In this paper, a novel soft reliability-based iterative majority-logic decoding algorithm with uniform quantization is proposed for regularly structured low density parity-check(LDPC) codes. A weighted measure is intr...In this paper, a novel soft reliability-based iterative majority-logic decoding algorithm with uniform quantization is proposed for regularly structured low density parity-check(LDPC) codes. A weighted measure is introduced for each check-sum of the parity-check matrix and a scaling factor is used to weaken the overestimation of extrinsic information. Furthermore, the updating process of the reliability measure takes advantage of turbo-like iterative decoding strategy. The main computational complexity of the proposed algorithm only includes logical and integer operations with the bit uniform quantization criterion. Simulation results show that the novel decoding algorithm can achieve excellent error-correction performance and a fast decoding convergence speed.展开更多
In order to meet the needs of high-speed development of optical communication system, a construction method of quasi-cyclic low-density parity-check(QC-LDPC) codes based on multiplicative group of finite field is prop...In order to meet the needs of high-speed development of optical communication system, a construction method of quasi-cyclic low-density parity-check(QC-LDPC) codes based on multiplicative group of finite field is proposed. The Tanner graph of parity check matrix of the code constructed by this method has no cycle of length 4, and it can make sure that the obtained code can get a good distance property. Simulation results show that when the bit error rate(BER) is 10-6, in the same simulation environment, the net coding gain(NCG) of the proposed QC-LDPC(3 780, 3 540) code with the code rate of 93.7% in this paper is improved by 2.18 dB and 1.6 dB respectively compared with those of the RS(255, 239) code in ITU-T G.975 and the LDPC(3 2640, 3 0592) code in ITU-T G.975.1. In addition, the NCG of the proposed QC-LDPC(3 780, 3 540) code is respectively 0.2 dB and 0.4 dB higher compared with those of the SG-QC-LDPC(3 780, 3 540) code based on the two different subgroups in finite field and the AS-QC-LDPC(3 780, 3 540) code based on the two arbitrary sets of a finite field. Thus, the proposed QC-LDPC(3 780, 3 540) code in this paper can be well applied in optical communication systems.展开更多
A novel lower-complexity construction scheme of quasi-cyclic low-density parity-check(QC-LDPC) codes for optical transmission systems is proposed based on the structure of the parity-check matrix for the Richardson-Ur...A novel lower-complexity construction scheme of quasi-cyclic low-density parity-check(QC-LDPC) codes for optical transmission systems is proposed based on the structure of the parity-check matrix for the Richardson-Urbanke(RU) algorithm. Furthermore, a novel irregular QC-LDPC(4 288, 4 020) code with high code-rate of 0.937 is constructed by this novel construction scheme. The simulation analyses show that the net coding gain(NCG) of the novel irregular QC-LDPC(4 288,4 020) code is respectively 2.08 d B, 1.25 d B and 0.29 d B more than those of the classic RS(255, 239) code, the LDPC(32 640, 30 592) code and the irregular QC-LDPC(3 843, 3 603) code at the bit error rate(BER) of 10^(-6). The irregular QC-LDPC(4 288, 4 020) code has the lower encoding/decoding complexity compared with the LDPC(32 640, 30 592) code and the irregular QC-LDPC(3 843, 3 603) code. The proposed novel QC-LDPC(4 288, 4 020) code can be more suitable for the increasing development requirements of high-speed optical transmission systems.展开更多
A family of array codes with a maximum distance separable（MDS） property, named L codes, is proposed. The greatest strength of L codes is that the number of rows（columns） in a disk array does not be restricted by t...A family of array codes with a maximum distance separable（MDS） property, named L codes, is proposed. The greatest strength of L codes is that the number of rows（columns） in a disk array does not be restricted by the prime number, and more disks can be dynamically appended in a running storage system. L codes can tolerate at least two disk erasures and some sector loss simultaneously, and can tolerate multiple disk erasures（greater than or equal to three） under a certain condition. Because only XOR operations are needed in the process of encoding and decoding, L codes have very high computing efficiency which is roughly equivalent to X codes. Analysis shows that L codes are particularly suitable for large-scale storage systems.展开更多
We present an automatic repeat request（ARQ） free space optical（FSO） system, which consists of a pulse position modulation（PPM） hard decision and an ARQ. The new ARQ＇s data error detection is based on a PPM hard...We present an automatic repeat request（ARQ） free space optical（FSO） system, which consists of a pulse position modulation（PPM） hard decision and an ARQ. The new ARQ＇s data error detection is based on a PPM hard decision＇s results and can eliminate the traditional ARQ information redundancy. The results of the numerical simulation have a good agreement with theoretical analysis and show that the ARQ-FSO system can effectively improve the bit error rate（BER） performance of the direct hard decision PPM system. Additionally, the proposed system significantly improves the average throughput efficiency compared to traditional ARQ systems.These characteristics make the ARQ-FSO system suitable for application in low BER and complexity FSO scenarios.展开更多
Embedded RAM blocks（BRAMs） in field programmable gate arrays（FPGAs） are susceptible to single event effects（SEEs） induced by environmental factors such as cosmic rays, heavy ions, alpha particles and so on. As t...Embedded RAM blocks（BRAMs） in field programmable gate arrays（FPGAs） are susceptible to single event effects（SEEs） induced by environmental factors such as cosmic rays, heavy ions, alpha particles and so on. As technology scales, the issue will be more serious. In order to tackle this issue, two different error correcting codes（ECCs）, the shortened Hamming codes and shortened BCH codes, are investigated in this paper. The concrete design methods of the codes are presented. Also, the codes are both implemented in flash-based FPGAs. Finally, the synthesis report and simulation results are presented in the paper. Moreover, heavy-ion experiments are performed,and the experimental results indicate that the error cross-section of the device using the shortened Hamming codes can be reduced by two orders of magnitude compared with the device without mitigation, and no errors are discovered in the experiments for the device using the shortened BCH codes.展开更多
基金supported by the National Natural Science Foundation of China(Nos.61472464,61671091 and 61471075)the Natural Science Foundation of Chongqing Science and Technology Commission(No.cstc2015jcyj A0554)+1 种基金the Program for Innovation Team Building at Institutions of Higher Education in Chongqing(No.J2013-46)the Undergraduate Science Research Training Project for Chongqing University of Posts and Telecommunications(No.A2016-61)
文摘In this paper, a novel soft reliability-based iterative majority-logic decoding algorithm with uniform quantization is proposed for regularly structured low density parity-check(LDPC) codes. A weighted measure is introduced for each check-sum of the parity-check matrix and a scaling factor is used to weaken the overestimation of extrinsic information. Furthermore, the updating process of the reliability measure takes advantage of turbo-like iterative decoding strategy. The main computational complexity of the proposed algorithm only includes logical and integer operations with the bit uniform quantization criterion. Simulation results show that the novel decoding algorithm can achieve excellent error-correction performance and a fast decoding convergence speed.
基金supported by the National Natural Science Foundation of China(No.61571072)the Basic and Advanced Technology Research Project in Chongqing(No.cstc2015jcyjA 40015)
文摘In order to meet the needs of high-speed development of optical communication system, a construction method of quasi-cyclic low-density parity-check(QC-LDPC) codes based on multiplicative group of finite field is proposed. The Tanner graph of parity check matrix of the code constructed by this method has no cycle of length 4, and it can make sure that the obtained code can get a good distance property. Simulation results show that when the bit error rate(BER) is 10-6, in the same simulation environment, the net coding gain(NCG) of the proposed QC-LDPC(3 780, 3 540) code with the code rate of 93.7% in this paper is improved by 2.18 dB and 1.6 dB respectively compared with those of the RS(255, 239) code in ITU-T G.975 and the LDPC(3 2640, 3 0592) code in ITU-T G.975.1. In addition, the NCG of the proposed QC-LDPC(3 780, 3 540) code is respectively 0.2 dB and 0.4 dB higher compared with those of the SG-QC-LDPC(3 780, 3 540) code based on the two different subgroups in finite field and the AS-QC-LDPC(3 780, 3 540) code based on the two arbitrary sets of a finite field. Thus, the proposed QC-LDPC(3 780, 3 540) code in this paper can be well applied in optical communication systems.
基金supported by the National Natural Science Foundation of China(Nos.61472464 and 61471075)the Program for Innovation Team Building at Institutions of Higher Education in Chongqing(No.J2013-46)+1 种基金the Natural Science Foundation of Chongqing Science and Technology Commission(Nos.cstc2015jcyjA 0554 and cstc2013jcyjA 40017)the Program for Postgraduate Science Research and Innovation of Chongqing University of Posts and Telecommunications(Chongqing Municipal Education Commission)(No.CYS14144)
文摘A novel lower-complexity construction scheme of quasi-cyclic low-density parity-check(QC-LDPC) codes for optical transmission systems is proposed based on the structure of the parity-check matrix for the Richardson-Urbanke(RU) algorithm. Furthermore, a novel irregular QC-LDPC(4 288, 4 020) code with high code-rate of 0.937 is constructed by this novel construction scheme. The simulation analyses show that the net coding gain(NCG) of the novel irregular QC-LDPC(4 288,4 020) code is respectively 2.08 d B, 1.25 d B and 0.29 d B more than those of the classic RS(255, 239) code, the LDPC(32 640, 30 592) code and the irregular QC-LDPC(3 843, 3 603) code at the bit error rate(BER) of 10^(-6). The irregular QC-LDPC(4 288, 4 020) code has the lower encoding/decoding complexity compared with the LDPC(32 640, 30 592) code and the irregular QC-LDPC(3 843, 3 603) code. The proposed novel QC-LDPC(4 288, 4 020) code can be more suitable for the increasing development requirements of high-speed optical transmission systems.
基金supported by the National Natural Science Foundation of China under Grant No.61202250
文摘A family of array codes with a maximum distance separable（MDS） property, named L codes, is proposed. The greatest strength of L codes is that the number of rows（columns） in a disk array does not be restricted by the prime number, and more disks can be dynamically appended in a running storage system. L codes can tolerate at least two disk erasures and some sector loss simultaneously, and can tolerate multiple disk erasures（greater than or equal to three） under a certain condition. Because only XOR operations are needed in the process of encoding and decoding, L codes have very high computing efficiency which is roughly equivalent to X codes. Analysis shows that L codes are particularly suitable for large-scale storage systems.
基金supported by the National Natural Science Foundation of China(No.61475049)the National Basic Research Program of China(No.2013CB29204)
文摘We present an automatic repeat request（ARQ） free space optical（FSO） system, which consists of a pulse position modulation（PPM） hard decision and an ARQ. The new ARQ＇s data error detection is based on a PPM hard decision＇s results and can eliminate the traditional ARQ information redundancy. The results of the numerical simulation have a good agreement with theoretical analysis and show that the ARQ-FSO system can effectively improve the bit error rate（BER） performance of the direct hard decision PPM system. Additionally, the proposed system significantly improves the average throughput efficiency compared to traditional ARQ systems.These characteristics make the ARQ-FSO system suitable for application in low BER and complexity FSO scenarios.
基金Supported by National Natural Science Foundation of China(11079045,11179003 and 11305233)
文摘Embedded RAM blocks（BRAMs） in field programmable gate arrays（FPGAs） are susceptible to single event effects（SEEs） induced by environmental factors such as cosmic rays, heavy ions, alpha particles and so on. As technology scales, the issue will be more serious. In order to tackle this issue, two different error correcting codes（ECCs）, the shortened Hamming codes and shortened BCH codes, are investigated in this paper. The concrete design methods of the codes are presented. Also, the codes are both implemented in flash-based FPGAs. Finally, the synthesis report and simulation results are presented in the paper. Moreover, heavy-ion experiments are performed,and the experimental results indicate that the error cross-section of the device using the shortened Hamming codes can be reduced by two orders of magnitude compared with the device without mitigation, and no errors are discovered in the experiments for the device using the shortened BCH codes.
