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low-density-parity-check--ldpc
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Performance evaluation of LDPC coded MC-FH-CDMA system over fading channels
, Article 14th IEEE 2003 International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC2003, Beijing, 7 September 2003 through 10 September 2003 ; Volume 2 , 2003 , Pages 1574-1578 ; 0780378229 (ISBN); 9780780378223 (ISBN) ; Haghighat, J ; Nasiri Kenari, M ; Jamali, S. H ; Sharif University of Technology
2003
Abstract
In this paper, we consider the application of Low-Density Parity-Check (LDPC) codes in multi-carrier frequency-hopping (MC-FH) CDMA systems. We evaluate the performance of the coded system in a slowly Rayleigh fading frequency-selective channel using different construction methods of regular LDPC codes. We then compare the results with those of the Super-Orthogonal coded system. Our simulation results show that the LDPC coded scheme significantly outperforms the uncoded and the Super-Orthogonal coded scheme. Finally, we propose a new semi-random construction of regular LDPC code and evaluate its performance in MC-FH-CDMA system. Our numerical results indicate that this new construction...
A PEG construction of finite-length LDPC codes with low error floor
, Article IEEE Communications Letters ; Volume 16, Issue 8 , 2012 , Pages 1288-1291 ; 10897798 (ISSN) ; Asvadi, R ; Banihashemi, A. H ; Sharif University of Technology
2012
Abstract
The progressive-edge-growth (PEG) algorithm of Hu et al. is modified to improve the error floor performance of the constructed low-density parity-check (LDPC) codes. To improve the error floor, the original PEG algorithm is equipped with an efficient algorithm to find the dominant elementary trapping sets (ETS's) that are added to the Tanner graph of the under-construction code by the addition of each variable node and its adjacent edges. The aim is to select the edges, among the candidates available at each step of the original PEG algorithm, that prevent the creation of dominant ETS's. The proposed method is applicable to both regular and irregular variable node degree distributions....
Performance evaluations and comparisons of several LDPC coded MC-FH-CDMA systems
, Article Scientia Iranica ; Volume 13, Issue 4 , 2006 , Pages 337-347 ; 10263098 (ISSN) ; Haghighat, J ; Nasiri Kenari, M ; Jamali, S. H ; Sharif University of Technology
Sharif University of Technology
2006
Abstract
In this paper, the application of regular Low-Density Parity-Check (LDPC) codes in Multi-Carrier Frequency-Hopping (MC-FH) CDMA systems is studied. To this end, different well-known constructions of regular LDPC codes are considered and the performance of LDPC coded MC-FH-CDMA systems, based on these constructions, are evaluated and compared in a frequency-selective slowly Rayleigh fading channel. These results are compared with those previously reported for super-orthogonal convolutionally coded MC-FH-CDMA systems. The simulation results indicate that the LDPC coded MC-FH-CDMA system significantly outperforms the uncoded and super-orthogonal convolutionally coded schemes. To alleviate the...