Short-block LDPC codes design with semi-random parity-check matrix

2013 ◽  
Author(s):  
Qingshuang Zhang ◽  
Aijun Liu ◽  
Jingbo Mao
Keyword(s):  
Ldpc Codes ◽  
Parity Check ◽  
Parity Check Matrix ◽  
Check Matrix

New Optical Codes Based on Construction of Parity Check Matrix of LDPC Codes

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohammed Amine Tehami ◽  
Chahinaz Kandouci ◽  
Ali Djebbari
Keyword(s):  
Code Division Multiple Access ◽  
Cross Correlation ◽  
Direct Detection ◽  
Ldpc Codes ◽  
Parity Check ◽  
Parity Check Matrix ◽  
Check Matrix ◽  
Eye Pattern ◽  
Balanced Detection ◽  
Code Division Multiple

AbstractIn this paper, new spectral optical codes based on the construction parity check matrix of LDPC codes were designed and implemented in an optical code-division multiple access communication system. Two types optical family codes can be obtained with respectively a cross correlation of {\lambda _c} = 0 and {\lambda _c} = 1. In each case, the codes can either be decoded using the direct detection or the balanced detection. Performance was evaluated by referring to the Q factor, the bit error rate and the eye pattern diagrams using Optisystem 9.0.

scholarly journals On the Design of Punctured Low Density Parity Check Codes for Variable Rate Systems

2017 ◽  
Vol 1 (2) ◽  
pp. 88 ◽  
Author(s):  
Marco Baldi ◽  
Franco Chiaraluce
Keyword(s):  
Ldpc Codes ◽  
The Other ◽  
Variable Rate ◽  
Parity Check ◽  
Pragmatic Approach ◽  
Parity Check Matrix ◽  
Tanner Graph ◽  
Low Density Parity Check ◽  
Check Matrix ◽  
Parity Check Codes

The authors face the problem of designing good LDPC codes for applications requiring variable, that is adaptive, rates. More precisely, the object of the paper is twofold. On one hand, we propose a deterministic (not random) procedureto construct good LDPC codes without constraints on the code dimension and rate. The method is based on the analysis and optimization of the local cycles length in the Tanner graph and gives the designer the chance to control complexity of the designed codes. On the other hand, we present a novel puncturing strategy which acts directly on the parity check matrix of the code, starting from the lowest rate needed, in order to allow the design of higher rate codes avoiding additional complexity of the co/decoding hardware. The efficiency of the proposed solution is tested through a number of numerical simulations. In particular, the puncturing strategy is applied for designing codes with rate variable between 0.715 and 0.906. The designed codes are used in conjunction with M-QAM constellations through a pragmatic approach that, however, yields very promising results.

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