Encoding method for low code rate LDPC code

A technology of LDPC codes and coding methods, applied in error detection coding using multi-bit parity bits, error correction/detection using block codes, data representation error detection/correction, etc. Capacity limitations, etc.

Inactive Publication Date: 2009-07-22
HUAZHONG UNIV OF SCI & TECH
View PDF0 Cites 15 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The most primitive low-rate channel coding schemes are Hadamard codes and super-orthogonal convolutional codes. These

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Encoding method for low code rate LDPC code
  • Encoding method for low code rate LDPC code
  • Encoding method for low code rate LDPC code

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0059] For q=3, low-rate LDPC codes with code rate R=1 / 4=0.25, take different code lengths N=64800, 16000, 8000, 4000, 2000, 1000, and the size of the permutation matrix Q is n=16200, 4000 respectively , 2000, 1000, 500, 250, the simulation conditions are 200 maximum iterations and 1000 transmission packets.

[0060] Their bit error rate and signal-to-noise ratio curves on the Gaussian white noise channel are as follows figure 2 shown. Depend on figure 2 It can be seen that the 1 / 4 low-rate LDPC code has the characteristics of better performance as the code length increases. When the code length is 64800, the bit error rate is 10 -7 When , the signal-to-noise ratio is about 0.8dB, and the distance from the Shannon limit of 1 / 4 code rate is 1.593dB. Compared with 9.6dB of uncoded BPSK, the coding gain of 9.8dB can be obtained. The concatenated code scheme of the 1 / 6 code rate convolutional code and the variable-length RS code deployed on the Galileo space station has a bi...

example 2

[0062] For q=5, 6, code rate R=1 / 6, 1 / 7 low-rate LDPC codes, take the same code length N=20160, the size of the permutation matrix Q is respectively: n=3360, 2880, and the simulation condition is still 200 maximum iterations, 1000 transmission packets.

[0063] image 3 The BER and SNR characteristic curves of 1 / 6 and 1 / 7 code rate 20160 code length low-rate LDPC codes are demonstrated. It can be seen from the figure that the performance of the 1 / 6 rate LDPC code is better than that of the 1 / 7 LDPC code, but the two are very close. This shows that the performance of low-rate LDPC codes is not getting better as the code rate decreases. The best performance is the 1 / 6 rate LDPC code, which is in 10 -6 When the bit error rate, the signal-to-noise ratio is 0.478dB, the distance from the Shannon limit (-1.061dB) is 1.534dB, and the coding gain provided is 10.12dB. 1 / 7 rate LDPC code, it is in 10 -6 When the bit error rate, the signal-to-noise ratio is 0.52dB, the distance from...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
Snraaaaaaaaaa
Login to view more

Abstract

The invention discloses an encoding method of low bit-rate LDPC (Low Density Parity Check) code, including the following steps: step 1, matrixes H and H are respectively constructed, the H matrix is a diagonal matrix, H is an array matrix with q multiplied by 1 and consists of q end-around-shift permutation matrixes Q; the permutation matrix Q consists of b multiplied by b step permutation matrixes Q having row weight and line weight of 1, at most one element of 1 on each diagonal line and the rest elements of 0; step 2, an H matrix with the size of equal to bq multiplied b(q+1) is constructed; step 3, check vector c is constructed, c is equal to (p1, 1=1, 2, ..., M), p1 represents the value of any first check bit, and M is the length of check bit; step 4, according to the check vector c=(p1), the inputted information vector c is equal to (dj), and coded code word c=(cc) is obtained. In the method of the invention, an algebraic method used by end-around-shift value of Q permutation matrix leads belief propagation iterative decoding algorithm to be more easily realized in parallel; bidiagonal matrix structural characteristic of H matrix can encode low rate LDPC code in a recursion manner, and has linear time computing complexity. The simulation performance is superior to the performance of the existing low rate error correcting code, thereby being capable of reaching a signal noise ratio of 0.4 dB and having ratio compatibility.

Description

technical field [0001] The invention belongs to the technical field of information theory channel coding, and in particular relates to a coding method of a low code rate low density parity check (LDPC) code. The invention is a technique for improving the reliability of information transmission, which can be applied in multiple wireless communication fields such as space communication, satellite communication, mobile communication and broadband wireless communication. Background technique [0002] First, briefly introduce the research and application status of low-rate codes in the field of error-correcting codes: 1) In 1992, a concatenated code scheme was deployed on the Galileo space station. Its inner code is a convolutional code with a code rate of 1 / 6. The decoding uses a large Viterbi decoder, and the outer code is a variable-length RS code. The operating signal-to-noise ratio of this scheme is E b / N 0 =0.8dB, the bit error rate is P b (E)≈2×10 -7 , the actual codi...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): H03M13/11
Inventor 彭立朱光喜
Owner HUAZHONG UNIV OF SCI & TECH
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap