Browsing by Author "Wu, Chi-Jen"

Now showing 1 - 4 of 4

New Construction of LDPC Convolutional Codes
(2008)
Wu, Chi-Jen
;
Chou, Yi-Chun
;
Wang, Chung-Hsuan
;
Chao, Chi-Chao
;
電信工程研究所
In this paper, we propose a new construction of (3,t)-regular low-density parity-check convolutional codes by properly including binomial entries in the parity-check matrices. Both of the upper and lower bounds on free distance are derived for the new codes. Compared with previous constructions, our design can not only avoid codes of girth less than 8 but also provide enlarged free distances for some code rates. Simulation results show that the codes based on the new construction can achieve better bit-error-rate performance and lower error floor.
New Constructions of Variable-Rate QC-LDPC Codes by Adding Column-Blocks or Removing Row-Blocks
(2016-01-01)
Wu, Chi-Jen
;
Wang, Chung-Hsuan
;
Chao, Chi-chao
;
電機工程學系
;
Department of Electrical and Computer Engineering
In this paper, new constructions of variable-rate quasi-cyclic low-density parity-check (QC-LDPC) codes are proposed. The criteria which guarantee that a higher-rate QC-LDPC code can be obtained by adding column-blocks to or removing row-blocks from the parity-check matrix of a given lower-rate QC-LDPC code are derived. Based on these criteria, new families of variable-rate QC-LDPC codes can he constructed. Simulation results show that the constructed codes provide a variety of error protection capabilities against different channel conditions.
UEP Constructions of Quasi-Cyclic Low-Density Parity-Check Codes via Masking
(2017-10-01)
Wu, Chi-Jen
;
Wang, Chung-Hsuan
;
Chao, Chi-chao
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, the algebraic constructions of quasi-cyclic low-density parity-check (QC-LDPC) codes with the unequal error protection (UEP) property are considered. A criterion for constructing such codes via the masking technique is proposed, based on which explicit conditions on the base parity-check matrices and masking matrices to achieve UEP are provided. We also give three specific constructions of UEP QC-LDPC codes. Furthermore, a sufficient condition to ensure strict UEP is presented. Simulation results demonstrate the superiority of our constructed codes over time-sharing schemes. The constructed codes also have competitive error performance against randomly constructed equal-error-protection LDPC codes and irregular UEP LDPC codes designed based on the degree distribution.
Unequal Error Protection QC-LDPC Codes via Masking
(2012)
Wu, Chi-Jen
;
Wang, Chung-Hsuan
;
Chao, Chi-chao
;
電機工程學系
;
Department of Electrical and Computer Engineering
In this paper, a generalized construction of quasi-cyclic low-density parity-check (QC-LDPC) codes for unequal error protection (UEP) is proposed based on the masking technique. We can obtain UEP QC-LDPC codes as long as the Tanner graph of the masking matrix satisfies a general condition which can include our previous UEP construction as a special case. A sufficient condition to have flexible choice of protection levels is then presented. Simulation results show that the constructed codes can indeed provide codeword bits with different bit-error-rate performance.