Combined constructing method for quasi cyclic-low density parity check codes

A low-density check code and construction method technology, which is applied in the field of channel coding in the communication industry, can solve the problems that the complexity of hardware implementation is difficult to further reduce and affect the decoding performance, so as to reduce the impact of decoding performance and excellent error correction The effect of loose performance and optional range

Inactive Publication Date: 2014-04-16
XIAN UNIV OF POSTS & TELECOMM
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AI Technical Summary

Problems solved by technology

[0008] However, although these LDPC construction methods avoid the influence of 4 loops on the performance of iterative decoding, the error correction performance has been improved to a certain extent, but because there are still a lot of short loops in it, the decoding performance is still affected, and the hardware implementation is complicated. It is difficult to further reduce

Method used

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  • Combined constructing method for quasi cyclic-low density parity check codes
  • Combined constructing method for quasi cyclic-low density parity check codes
  • Combined constructing method for quasi cyclic-low density parity check codes

Examples

Experimental program
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Embodiment 2

[0035] Ⅰ. Select two mutually prime integers L 1 =31, L 2 =7, then L=217.

[0036] Ⅱ. Select the row weight, column weight and girth as ρ=7, γ=3, g=8 respectively, and construct the parity check matrix of the array LDPC code its shift matrix is a 31×31 matrix, The element in row i and column j of is (i-1)(j-1)mod L 1 (1≤i,j≤31), delete From line 4 to line 31 of , delete at the same time 1, 2, 3, 6, 7, 9, 11, 12, 13, 27, 29, 30, 31 columns and the 15th to 25th columns, the shift of the shortened array LDPC code with girth g=8 is obtained bit matrix

[0037] Ⅲ. Structure and S(H 1 ) matrices with the same dimension S(H 2 ) are initialized to ∞; then randomly select elements from the set {0,1,2,…,6} as S(H 2 ) in the first row and column; S(H 2 ) The remaining elements are set column by column from left to right, and the elements of each column are set one by one from top to bottom. See step IV for details.

[0038] Ⅳ. Set the elements of a certain row and c...

Embodiment 1

[0042] Embodiment 1 obtains the above-mentioned QC-LDPC code (1573, 1146), and embodiment 2 obtains the above-mentioned code (1519, 870). The additive white Gaussian noise channel (AWGN) under BPSK modulation is used to simulate and verify the error correction performance of the QC-LDPC code obtained in the present invention under the sum-product decoding algorithm. In the simulation process, the maximum number of iterations is set to 50.

[0043] As a comparison, the (3,11)-rule QC-LDPC codes (1573, 1146) obtained according to the existing construction method containing 7510 6-rings and 858 6-rings respectively, and the obtained according to the existing construction method The (3,7) regular QC-LDPC code (1519,870) containing 151032 8-rings is verified by the same simulation.

[0044] figure 1 The middle abscissa is the signal-to-noise ratio E b / N 0 , the vertical axis is the bit error rate (BER), the connection line of ○ represents the bit error rate (BER) of the QC-LDPC...

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Abstract

The invention relates to a combined constructing method for quasi cyclic-low density parity check codes. The method comprises the steps that firstly, two integers L1 and L2 which are relatively prime are selected, wherein L1 is a prime number, and L=L1*L2; secondly, the row weight Rho of a given code parameter is larger than or equal to 1 but smaller than or equal to L1, the column weight gamma of the given code parameter is larger than or equal to 1 but smaller than or equal to L1, and a shift matrix S(H1) of the shortened array LDPC code with the girth g larger than or equal to 6 is constructed; thirdly, a matrix S(H2) is constructed, elements in a first line and a first column are selected from the set {0,1,2,...,L2-1} at random, and the rest elements are arranged from top to bottom and from left to right one by one; fourthly, the number of g-rings, corresponding to a sparse matrix H, in a tanner graph is counted every time the S(H2) is set with one element, and the fewest elements of the g-rings serve as the elements in the column and line; fifthly, the elements in the S(H) are replaced by an L*L cyclic permutation matrix so that the sparse matrix H with the smaller number of g-rings can be obtained to serve as a check matrix of the LDPC code, the construction of the code is finished, and the QC-LDPC codes (1573,1146) and (1519,870) are obtained. The combined constructing method can obtain the QC-LDPC codes with good ring distribution and superior correcting performance and is suitable for China digital sound broadcasting.

Description

technical field [0001] The invention relates to the technical field of channel coding in the communication industry, in particular to a joint construction method of a Quasi Cyclic-Low Density Parity Check (QC-LDPC) based on the Chinese remainder theorem. Background technique [0002] Communication systems are designed to efficiently and reliably transfer information from sources to destinations. The noise that interferes with the communication channel interferes with the transmitted information and reduces the reliability of the communication. Therefore, a key issue in communication system design is how to transmit information effectively and reliably in the presence of random noise interference. The core of channel coding technology is to provide immunity to the information bits to be sent by adding redundancy to resist the influence of noise on information in the communication process and ensure communication reliability. [0003] In 1948, C.E.Shannon of Bell Laboratorie...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03M13/11
Inventor 刘原华
Owner XIAN UNIV OF POSTS & TELECOMM
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