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REGULAR LOW-DENSITY PARITY-CHECK CODES BASED ON SHIFTED IDENTITY MATRICES
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作者 He Shanbao Zhao Chunming Jiang Ming 《Journal of Electronics(China)》 2006年第1期20-22,共3页
This paper extends the class of Low-Density Parity-Check (LDPC) codes that can be constructed from shifted identity matrices. To construct regular LDPC codes, a new method is proposed. Two simple inequations are adopt... This paper extends the class of Low-Density Parity-Check (LDPC) codes that can be constructed from shifted identity matrices. To construct regular LDPC codes, a new method is proposed. Two simple inequations are adopted to avoid the short cycles in Tanner graph, which makes the girth of Tanner graphs at least 8. Because their parity-check matrices are made up of circulant matrices, the new codes are quasi-cyclic codes. They perform well with iterative decoding. 展开更多
关键词 low-density parity-check (ldpc codes Quasi-cyclic codes Construction of codes Sumproduct decoding
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CONSTRUCTION OF NONSYSTEMATIC LOW-DENSITY PARITY-CHECK CODES BASED ON SYMMETRIC BALANCED INCOMPLETE BLOCK DESIGN
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作者 Lin Dengsheng Li Qiang Li Shaoqian 《Journal of Electronics(China)》 2008年第4期445-449,共5页
This paper studies the nonsystematic Low-Density Parity-Check(LDPC)codes based onSymmetric Balanced Incomplete Block Design(SBIBD).First,it is concluded that the performancedegradation of nonsystematic linear block co... This paper studies the nonsystematic Low-Density Parity-Check(LDPC)codes based onSymmetric Balanced Incomplete Block Design(SBIBD).First,it is concluded that the performancedegradation of nonsystematic linear block codes is bounded by the average row weight of generalizedinverses of their generator matrices and code rate.Then a class of nonsystematic LDPC codes con-structed based on SBIBD is presented.Their characteristics include:both generator matrices andparity-check matrices are sparse and cyclic,which are simple to encode and decode;and almost arbi-trary rate codes can be easily constructed,so they are rate-compatible codes.Because there aresparse generalized inverses of generator matrices,the performance of the proposed codes is only0.15dB away from that of the traditional systematic LDPC codes. 展开更多
关键词 low-density parity-check (ldpc codes Nonsystematic codes Symmetric Balanced Incomplete Block Design (SBIBD) Finite projective geometries
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Low-Complexity Optimization Algorithm for Irregular Low-Density Parity-Check Codes
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作者 左健存 邵宇丰 桂林 《Journal of Donghua University(English Edition)》 EI CAS 2013年第4期330-335,共6页
A low-complexity algorithm is proposed in this paper in order to optimize irregular low-density parity-check (LDPC) codes.The algorithm proposed can calculate the noise threshold by means of a one-dimensional densit... A low-complexity algorithm is proposed in this paper in order to optimize irregular low-density parity-check (LDPC) codes.The algorithm proposed can calculate the noise threshold by means of a one-dimensional density evolution and search the optimal degree profiles with fast-convergence differential evolution,so that it has a lower complexity and a faster convergence speed.Simulation resuits show that the irregular LDPC codes optimized by the presented algorithm can also perform better than Turbo codes at moderate block length even with less computation cost. 展开更多
关键词 irregular low-density parity-check (ldpc codes Turbo codes optimizationCLC number:TN911.22Document code:AArticle ID:1672-5220(2013)04-0330-06
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Low-Density Parity-Check Codes: Research Status and Development Direction
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作者 Jie Xu Zhiyong Zheng Kun Tian 《Journal of Information Security》 2022年第4期257-271,共15页
In this paper, we conclude five kinds of methods for construction of the regular low-density parity matrix H and three kinds of methods for the construction of irregular low-density parity-check matrix H. Through the ... In this paper, we conclude five kinds of methods for construction of the regular low-density parity matrix H and three kinds of methods for the construction of irregular low-density parity-check matrix H. Through the analysis of the code rate and parameters of these eight kinds of structures, we find that the construction of low-density parity-check matrix tends to be more flexible and the parameter variability is enhanced. We propose that the current development cost should be lower with the progress of electronic technology and we need research on more practical Low-Density Parity-Check Codes (LDPC). Combined with the application of the quantum distribution key, we urgently need to explore the research direction of relevant theories and technologies of LDPC codes in other fields of quantum information in the future. 展开更多
关键词 low-density parity-check (ldpc) Parity Check Matrix H Quasi-Cyclic (QC) ldpc Spatially Coupled low-density parity-check (SC-ldpc) codes
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Weighted symbol-flipping decoding algorithm for nonbinary LDPC codes with flipping patterns 被引量:2
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作者 Bing Liu Jun Gao +1 位作者 Wei Tao Gaoqi Dou 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第5期848-855,共8页
A novel low-complexity weighted symbol-flipping algorithm with flipping patterns to decode nonbinary low-density parity-check codes is proposed. The proposed decoding procedure updates the hard-decision received symbo... A novel low-complexity weighted symbol-flipping algorithm with flipping patterns to decode nonbinary low-density parity-check codes is proposed. The proposed decoding procedure updates the hard-decision received symbol vector iteratively in search of a valid codeword in the symbol vector space. Only one symbol is flipped in each iteration, and symbol flipping function, which is employed as the symbol flipping metric, combines the number of failed checks and the reliabilities of the received bits and calculated symbols. A scheme to avoid infinite loops and select one symbol to flip in high order Galois field search is also proposed. The design of flipping pattern's order and depth, which is dependent of the computational requirement and error performance, is also proposed and exemplified. Simulation results show that the algorithm achieves an appealing tradeoff between performance and computational requirement over relatively low Galois field for short to medium code length. 展开更多
关键词 nonbinary low-density parity-check (ldpc codes quasi-cyclic symbol-flipping (SF) decoding.
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Hybrid weighted symbol-flipping decoding for nonbinary LDPC codes
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作者 刘冰 Tao Wei +1 位作者 Dou Gaoqi Gao Jun 《High Technology Letters》 EI CAS 2013年第1期58-62,共5页
A hybrid decoding algorithm is proposed for nonbinary low-density parity-check (LDPC) codes, which combines the weighted symbol-flipping (WSF) algorithm with the fast Fourier trans- form q-ary sum-product algorit... A hybrid decoding algorithm is proposed for nonbinary low-density parity-check (LDPC) codes, which combines the weighted symbol-flipping (WSF) algorithm with the fast Fourier trans- form q-ary sum-product algorithm (FFT-QSPA). The flipped position and value are determined by the symbol flipping metric and the received bit values in the first stage WSF algorithm. If the low- eomplexity WSF algorithm is failed, the second stage FFT-QSPA is activated as a switching strategy. Simulation results show that the proposed hybrid algorithm greatly reduces the computational complexity with the performance close to that of FFT-QSPA. 展开更多
关键词 nonbinary low-density (WSF) hybrid weighted symbol-flipping parity-check (ldpc code (HWSF) iterative decoding weighted symbol-flipping
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DESIGN OF LOW-DENSITY PARITY CHECK CODES FOR MIMO SYSTEMS WITH DOUBLY-ITERATIVE RECEIVERS
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作者 Mei Zhonghui Li Xiaofei 《Journal of Electronics(China)》 2010年第4期553-556,共4页
In this paper, the Multiple Input Multiple Output (MIMO) doubly-iterative receiver which consists of the Probabilistic Data Association detector (PDA) and Low-Density Parity-Check Code (LDPC) decoder is developed. The... In this paper, the Multiple Input Multiple Output (MIMO) doubly-iterative receiver which consists of the Probabilistic Data Association detector (PDA) and Low-Density Parity-Check Code (LDPC) decoder is developed. The receiver performs two iterative decoding loops. In the outer loop, the soft information is exchanged between the PDA detector and the LDPC decoder. In the inner loop, it is exchanged between variable node and check node decoders inside the LDPC decoder. On the light of the Extrinsic Information Transfer (EXIT) chart technique, an LDPC code degree profile optimization algorithm is developed for the doubly-iterative receiver. Simulation results show the doubly-receiver with optimized irregular LDPC code can have a better performance than the one with the regular one. 展开更多
关键词 Probabilistic Data Association (PDA) Multiple-Input Multiple-Output (MIMO) low-density parity-check code (ldpc) Extrinsic Information Transfer (EXIT) chart
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Efficient construction and encoding of QC-LDPC codes by cyclic lifting of protographs
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作者 梁原 张树林 +1 位作者 顾品标 吴乐南 《Journal of Southeast University(English Edition)》 EI CAS 2015年第1期25-30,共6页
Quasi-cyclic low-density parity-check (QC-LDPC) codes can be constructed conveniently by cyclic lifting of protographs. For the purpose of eliminating short cycles in the Tanner graph to guarantee performance, first... Quasi-cyclic low-density parity-check (QC-LDPC) codes can be constructed conveniently by cyclic lifting of protographs. For the purpose of eliminating short cycles in the Tanner graph to guarantee performance, first an algorithm to enumerate the harmful short cycles in the protograph is designed, and then a greedy algorithm is proposed to assign proper permutation shifts to the circulant permutation submatrices in the parity check matrix after lifting. Compared with the existing deterministic edge swapping (DES) algorithms, the proposed greedy algorithm adds more constraints in the assignment of permutation shifts to improve performance. Simulation results verify that it outperforms DES in reducing short cycles. In addition, it is proved that the parity check matrices of the cyclic lifted QC-LDPC codes can be transformed into block lower triangular ones when the lifting factor is a power of 2. Utilizing this property, the QC- LDPC codes can be encoded by preprocessing the base matrices, which reduces the encoding complexity to a large extent. 展开更多
关键词 low-density parity-check (ldpc codes quasi-cyclic ldpc codes cyclic lifting protograph ldpc codes
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DESIGN OF QUASI-CYCLIC LDPC CODES BASED ON EUCLIDEAN GEOMETRIES 被引量:4
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作者 Liu Yuanhua Niu Xinliang +1 位作者 Wang Xinmei Fan Jiulun 《Journal of Electronics(China)》 2010年第3期340-344,共5页
A new method for constructing Quasi-Cyclic (QC) Low-Density Parity-Check (LDPC) codes based on Euclidean Geometry (EG) is presented. The proposed method results in a class of QC-LDPC codes with girth of at least 6 and... A new method for constructing Quasi-Cyclic (QC) Low-Density Parity-Check (LDPC) codes based on Euclidean Geometry (EG) is presented. The proposed method results in a class of QC-LDPC codes with girth of at least 6 and the designed codes perform very close to the Shannon limit with iterative decoding. Simulations show that the designed QC-LDPC codes have almost the same performance with the existing EG-LDPC codes. 展开更多
关键词 low-density parity-check codes (ldpc) Quasi-Cyclic (QC) Euclidean Geometry (EG) Iterative method
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Irregular and regular LDPC codes with high spectrum efficiency modulation in image transmission over fading channel 被引量:1
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作者 MaPiming YuanDongfeng 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2005年第1期26-30,共5页
If the degree distribution is chosen carefully, the irregular low-density parity-check (LDPC) codes can outperform the regular ones. An image transmission system is proposed by combining regular and irregular LDPC cod... If the degree distribution is chosen carefully, the irregular low-density parity-check (LDPC) codes can outperform the regular ones. An image transmission system is proposed by combining regular and irregular LDPC codes with 16QAM/64QAM modulation to improve both efficiency and reliability. Simulaton results show that LDPC codes are good coding schemes over fading channel in image communication with lower system complexity. More over, irregular codes can obtain a code gain of about 0.7 dB compared with regular ones when BER is 10 -4. So the irregular LDPC codes are more suitable for image transmission than the regular codes. 展开更多
关键词 irregular low-density parity-check (ldpc) codes degree distribution image transmission high spectrum efficiency modulation.
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Ensemble of High Performance Structured Binary Convolutional LDPC Codes with Moderate Rates 被引量:1
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作者 Liwei Mu 《China Communications》 SCIE CSCD 2020年第10期195-205,共11页
An algebraic construction methodology is proposed to design binary time-invariant convolutional low-density parity-check(LDPC)codes.Assisted by a proposed partial search algorithm,the polynomialform parity-check matri... An algebraic construction methodology is proposed to design binary time-invariant convolutional low-density parity-check(LDPC)codes.Assisted by a proposed partial search algorithm,the polynomialform parity-check matrix of the time-invariant convolutional LDPC code is derived by combining some special codewords of an(n,2,n−1)code.The achieved convolutional LDPC codes possess the characteristics of comparatively large girth and given syndrome former memory.The objective of our design is to enable the time-invariant convolutional LDPC codes the advantages of excellent error performance and fast encoding.In particular,the error performance of the proposed convolutional LDPC code with small constraint length is superior to most existing convolutional LDPC codes. 展开更多
关键词 algebraic construction (n 2 n−1)codes convolutional low-density parity-check(ldpc)codes fast encoding maximum achievable syndrome former memory large girth
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QUASI-SYSTEMATIC BLOCK-CIRCULANT LDPC CODES
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作者 Xu Ying Wei Guo 《Journal of Electronics(China)》 2008年第5期641-646,共6页
A class of Quasi-Systematic Block-Circulant Low-Density Parity-Check(QSBC-LDPC) codes is proposed.Block-circulant LDPC codes have been studied a lot recently,because the simple structures of their parity-check matrice... A class of Quasi-Systematic Block-Circulant Low-Density Parity-Check(QSBC-LDPC) codes is proposed.Block-circulant LDPC codes have been studied a lot recently,because the simple structures of their parity-check matrices are very helpful to reduce the implementation complexities.QSBC-LDPC codes are special block-circulant LDPC codes with quasi-systematic parity-check ma-trices.The memories for encoders of QSBC-LDPC codes are limited,and the encoding process can be carried out in a simple recursive way with low complexities.Researches show that the QSBC-LDPC codes can provide remarkable performances with low encoding complexities. 展开更多
关键词 low-density parity-check (ldpc codes Quasi-systematic Block-circulant Recursive encoding Cyclic-shifting
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SPARSE SEQUENCE CONSTRUCTION OF LDPC CODES
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作者 He Shanbao Zhao Chunming Shi Zhihua 《Journal of Electronics(China)》 2005年第5期520-523,共4页
This letter proposes a novel and simple construction of regular Low-Density Parity-Check (LDPC) codes using sparse binary sequences. It utilizes the cyclic cross correlation function of sparse sequences to generate co... This letter proposes a novel and simple construction of regular Low-Density Parity-Check (LDPC) codes using sparse binary sequences. It utilizes the cyclic cross correlation function of sparse sequences to generate codes with girth8. The new codes perform well using the sumproduct decoding. Low encodingcomplexity can also be achieved due to the inherent quasi-cyclic structure of the codes. 展开更多
关键词 Block codes low-density parity-check(ldpc codes Regular codes CONSTRUCTION
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APPLICATION OF BEAM SEARCH FOR THE DECODING OF ONE CLASS OF LDPC CODES
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作者 Li Guangwen Feng Guangzeng 《Journal of Electronics(China)》 2008年第4期457-464,共8页
For one class of Low-Density Parity-Check(LDPC)codes with low row weight in theirparity check matrix,a new Syndrome Decoding(SD)based on the heuristic Beam Search(BS),labeledas SD-BS,is put forward to improve the erro... For one class of Low-Density Parity-Check(LDPC)codes with low row weight in theirparity check matrix,a new Syndrome Decoding(SD)based on the heuristic Beam Search(BS),labeledas SD-BS,is put forward to improve the error performance.First,two observations are made andverified by simulation results.One is that in the SNR region of interest,the hard-decision on thecorrupted sequence yields only a handful of erroneous bits.The other is that the true error pattern forthe nonzero syndrome has a high probability to survive the competition in the BS,provided sufficientbeam width.Bearing these two points in mind,the decoding of LDPC codes is transformed into seekingan error pattern with the known decoding syndrome.Secondly,the effectiveness of SD-BS dependsclosely on how to evaluate the bit reliability.Enlightened by a bit-flipping definition in the existingliterature,a new metric is employed in the proposed SD-BS.The strength of SD-BS is demonstrated viaapplying it on the corrupted sequences directly and the decoding failures of the Belief Propagation(BP),respectively. 展开更多
关键词 low-density parity-check (ldpc codes Belief Propagation (BP) Beam Search (BS) Error pattern Pyndrome
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Efficient Early Termination Strategy for LDPC Codes in GPS Systems
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作者 Feng Wang Jin-Hai Li +1 位作者 Jin-Hai Sun Yue-Peng Yan 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2013年第6期118-122,共5页
By exploiting the structural features of L1C messages,a novel Early Termination( ET) strategy is proposed to speed up the decoding of low-density parity-check( LDPC) codes in the GPS system. The proposed strategy is b... By exploiting the structural features of L1C messages,a novel Early Termination( ET) strategy is proposed to speed up the decoding of low-density parity-check( LDPC) codes in the GPS system. The proposed strategy is based on the cyclic redundancy check( CRC) of the messages in the subframes 2 and 3. The simulation results show that average number of iterations of the proposed strategy is less than that of the standard ET strategy,with nearly no degradation in decoding performance. Besides,the proposed ET strategy can be efficiently implemented in a sequential or parallel manner. Thus,the proposed ET strategy is attractive for practical purposes. 展开更多
关键词 GPS system low-density parity-check (ldpc codes early termination (ET) strategy cyclic redundancy check (CRC)CLC number:TN911.22 Document code:AArticle ID:1005-9113(2013)06-0118-05
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PERFORMANCE EVALUATION OF LOW DENSITY PARITY CHECK CODES FOR DIGITAL RADIO MONDIALE (DRM) SYSTEM 被引量:2
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作者 Wang Jiaqing Yu Xiaoyan Wu Lenan 《Journal of Electronics(China)》 2006年第2期189-192,共4页
In Digital Radio Mondiale (DRM) system, achieving good audio quality becomes a challenge due to its limited band-width of 9 or 10kHz and the very bad lading channels. Therefore, DRM needs highly efficient channel co... In Digital Radio Mondiale (DRM) system, achieving good audio quality becomes a challenge due to its limited band-width of 9 or 10kHz and the very bad lading channels. Therefore, DRM needs highly efficient channel coding schemes. This paper, proposes the schemes which use the Low-Density Parity-Check (LDPC) coded Bit-Interleaved Coded Modulation (BICM) schemes for the implementation of DRM systems. Simulation results show that the proposed system is more efficient than the Rate Compatible Punctured Convolutional (RCPC) coded DRM system on various broadcast channels, and may be recommended as a coding technology for Digital Amplitude Modulation Broadcasting (DAMB) systems of China. 展开更多
关键词 low-density parity-check (ldpc codes Digital Radio Mondiale (DRM) Bit Interleaved coded Modulation (BICM) Orthogonal Frequency Division Multiplexing (OFDM)
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Construction of Rate-Compatible(RC) Low-Density Parity-Check(LDPC) Convolutional Codes Based on RC-LDPC Block Codes 被引量:1
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作者 穆丽伟 韩国军 刘志勇 《Journal of Shanghai Jiaotong university(Science)》 EI 2016年第6期679-683,共5页
In this paper,a family of rate-compatible(RC) low-density parity-check(LDPC) convolutional codes can be obtained from RC-LDPC block codes by graph extension method.The resulted RC-LDPC convolutional codes,which are de... In this paper,a family of rate-compatible(RC) low-density parity-check(LDPC) convolutional codes can be obtained from RC-LDPC block codes by graph extension method.The resulted RC-LDPC convolutional codes,which are derived by permuting the matrices of the corresponding RC-LDPC block codes,are systematic and have maximum encoding memory.Simulation results show that the proposed RC-LDPC convolutional codes with belief propagation(BP) decoding collectively offer a steady improvement on performance compared with the block counterparts over the binary-input additive white Gaussian noise channels(BI-AWGNCs). 展开更多
关键词 rate-compatible(RC) low-density parity-check(ldpc) convolutional codes systematic maximum encoding memory belief propagation(BP) decoding
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AN ITERATIVE RELIABILITY-BASED DECODING FOR LDPC CODED MODULATION SYSTEM
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作者 Huang Ping Zhao Chunming Jiang Ming 《Journal of Electronics(China)》 2008年第3期289-293,共5页
In this paper, A Belief Propagation concatenated Orderd-Statistic Decoder (BP-OSD) based on accumulated Log-Likelihood Ratio (LLR) is proposed for medium and short lengths Low Density Parity-Check (LDPC) codes coded B... In this paper, A Belief Propagation concatenated Orderd-Statistic Decoder (BP-OSD) based on accumulated Log-Likelihood Ratio (LLR) is proposed for medium and short lengths Low Density Parity-Check (LDPC) codes coded Bit-Interleaved Coded Modulation (BICM) systems. The accumulated soft output values delivered by every BP iteration are used as reliability values of Soft-Input Soft-Output OSD (SISO-OSD) decoder and the soft output of SISO-OSD is used as a priori probabilities of the demodulator for the next iteration. Simulation results show that this improved algorithm achieves noticeable performance gain with only modest increase in computation complexity. 展开更多
关键词 low-density parity-check (ldpc codes Bit-Interleaved coded Modulation (BICM) Belief Propagation (BP) Soft-Input Soft-Output Ordered Statistics Decoding (SISO-OSD) Log- Likelihood Ratio (LLR)
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DESIGN OF IRREGULAR LDPC CODE WITH UNEQUAL ERROR PROTECTION PROPERTY AND ITS PERFORMANCE ANALYSIS ON IMAGE TRANSMISSION
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作者 Wang Ruihua Yin Liuguo +1 位作者 Yu Quan Lu Jianhua 《Journal of Electronics(China)》 2005年第6期658-662,共5页
Based on the property that high degree variable nodes within an irregular LowDensity Parity-Check (LDPC) code have more powerful error-correcting capability than that of low degree variable nodes, a group of irregular... Based on the property that high degree variable nodes within an irregular LowDensity Parity-Check (LDPC) code have more powerful error-correcting capability than that of low degree variable nodes, a group of irregular LDPC codes with Unequal Error Protection (UEP)property is designed in this letter. Simulation results show that the transmission quality of the image may be effectively improved with this class of irregular LDPC code. 展开更多
关键词 Irregular low-density parity-check (ldpc code Unequal Error Protection (UEP) Image transmission
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DESIGN OF LDPC-CODED BICM USING A SEMI-GAUSSIAN APPROXIMATION
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作者 Huang Jie Zhang Fan Zhu Jinkang 《Journal of Electronics(China)》 2007年第2期174-180,共7页
This paper investigates analysis and design of Low-Density Parity-Check (LDPC) coded Bit Interleaved Coded Modulation (BICM) over Additive White Gaussian Noise (AWGN) channel. It focuses on Gray-labeled 8-ary Ph... This paper investigates analysis and design of Low-Density Parity-Check (LDPC) coded Bit Interleaved Coded Modulation (BICM) over Additive White Gaussian Noise (AWGN) channel. It focuses on Gray-labeled 8-ary Phase-Shift-Keying (8PSK) modulation and employs a Maximum A Posteriori (MAP) symbol-to-bit metric calculator at the receiver. An equivalent model of a BICM communication channel with ideal interleaving is presented. The probability distribution function of log-likelihood ratio messages from the MAP receiver can be approximated by a mixture of symmetric Gaussian densities. As a result semi-Gaussian approximation can be used to analyze the decoder. Extrinsic information transfer charts are employed to describe the convergence behavior of LDPC decoder. The design of irregular LDPC codes reduces to a linear programming problem on two-dimensional variable edge-degree distribution. This method allows irregular code design in a wider range of rates without any limit on the maximum node degree and can be used to design irregular codes having rates varying from 0.5275 to 0.9099. The designed convergence thresholds are only a few tenths, even a few hundredths of a decibel from the capacity limits. It is shown by Monte Carlo simulations that, when the block length is 30,000, these codes operate about 0.62-0.75 dB from the capacity limit at a bit error rate of 10s. 展开更多
关键词 Irregular low-density parity-check (EXIT) charts Semi-Gaussian assumption (ldpc codes EXtrinsic Information Transfer
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