Construction method of multi-code rate compatible LDPC code and its decoder

A technology of LDPC codes and construction methods, applied in the information field, can solve the problems of increased difficulty in the construction of low code rate H matrix, increased construction algorithm complexity, increased algorithm complexity, etc.

Inactive Publication Date: 2007-10-03
PEKING UNIV
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  • Abstract
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  • Claims
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Problems solved by technology

This makes the complexity of the construction algorithm increase sharply with the increase of the number of code rates
Third, the method requires that the column weight distribution of the H matrix of all code rates re

Method used

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  • Construction method of multi-code rate compatible LDPC code and its decoder
  • Construction method of multi-code rate compatible LDPC code and its decoder
  • Construction method of multi-code rate compatible LDPC code and its decoder

Examples

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Embodiment 1

[0105] Embodiment 1: Construct fixed-length irregular multi-code rate permutation matrix LDPC code

[0106] The following specific description utilizes the construction method of the present invention to construct a code length of 8064 bits, and the code rate is 7 / 8, 3 / 4, the process of the multi-code rate LDPC system code of 1 / 2:

[0107] Step 1, determine the parameters of the H matrix. Known code length N=8064, then check equation number M=1008 when code rate is 7 / 8, check equation number M=2016 when code rate is 3 / 4, check equation number when code rate is 1 / 2 is 4032, the size of the H matrix is ​​1008×8064, 2016×8064, 4032×8064 respectively. Find the factors of M and N respectively, we can get N=112×72, M 1 =112×9, M 2 =112×18, M 3 =112×36, so we can choose the size of each sub-block to be 112×112, and the H matrix with different code rates can be divided into 9×72, 18×72, and 36×72 sub-blocks;

[0108] Step 2, use the density deduction method to determine R 1 Dime...

Embodiment 2

[0136] Embodiment 2: Decoder

[0137] The overall structure of the decoder is shown in Figure 15, which can be divided into four parts: Controller (control module), Memory (memory), VNU (variable node computing unit) and CNU (check node computing unit).

[0138] Among them, a total of 72 variable node calculation units are required, and a total of 45 check node calculation units are required. The decoding algorithm can use a simplified algorithm of the sum-product algorithm—the minimum sum algorithm. Since there are 279 non-zero permutation matrices of the H matrix with a code rate of 7 / 8 in the constructed multi-code rate H matrix, the H matrices of other code rates are all split from this matrix, so the multi-code rate decoder A codeword with a decoding rate of 7 / 8 requires a total of 279 dual-port RAMs with a size of 112×7bits (here, the quantization width is 7). When the code rate is other values, the decoder multiplexes these 279 dual-port RAMs. , they serve as storage u...

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Abstract

A method for structuring multi-code rate compatible LDPC code includes carrying out sequencing from high to low as per code rate, distributing dimensionality in following to constraint conditions, using block-PEG algorithm to structure out H matrix of LDPC code with highest code rate, utilizing said matrix as reference to restructure H matrix with different code rate as per code rate order from high to low, making said restructuring obey on constraint conditions and setting zero element position in H matrix of high code rate LDPC code still to be zero element in H matrix of low code rate.

Description

technical field [0001] The invention relates to a channel coding technology, in particular to a construction method of a multi-code rate compatible LDPC code, and belongs to the field of information technology. Background technique [0002] Channel coding technology, as the basic technology to ensure the reliable transmission of communication system, has been developed rapidly in the past ten years. A large number of channel codings represented by Turbo code and LDPC code (low density parity check code) can approach the theoretical limit one after another. It has been discovered and studied deeply, among which LDPC code has received special attention in recent years. In the formulation of various communication standards, it is widely considered to be able to replace Turbo code and become the main channel coding scheme of the next generation communication system. Since the actual communication system often requires multiple rate channel codes to provide different error correc...

Claims

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Application Information

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IPC IPC(8): H03M13/00H03M13/11
Inventor 乔华管武董明科梁庆林项海格
Owner PEKING UNIV
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