenghem Code) (for example, see Non-Patent Document 1).

P. H. Chen et al. , IEEE Communications Letters, vol. 17, no. 5, May, 2013.

  However, even if a concatenated code is used, there is a case where an erroneous bit cannot be corrected. In this case, there is a problem that data cannot be determined.

  Accordingly, an object is to provide an encoding device and a decoding device capable of improving the decoding performance of concatenated encoded data and further reducing the required C / N, and a semiconductor chip mounted on these devices. It is another object of the present invention to provide an encoding program and a decoding program executed by the device.

  According to the embodiment, the encoding device includes an outer encoding unit and an inner encoding unit. The outer encoding unit performs an outer encoding process on the supplied data while providing a difference in error correction capability for each data length corresponding to the code length of the basic sparse matrix included in the parity check matrix of the spatially coupled LDPC code. To generate outer coded data. The inner encoding unit generates concatenated encoded data by performing an encoding process on the outer encoded data using the spatially coupled LDPC code.

FIG. 1 is a block diagram illustrating a functional configuration of the encoding device according to the present embodiment. FIG. 2 is a diagram showing concatenated encoded data generated by the encoding device shown in FIG. FIG. 3 is a diagram illustrating an outer encoding process performed by the outer encoding unit illustrated in FIG. 1. FIG. 4 is a diagram illustrating a parity check matrix of a spatially coupled LDPC code according to the present embodiment. FIG. 5 is a diagram illustrating an inner encoding process performed by the inner encoding unit illustrated in FIG. 1. FIG. 6 is a diagram illustrating a relationship between concatenated encoded data and a parity check matrix of a spatially coupled LDPC code according to the present embodiment. FIG. 7 is a block diagram illustrating a functional configuration of the decoding device according to the present embodiment. FIG. 8 is a flowchart showing an operation when the inner code decoding unit shown in FIG. 7 decodes concatenated encoded data. FIG. 9 is a diagram showing a decoding process by the inner code decoding unit shown in FIG. FIG. 10 is a flowchart showing an operation when the outer code decoding unit shown in FIG. 7 decodes BCH encoded data. FIG. 11 is a diagram illustrating a decoding process on the BCH encoded data by the outer code decoding unit illustrated in FIG. 7. FIG. 12 is a diagram showing data that has been subjected to inner code decoding using a conventional technique. FIG. 13 is a diagram illustrating data decoded by the inner code decoding unit according to the present embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

(Encoding device)
FIG. 1 is a block diagram illustrating an example of a functional configuration of an encoding device 10 according to the present embodiment. The encoding device 10 illustrated in FIG. 1 is used in, for example, a relay device and a transmission device.

  The encoding apparatus 10 illustrated in FIG. 1 includes, for example, a CPU (Central Processing Unit), a memory used when the CPU executes processing, and an FPGA (Field Programmable Gate Array) that executes predetermined processing according to control from the CPU. ) Etc. The encoding device 10 realizes the function of the outer encoding unit 11 and the function of the inner encoding unit 12 by causing the CPU to execute predetermined processing by the CPU. Note that the encoding device 10 may include a semiconductor chip such as an LSI (Large-Scale Integration) instead of the FPGA. Further, the encoding device 10 may execute a predetermined process by software.

  The encoding device 10 receives streaming data to be transmitted. The encoding device 10 performs the outer encoding process by the outer encoding unit 11 and the inner encoding process by the inner encoding unit 12 on the input streaming data, so that the concatenated encoding shown in FIG. Generate data. Note that the outer encoding process will be described in detail when describing the outer encoding unit 11 (described later). Further, the inner encoding process will be described in detail when describing the inner encoding unit 12 (described later).

  Note that examples of the outer code include a BCH code and an RS code. In the present embodiment, a case where a BCH code is used will be described as an example. In the present embodiment, a spatially coupled LDPC code is used as an example of the inner code.

  FIG. 2 is a diagram illustrating an example of a schematic diagram of concatenated encoded data generated by the encoding device 10 illustrated in FIG. The concatenated encoded data shown in FIG. 2 is a combination of BCH encoded data and spatially coupled LDPC encoded data.

  Specifically, the concatenated encoded data shown in FIG. 2 includes BCH encoded data D1, BCH encoded data D2, BCH encoded data D3, BCH encoded data D4, and spatially coupled LDPC encoded data D5. Combined. The BCH encoded data D1 is obtained by adding a BCH encoded parity bit PB1 corresponding to the data D11 to data D11 of a predetermined bit to be subjected to the outer encoding process. The BCH encoded data D2 is formed by adding a BCH code parity bit PB2 to data D21. The BCH encoded data D3 is formed by adding a BCH code parity bit PB3 to the data D31. The BCH encoded data D4 is formed by adding a BCH code parity bit PB4 to the data D41. The spatially-coupled LDPC encoded data D5 includes BCH encoded data D1 to D4 as information bits, and LDPC code parity bits PB5 are added to the information bits.

  The outer encoding unit 11 receives streaming data to be transmitted. The outer encoding unit 11 performs an outer encoding process on the input streaming data in units of a preset data length.

Data length set in advance is determined based on the parity check matrix H _C spatial coupling LDPC code will be described later. Information part H _I of the check matrix H _C is generated based on the basic sparse H _B having a code length n, the parity length m. In the present embodiment, the code length of the BCH encoded data outer encoding section 11 generates, as the code length of the basic sparse matrix H _B corresponding to the BCH encoded data matches, the outer encoding process The target data length is set. Outer encoding section 11, by performing outer encoding processing to thus set the data length of data, the corresponding basic sparse matrix H the same code length of BCH encoded data and the code length of _B Generate.

At this time, the code length of the BCH encoded data generated by the outer encoding unit 11 is preferably a multiple of 8 bits. This is because, by setting the code length of the BCH encoded data to a multiple of 8 bits, it is possible to perform processing in units of bytes on the concatenated encoded data in the subsequent stage. To a code length of 8 bits multiple of the BCH encoded data, a code length of the basic sparse matrix H _B in the information part H _I of the check matrix H _C spatial bond LDPC codes, and a multiple of 8 bits. Further, the data length of the data included in the BCH encoded data is more preferably a multiple of 8 bits. In this case, while the basic sparse code length of 8 bits multiple of H _B in the information part H _I of the check matrix H _C spatial bond LDPC code, the data length of the data included in the BCH encoded data of 8 bits The encoding rate of the BCH encoded data is adjusted so as to be a multiple.

  Further, the outer encoding unit 11 makes a difference in the error correction capability of the generated BCH encoded data according to the position of the BCH encoded data in the concatenated encoded data. That is, the outer encoding unit 11 determines that the BCH encoded data corresponding to the basic sparse matrix located near the center of the parity check matrix is better than the BCH encoded data corresponding to the basic sparse matrix located near both ends of the parity check matrix. Performs an outer coding process on the streaming data so as to have a high error correction capability.

  As a method of changing the error correction capability, for example, the following method is used. One method is to increase or decrease the coding rate of BCH coded data. Specifically, the outer encoding unit 11 determines that the coding rate of the BCH encoded data corresponding to the basic sparse matrix located near the center of the parity check matrix corresponds to the basic sparse matrix located near both ends of the parity check matrix. An outer encoding process is performed on the streaming data so as to be lower than the encoding rate of the BCH encoded data.

  Another method of changing the error correction capability is to change the generator polynomial of the BCH encoded data. Specifically, the outer encoding unit 11 determines that the minimum Hamming distance of the generator polynomial when generating BCH encoded data corresponding to the basic sparse matrix located near the center of the parity check matrix is near both ends of the parity check matrix. An outer encoding process is performed on the streaming data so as to be larger than the minimum Hamming distance of the generator polynomial when generating BCH encoded data corresponding to the basic sparse matrix.

  Another method of changing the error correction capability is a method of changing an encoding method. For example, the outer encoding unit 11 performs an outer encoding process using an RS code for data corresponding to the basic sparse matrix located near the center of the parity check matrix, and performs data encoding for the data corresponding to the basic sparse matrix located near both ends of the parity check matrix. For the data to be encoded, an outer encoding process using a BCH code is performed. At this time, the error correction capability of the RS encoded data generated by the outer encoding process using the RS code is higher than the error correction capability of the BCH encoded data generated by the outer encoding process using the BCH code. Shall be.

Since the check matrix H _C spatial coupling LDPC code row weight of both upper and lower ends is smaller, the reliability of the bit of the decoded result of the column at both ends is higher than the middle column. Therefore, by setting the error correction capability of the BCH encoded data at the center of the concatenated encoded data higher than the error correction capability of the BCH encoded data at both ends of the concatenated encoded data, the data decoding performance can be efficiently improved. Can be improved.

  FIG. 3 is a diagram schematically illustrating an outer encoding process performed by the outer encoding unit 11 illustrated in FIG. According to FIG. 3, the outer encoding unit 11 applies, to the data D11 having a predetermined capacity from the beginning of the input streaming data, an outer code having an error correction capability lower than that of the outer encoding process for the data D21 and the data D31. A chemical treatment is performed. The outer encoding unit 11 adds the BCH code parity bit PB1 generated by the outer encoding process to the data D11, and generates BCH encoded data D1 having the same code length as the code length of the corresponding basic sparse matrix.

  Subsequently, the outer encoding unit 11 performs an outer encoding process that has a higher error correction capability than the outer encoding process on the data D11 and the data D41 on the data D21 having a preset capacity from the end of the data D11. The outer encoding unit 11 adds the BCH code parity bits PB2 generated by the outer encoding process to the data D21, and generates BCH encoded data D2 having the same code length as the code length of the corresponding basic sparse matrix.

  Subsequently, the outer encoding unit 11 performs an outer encoding process that has a higher error correction capability than the outer encoding process on the data D11 and the data D41 on the data D31 having a preset capacity from the end of the data D21. The outer encoding unit 11 adds the BCH code parity bit PB3 generated by the outer encoding process to the data D31, and generates BCH encoded data D3 having the same code length as the code length of the corresponding basic sparse matrix.

  Subsequently, the outer encoding unit 11 performs an outer encoding process that has a lower error correction capability than the outer encoding process on the data D21 and the data D31 on the data D41 having a predetermined capacity from the end of the data D31. The outer encoding unit 11 adds the BCH code parity bits PB4 generated by the outer encoding process to the data D41, and generates BCH encoded data D4 having the same code length as the code length of the corresponding basic sparse matrix.

  The inner encoding unit 12 receives the BCH encoded data generated by the outer encoding unit 11. Upon receiving a predetermined number of BCH encoded data, the inner encoding unit 12 performs an inner encoding process using a spatially coupled LDPC code on the received BCH encoded data group.

Inner coding unit 12 generates a spatial coupling LDPC encoded data using the parity check matrix _{H C} spatial coupling LDPC code. Check matrix _{H C} spatial coupling LDPC code has a LDGM (Low-Density Generator Matrix) structure, composed of an information part _{H I} and the parity part _{H P.} Figure 4 is a schematic diagram showing an example of a parity check matrix H _C spatial coupling LDPC code according to the present embodiment.

Information part H _I is the code length n, the parity length m sparse matrix (hereinafter, referred to as basic sparse matrix.) Is generated based on H _B. Here, it is assumed that k = nm. The information part H _I, N type (N: 2 or greater natural number) a sparse matrix L number of N · m rows and k columns the sparse matrix of m rows and k columns was bound to the column direction of shifting by m rows and k columns This is a combined matrix of (L + N-1) m rows and L · k columns. N kinds of sparse matrix is generated by distributing the respective elements of the base sparse matrix H _B of m rows and k columns into N or matrix. FIG. 4 shows a case where N = 2, and two types of sparse matrices are represented as H _U and H _L. Basic sparse matrix H _B has a periodic structure in each matrix of m rows and M columns are arranged sparsely 1 the first column in the matrix of each m rows and M columns, the second column and subsequent first column 1 is arranged at a position where 1 is cyclically shifted by q rows. M is m / q.

Parity part H _P is a double diagonal matrix. The bi-diagonal matrix is a matrix in which a diagonal element and an element immediately below the diagonal are set to 1 and all remaining elements are set to 0. The size of the parity part _{H P} is, (L + N-1) m rows, a (L + N-1) m columns. FIG. 4 shows a case where N = 2.

The inner encoding unit 12 uses (L + N-1) m rows and {L · k + (L + N−1) m} columns of the parity check matrix H _C to convert (L + N−1) m information bits into L · k bits of information bits. It generates spatially-coupled LDPC encoded data to which a bit LDPC code parity bit has been added.

  FIG. 5 is a diagram schematically showing an inner encoding process by the inner encoding unit 12 shown in FIG. According to FIG. 5, the inner encoding unit 12 generates spatially-coupled LDPC encoded data D5 in which LDPC code parity bits PB5 are added to BCH encoded data D1 to D4.

FIG. 6 is a diagram schematically illustrating a relationship between concatenated encoded data according to the present embodiment and a parity check matrix of a spatially coupled LDPC code. According to FIG. 6, the position of BCH coded data D1 in concatenated coded data corresponds to the position in the row direction of basic sparse matrix H _B 1 in the parity check matrix of the spatially coupled LDPC code, The position of the encoded data D2 corresponds to the position in the row direction of the basic sparse matrix H _B2 in the parity check matrix of the spatially coupled LDPC code, and the position of the BCH encoded data D3 in the concatenated encoded data and the spatially coupled LDPC code corresponding to the position of the row direction of the base sparse matrix H _{B 3} in the check matrix, and the position of the BCH encoded data D4 in concatenated coding data, the row of the base sparse matrix H _{B 4} in the check matrix of the spatial coupling LDPC code The position in the direction corresponds to the position. Further, the number of BCH encoded data included in the concatenated encoded data is the same as the number of basic sparse matrices included in the parity check matrix.

  As described above, in the present embodiment, the outer encoding unit 11 performs the outer encoding process for each preset data length based on the parity check matrix of the spatially coupled LDPC code. At this time, the outer encoding unit 11 performs the outer encoding process on the predetermined data while making a difference in the error correction capability. Then, the inner encoding unit 12 performs an inner encoding process using a spatially coupled LDPC code on the BCH encoded data on which the outer encoding process has been performed. As a result, the position in the row direction of the basic sparse matrix in the parity check matrix of the spatially coupled LDPC code corresponds to the position of the BCH coded data in the concatenated coded data. Since the correction capability is improved, it is possible to efficiently improve the error correction capability when using the spatially coupled LDPC code.

  Therefore, according to the encoding device 10 according to the present embodiment, the decoding performance of the concatenated encoded data can be improved, and the required C / N can be further reduced.

  In the present embodiment, an example has been described in which the code length of the BCH encoded data generated by the outer encoding unit 11 is the same as the code length of the basic sparse matrix in the parity check matrix of the spatially coupled LDPC code. However, it is not limited to this. The code length of the BCH encoded data generated by the outer encoding unit 11 may be an integral multiple of the code length of the basic sparse matrix in the parity check matrix of the spatially coupled LDPC code. Further, the code length of the basic sparse matrix in the parity check matrix of the spatially coupled LDPC code may be an integer multiple of the code length of the BCH encoded data generated by the outer encoding unit 11.

(Decryption device)
FIG. 7 is a block diagram illustrating a functional configuration of the decoding device 20 according to the present embodiment. The decoding device 20 shown in FIG. 7 is used, for example, in a receiving device or the like.

  The decoding device 20 illustrated in FIG. 7 includes, for example, a CPU, a memory used when the CPU executes a process, an FPGA that executes a predetermined process under the control of the CPU, and the like. The decoding device 20 realizes the function of the inner code decoding unit 21 and the function of the outer code decoding unit 22 by causing the FPGA to execute predetermined processing by the CPU. Note that the decoding device 20 may include a semiconductor chip such as an LSI or an application specific integrated circuit (ASIC) instead of the FPGA. Further, the decoding device 20 may execute a predetermined process by software.

  The inner code decoding unit 21 receives the concatenated coded data. The inner code decoding unit 21 decodes the input concatenated coded data using a known decoding method for decoding an LDPC code. The inner code decoding unit 21 outputs the inner code decoded data to the outer code decoding unit 22.

  The inner code decoder 21 performs a parity check on the data obtained by decoding the inner code for each data corresponding to the basic sparse matrix in the parity check matrix of the spatially coupled LDPC code. That is, the inner code decoding unit 21 determines whether or not an error bit is included in the inner code decoded data for each data corresponding to the basic sparse matrix in the parity check matrix of the spatially coupled LDPC code. The inner code decoding unit 21 outputs a control signal indicating the determination result to the outer code decoding unit 22.

  The outer code decoding unit 22 performs an outer code decoding process on the data obtained by the inner code decoding according to the control signal. That is, when the control signal indicates that the control signal includes an error bit, the outer code decoding unit 22 performs, on the data acquired by inner code decoding, a data unit corresponding to a basic sparse matrix in a parity check matrix of a spatially coupled LDPC code, The decoding process for the BCH code is performed. At this time, the error correction capability of the BCH encoded data included in the data obtained by the inner code decoding differs depending on the position of the BCH encoded data in the concatenated encoded data. The outer code decoding unit 22 has information about the error correction capability of each BCH encoded data in advance. The outer code decoder 22 refers to this information and performs a decoding process suitable for each data corresponding to the basic sparse matrix.

  On the other hand, when the control signal indicates that no error bit is included, the outer code decoding unit 22 extracts information bits from the data obtained by inner code decoding, and outputs the extracted information bits.

  Next, the operation of the decoding device 20 will be described in detail. FIG. 8 is a flowchart illustrating an example of an operation when the inner code decoding unit 21 illustrated in FIG. 7 decodes concatenated encoded data. FIG. 9 is a diagram schematically illustrating a decoding process performed by the inner code decoding unit 21.

  When the concatenated coded data is input, the inner code decoding unit 21 decodes the input concatenated coded data (Step S81). The inner code decoding unit 21 performs a parity check on the data obtained by inner code decoding in a data unit corresponding to a basic sparse matrix in a parity check matrix of a spatially coupled LDPC code, that is, in units of data D6 to D9 shown in FIG. (Step S82), it is determined whether or not the data subjected to the parity check contains an error (Step S83). If an error is included (Yes in step S83), the inner code decoding unit 21 generates a control signal indicating that an error is included (step S84). When no error is included (No in step S83), the inner code decoding unit 21 generates a control signal indicating that no error is included (step S85). The inner code decoder 21 associates the control signal with the data for which the parity check has been completed, and outputs the data and the control signal to the outer code decoder 22 (step S86).

  Subsequently, the inner code decoding unit 21 determines whether or not a parity check has been performed for all the data subjected to the inner code decoding (Step S87). If the parity check has not been completed for all of the inner-code-decoded data (No in step S87), the inner-code decoding unit 21 shifts the processing to step S82, and performs steps until the parity check for all the data is completed. Steps S83 to S86 are repeated. When the parity check has been completed for all of the inner-code decoded data (Yes in step S87), the inner-code decoding unit 21 ends the processing. As a result, a parity check is performed on each of the data D6 to D9 shown in FIG. 9, and a control signal indicating the result of the parity check is output to the outer code decoding unit 22.

  FIG. 10 is a flowchart illustrating an example of an operation when the outer code decoding unit 22 according to the present embodiment decodes BCH encoded data. Note that FIG. 10 illustrates the processing on the BCH encoded data D6 output by the inner code decoding unit 21. FIG. 11 is a diagram schematically illustrating a decoding process on the BCH encoded data D6 to D9 by the outer code decoding unit 22.

  The outer code decoding unit 22 receives the data D6 subjected to the inner code decoding by the inner code decoding unit 21 and a control signal associated with the data D6. The outer code decoding unit 22 determines whether or not the received control signal indicates that the data D6 includes an error (Step S101). When the control signal indicates that the control signal includes an error (Yes in step S101), the outer code decoding unit 22 determines the position of the data D6 in the concatenated encoded data based on, for example, the data length from the first bit of the concatenated encoded data. To judge. The outer code decoding unit 22 decodes the data D6 by a decoding method corresponding to the determined position (Step S102).

  When the control signal indicates that no error is included (No in step S101), the outer code decoding unit 22 extracts information bits from data corresponding to the control signal (step S103). The outer code decoding unit 22 outputs the information bits obtained by the outer code decoding or the extracted information bits to the subsequent stage (Step S104), and ends the process.

  The outer code decoding unit 22 performs the processing of steps S101 to S104 shown in FIG. 10 on the data D7, D8, and D9 shown in FIG. 11, and acquires data D71, D81, and D91.

  As described above, in the present embodiment, the inner code decoding unit 21 performs the decoding process on the input concatenated coded data with respect to the LDPC code. Then, the outer code decoding unit 22 decodes the data obtained by the inner code decoding based on the basic sparse matrix in the check matrix of the spatially coupled LDPC code.

  Therefore, according to the decoding device 20 of the present embodiment, it is possible to improve the decoding performance of the concatenated data and further reduce the required C / N.

Further, in the present embodiment, the inner code decoding unit 21 performs a parity check on the data obtained by decoding the inner code for each data corresponding to the basic sparse matrix in the parity check matrix of the spatially coupled LDPC code. Then, the outer code decoding unit 22 skips the outer code decoding by the outer code decoding unit 22 when no error bit is included in the inner code decoded data. As a result, the processing speed in the decoding device 20 is improved while maintaining the reliability. As described above, since the check matrix H _C spatial coupling LDPC code smaller row weight of both upper and lower ends, the reliability of the bit of the decoded result of the column at both ends is higher than the middle column. For this reason, as shown in FIGS. 12 and 13, errors are likely to concentrate on a portion corresponding to the central basic sparse matrix. Therefore, as shown in FIG. 13, if the segment of the BCH encoded data matches the segment of the basic sparse matrix, the BCH encoded data that can be skipped without including an error increases. In FIG. 12, since an error straddles two BCH encoded data, any of the BCH encoded data cannot be skipped. On the other hand, in FIG. 13, since errors are concentrated only on the right BCH encoded data, decoding of the left BCH encoded data can be skipped.

  In the present embodiment, an example has been described in which the inner code decoding unit 21 generates a control signal indicating a determination result. However, it is not limited to this. The inner code decoding unit 21 may generate the control signal only when it is determined that the error bit is not included as a result of the parity check.

  Further, in the present embodiment, an example is described in which the concatenated encoded data includes four BCH encoded data, but the number of BCH encoded data included in the concatenated encoded data is not limited to four.

  Also, in the present embodiment, an example has been described in which outer code decoding section 22 performs outer code decoding on a BCH code. However, it is not limited to this. If the encoding device 10 employs the RS code, the outer code decoding unit 22 performs decoding processing on the RS code. Also, when the outer encoding unit 11 of the encoding device 10 realizes the difference in error correction capability by a difference in encoding method, for example, BCH encoding and RS encoding, the outer code decoding unit 22 , BCH code and RS code may be selectively used.

  Although an embodiment of the present invention has been described, this embodiment has been presented by way of example only, and is not intended to limit the scope of the invention. This embodiment can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and equivalents thereof.

  DESCRIPTION OF SYMBOLS 10 ... Encoding device, 11 ... Outer encoding part, 12 ... Inner encoding part, 20 ... Decoding device, 21 ... Inner code decoding part, 22 ... Outer code decoding part

Claims (6)

For the supplied data, for each data length set such that the code length of the basic sparse matrix included in the parity check matrix of the spatially coupled LDPC code matches the code length of the outer coded data after the outer coding process By performing the outer encoding process to the outer encoding unit that generates outer encoded data,
An inner encoding unit that generates concatenated encoded data by performing encoding processing using the spatially coupled LDPC code on the outer encoded data,
The outer encoding unit, the outer coded data corresponding to the basic sparse matrix located near the center of the parity check matrix, than the outer coded data corresponding to the basic sparse matrix located near both ends of the parity check matrix Encoding apparatus for performing the outer encoding process so as to have a high error correction capability . The outer encoding unit, the outer coded data corresponding to the basic sparse matrix located near the center of the parity check matrix, than the outer coded data corresponding to the basic sparse matrix located near both ends of the parity check matrix as is the coding rate is low, the encoding apparatus according to claim 1, wherein implementing the outer coding processing. For the supplied data, for each data length set such that the code length of the basic sparse matrix included in the parity check matrix of the spatially coupled LDPC code matches the code length of the outer coded data after the outer coding process By performing the outer encoding process to the outer encoding unit that generates outer encoded data,
An inner encoding unit that generates concatenated encoded data by performing encoding processing using the spatially coupled LDPC code on the outer encoded data,
The outer encoding unit, the outer coded data corresponding to the basic sparse matrix located near the center of the parity check matrix, than the outer coded data corresponding to the basic sparse matrix located near both ends of the parity check matrix A semiconductor chip for performing the outer encoding process so as to have a high error correction capability . The outer encoding unit, the outer coded data corresponding to the basic sparse matrix located near the center of the parity check matrix, than the outer coded data corresponding to the basic sparse matrix located near both ends of the parity check matrix 4. The semiconductor chip according to claim 3 , wherein the outer coding processing is performed so that the coding rate is also low. For the supplied data, for each data length set such that the code length of the basic sparse matrix included in the parity check matrix of the spatially coupled LDPC code matches the code length of the outer coded data after the outer coding process in the outer encoding process is subjected to a first process for generating outer code data,
By performing an encoding process on the outer encoded data using the spatially coupled LDPC code, a second process of generating concatenated encoded data is performed by a computer of an encoding device.
In the first processing, the outer encoding processing is performed such that outer encoded data corresponding to a basic sparse matrix located near the center of the parity check matrix is converted to a basic sparse matrix located near both ends of the parity check matrix. An encoding program implemented to have a higher error correction capability than the corresponding outer encoded data . In the first processing, the outer encoding processing is performed such that outer encoded data corresponding to a basic sparse matrix located near the center of the parity check matrix is converted to a basic sparse matrix located near both ends of the parity check matrix. The encoding program according to claim 5 , wherein the encoding program is executed such that the encoding rate is lower than the corresponding outer encoded data.