# US 2014/0157079 A1 · Low density parity check code for terrestrial cloud broadcast

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- Number: US 2014/0157079 A1
- Document ID: US20140157079A1
- Status: Published application
- Kind: A1
- Application number: 13/906,843
- Filed: 2013-05-31
- Published: 2014-06-05
- Earliest claimed: 2012-06-01
- Assignees: Electronics and Telecommunications Research Institute
- Applicants: Electronics and Telecommunications Research Institute
- Inventors: Sung Ik PARK; Heung Mook KIM; Nam Ho HUR
- Web page: https://patentgrep.com/patent/US20140157079A1

## CPC

- H03M 13/1185: {wherein the parity-check matrix comprises a part with a double-diagonal}
- H03M 13/1105: {Decoding}
- H03M 13/116: {Quasi-cyclic LDPC [QC-LDPC] codes, i.e. the parity-check matrix being composed of permutation or circulant sub-matrices}
- H03M 13/1165: {QC-LDPC codes as defined for the digital video broadcasting [DVB] specifications, e.g. DVB-Satellite [DVB-S2]}
- H03M 13/1168: {wherein the sub-matrices have column and row weights greater than one, e.g. multi-diagonal sub-matrices}
- H03M 13/616: {Matrix operations, especially for generator matrices or check matrices, e.g. column or row permutations}
- H03M 13/6552: {DVB-T2}
- H03M 13/6555: {DVB-C2}
- H04L 1/0041: {Arrangements at the transmitter end}
- H04L 1/0058: {Block-coded modulation}
- H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Provided is an LDPC (Low Density Parity Check) code for terrestrial cloud broadcast. A method of encoding input information based on an LDPC (Low Density Parity Check) includes receiving information and encoding the input information with an LDPC codeword using a parity check matrix, wherein the parity check matrix may have a structure obtained by combining a first parity check matrix for an LDPC code having a higher code rate than a reference value with a second parity check matrix for an LDPC code having a lower code rate than the reference value.

## Claims

### Claim 1

A method of encoding input information based on an LDPC (Low Density Parity Check), the method comprising:
receiving information; and
encoding the input information with an LDPC codeword using a parity check matrix, wherein the parity check matrix has a structure obtained by combining a first parity check matrix for an LDPC code having a higher code rate than a reference value with a second parity check matrix for an LDPC code having a lower code rate than the reference value.

### Claim 2 (depends on 1)

The method of claim 1, wherein the parity check matrix includes a zero matrix, an identity matrix, and a dual diagonal matrix.

### Claim 3 (depends on 2)

The method of claim 2, wherein the encoded LDPC codeword includes a systematic part corresponding to the input information, a first parity part corresponding to the dual diagonal matrix, and a second parity part corresponding to the identity matrix.

### Claim 4 (depends on 3)

The method of claim 3, wherein said encoding comprises:
calculating the first parity part using the first parity check matrix and the input information; and
calculating the second parity part using the second parity check matrix based on the input information and the calculated first parity part.

### Claim 5 (depends on 2)

The method of claim 2, wherein an element matrix of the dual diagonal matrix constitutes a dual diagonal line and is an identity matrix, and a remaining element matrix of the dual diagonal matrix is a zero matrix.

### Claim 6 (depends on 2)

The method of claim 2, wherein an element matrix of the dual diagonal matrix constituting a dual diagonal line is continuous to an element matrix that constitutes a diagonal line of the identity matrix.

### Claim 7 (depends on 2)

The method of claim 2, further comprising, before said encoding,
determining a code rate of the LDPC code; and
determining a size of the dual diagonal matrix according to the determined code rate.

### Claim 8 (depends on 1)

The method of claim 1, wherein the parity check matrix includes a zero matrix and a circulant permutation matrix.

### Claim 9

An LDPC encoder comprising:
an input unit receiving information; and
an encoding unit encoding the input information with an LDPC codeword using a parity check matrix, wherein the parity check matrix has a structure obtained by combining a first parity check matrix for an LDPC code having a higher code rate than a reference value with a second parity check matrix for an LDPC code having a lower code rate than the reference value.

### Claim 10 (depends on 9)

The LDPC encoder of claim 9, wherein the parity check matrix includes a zero matrix, an identity matrix, and a dual diagonal matrix.

### Claim 11 (depends on 10)

The LDPC encoder of claim 10, wherein the encoded LDPC codeword includes a systematic part corresponding to the input information, a first parity part corresponding to the dual diagonal matrix, and a second parity part corresponding to the identity matrix.

### Claim 12 (depends on 11)

The LDPC encoder of claim 11, wherein the encoding unit encodes the input information by calculating the first parity part using the first parity check matrix and the input information; and calculating the second parity part using the second parity check matrix based on the input information and the calculated first parity part.

### Claim 13 (depends on 10)

The LDPC encoder of claim 10, wherein an element matrix of the dual diagonal matrix constitutes a dual diagonal line and is an identity matrix, and a remaining element matrix of the dual diagonal matrix is a zero matrix.

### Claim 14 (depends on 10)

The LDPC encoder of claim 10, wherein an element matrix of the dual diagonal matrix constituting a dual diagonal line is continuous to an element matrix that constitutes a diagonal line of the identity matrix.

### Claim 15 (depends on 10)

The LDPC encoder of claim 10, further comprising a determining unit determining a code rate of the LDPC code; and determining a size of the dual diagonal matrix according to the determined code rate.

### Claim 16 (depends on 9)

The LDPC encoder of claim 9, wherein the parity check matrix includes a zero matrix and a circulant permutation matrix.

### Claim 17

A method of decoding an LDPC code by an LDPC (Low Density Parity Check) decoder, the method comprising:
receiving an LDPC codeword encoded by a parity check matrix; and
decoding the received LDPC codeword using the parity check matrix, wherein the parity check matrix has a structure obtained by combining a first parity check matrix for an LDPC code having a higher code rate than a reference value with a second parity check matrix for an LDPC code having a lower code rate than the reference value.

### Claim 18 (depends on 17)

The method of claim 17, wherein the parity check matrix includes a zero matrix, an identity matrix, and a dual diagonal matrix.

### Claim 19 (depends on 18)

The method of claim 18, wherein the encoded LDPC codeword includes a systematic part corresponding to the input information, a first parity part corresponding to the dual diagonal matrix, and a second parity part corresponding to the identity matrix.

### Claim 20 (depends on 18)

The method of claim 18, wherein the parity check matrix includes a zero matrix and a circulant permutation matrix.