光通信系統(tǒng)中LDPC碼的代數(shù)構(gòu)造方法研究
發(fā)布時間：2018-07-13 16:16
【摘要】：隨著社會信息化進程的不斷推進，現(xiàn)有的各種視頻業(yè)務以及剛剛商用化的4G對帶寬需求劇增，進而對光通信系統(tǒng)的傳輸容量需求也不斷增加。如何實現(xiàn)高可靠性、長距離、大容量、低成本的傳輸是高速光傳輸技術(shù)面臨的最大挑戰(zhàn)。信道編碼技術(shù)是一種提高傳輸系統(tǒng)可靠性的有效方法。而低密度奇偶校驗（Low-densityParity-check, LDPC）碼作為信道編碼技術(shù)中一種極其重要的參考碼型，憑借其良好的糾錯性能，已成為近年來信道編碼技術(shù)研究的熱點。準循環(huán)低密度奇偶校驗（Quasi-cyclic Low-density Parity-check, QC-LDPC）碼又是一種具有碼長、碼率選擇更靈活、編碼復雜度更低、在光通信系統(tǒng)中具有更好應用前景的LDPC碼。因此，本文對光通信系統(tǒng)中LDPC碼的代數(shù)構(gòu)造方法進行了深入的研究。 本論文的選題來源于重慶市自然科學基金項目“高速光通信系統(tǒng)中SFEC碼型的新穎構(gòu)造機理研究”，（CSTC,2010BB2409）。主要完成了以下幾項工作： （1）闡述了LDPC碼的基礎(chǔ)理論原理并對LDPC碼的編譯碼理論進行了探討，仿真驗證了影響LDPC碼糾錯性能的主要因素。并對光通信系統(tǒng)中主要模塊進行噪聲分析，基于MATLAB搭建了光通信系統(tǒng)仿真模型，為接下來對LDPC碼的代數(shù)構(gòu)造方法研究以及性能仿真分析做好堅實的鋪墊工作。 （2）在考慮光通信系統(tǒng)高碼率要求的基礎(chǔ)上，結(jié)合LDPC碼代數(shù)構(gòu)造方法中有限域乘法群以及循環(huán)子群的基本特性，提出了QC-LDPC碼的一種新穎構(gòu)造方法。并運用該新穎構(gòu)造方法，構(gòu)造出一種適用于光通信系統(tǒng)高碼率要求的規(guī)則QC-LDPC（5334,4955）碼。仿真分析表明：在碼率為0.93時，利用此構(gòu)造方法所構(gòu)造出的規(guī)則QC-LDPC（5334,4955）碼的糾錯性能明顯要優(yōu)于ITU-T G.709光通信系統(tǒng)標準的RS（255,239）碼以及ITU-T G.975.1中的LDPC（32640,30592）碼。在BER=10-6時，QC-LDPC（5334,4955）碼距離香農(nóng)極限約1.64dB，其凈編碼增益（Net Coding Gain, NCG）比RS（255,239）碼提高了約1.61dB，同時比LDPC（32640,30592）碼提高了約0.9dB，更適用于光通信系統(tǒng)。 （3）在進一步研究有限域的基本特性之后，結(jié)合有限域中元素的逆元特性，設(shè)計出一種滿足行列約束條件的LDPC碼構(gòu)造方法，得到一種新穎的校驗矩陣結(jié)構(gòu)。結(jié)合有限域構(gòu)造QC-LDPC碼的方法，造出一種適用于光通信系統(tǒng)高碼率要求的規(guī)則QC-LDPC（5334,4962）碼。仿真分析表明：在碼率為0.93時，利用此構(gòu)造方法所構(gòu)造出的規(guī)則QC-LDPC（5334,4962）碼的糾錯性能明顯要優(yōu)于RS（255,239）碼。在BER=10-6時，QC-LDPC（5334,4962）碼距離香農(nóng)極限約1.48dB，其凈編碼增益比RS（255,239）碼提高了約1.77dB，，同時比LDPC（32640,30592）碼提高了約1.06dB。該方法構(gòu)造的規(guī)則QC-LDPC（5334,4962）碼可考慮作為應用于光通信系統(tǒng)中的超強前向糾錯碼型中的一種候選碼型。 （4）在完成基于有限域的規(guī)則QC-LDPC碼構(gòu)造之后，本文又進一步探究基于修飾技術(shù)的QC-LDPC碼改進方案。提出一種基于計算機搜索基本矩陣中對六環(huán)數(shù)目影響權(quán)重最大的節(jié)點，利用修飾技術(shù)對權(quán)重大的某個點或者某些點進行“置零”操作，達到減少校驗矩陣中六環(huán)的數(shù)目，進而提高構(gòu)造出LDPC碼型糾錯性能的修飾矩陣選擇方案。利用本文所提出的修飾方案，對本文所提出的基于有限域構(gòu)造的校驗矩陣進行多次修飾改進后可知：第一次修飾和第二次修飾均有效的減少了校驗矩陣中六環(huán)的數(shù)目，并改善了新的校驗矩陣所構(gòu)造的QC-LDPC碼型的糾錯性能，其中經(jīng)過第一次修飾之后，基礎(chǔ)矩陣中六環(huán)的數(shù)目減少了128個，在誤碼率為10-6時，采用修飾技術(shù)后得到新的校驗矩陣構(gòu)造出的非規(guī)則QC-LDPC（5334,4962）-masking-1碼型比修飾前的規(guī)則QC-LDPC（5334,4962）碼型提高約了0.23dB的NCG，并且修飾后校驗矩陣構(gòu)造的碼型保持了與修飾前構(gòu)造碼型相等的碼率，仿真驗證了本文所提出的修飾方案的可行性及其對修飾技術(shù)的研究具有重要的參考意義。
[Abstract]:With the progress of the social information process, the existing video services and the newly commercialized 4G have increased the bandwidth demand, and the demand for the transmission capacity of the optical communication system is also increasing. How to achieve high reliability, long distance, large capacity and low cost transmission is the biggest challenge for high-speed optical transmission technology. Channel coding is the biggest challenge. Code technology is an effective method to improve the reliability of transmission systems, and Low-densityParity-check (LDPC) code is an extremely important reference code type in channel coding technology. With its good error correction performance, it has become a hot spot in the research of channel coding techniques in recent years. Quasi -cyclic Low-density Parity-check, QC-LDPC) code is a kind of LDPC code with long code length, more flexible selection of bit rate, lower coding complexity and better application foreground in optical communication system. Therefore, this paper deeply studies the algebraic construction method of LDPC code in optical communication system.
The topic of this paper comes from the Chongqing Natural Science Foundation Project "Research on the novel structure mechanism of SFEC code in high speed optical communication system" (CSTC, 2010BB2409). The following work is completed mainly:
(1) the basic theory principle of LDPC code is expounded and the coding and decoding theory of LDPC code is discussed. The main factors affecting the error correction performance of LDPC code are verified by simulation. The noise analysis of the main modules in the optical communication system is analyzed, and the simulation model of the optical communication system is built on the basis of MATLAB, and the algebraic construction method of LDPC code is studied for the following. And performance simulation analysis to make a solid paving work.
(2) on the basis of considering the high bit rate requirement of optical communication system, and combining the basic properties of the finite field multiplication group and the cyclic subgroup in the LDPC code algebra construction method, a novel construction method of QC-LDPC code is proposed, and a rule QC-LDPC (53344955) for high bit rate requirement of optical communication system is constructed by using the new construction method. The simulation analysis shows that the error correction performance of the rule QC-LDPC (53344955) code constructed by this method is obviously superior to the RS (255239) code of the ITU-T G.709 optical communication system standard and the LDPC (3264030592) code in ITU-T G.975.1. At BER= 10-6, the QC-LDPC (53344955) code distance to Shannon limit is about 1.64dB, Its net coding gain (Net Coding Gain, NCG) is about 1.61dB higher than RS (255239) code, and increases about 0.9dB over LDPC (3264030592) codes, and is more suitable for optical communication systems.
(3) after further studying the basic characteristics of the finite field and combining the inverse element characteristics of the elements in the finite field, a LDPC code construction method which satisfies the column constraint conditions is designed, and a novel check matrix structure is obtained. A rule QC-L suitable for the high bit rate requirement of optical communication system is created with the method of constructing the QC-LDPC code in the finite field. DPC (53344962) code. The simulation results show that the error correction performance of the rule QC-LDPC (53344962) code constructed by this method is obviously better than that of RS (255239) code when the code rate is 0.93. At BER=10-6, the QC-LDPC (53344962) code is about 1.48dB at the Shannon limit, and its net coding gain is about 1.77dB and is more than LDPC (255239) code. 3264030592) the code QC-LDPC (53344962) code which is constructed by the code about 1.06dB. can be considered as a candidate for the super strong forward error correcting code type applied to the optical communication system.
(4) after the construction of the regular QC-LDPC code based on the finite field, this paper further explores the QC-LDPC code improvement scheme based on the modification technology, and proposes a node with the maximum weight affecting the number of six rings based on the computer search matrix, and uses the modification technique to "zero" operation on a point or point of large weight. In order to reduce the number of six rings in the check matrix, and then improve the modified matrix selection scheme that constructs the error correction performance of the LDPC code, the modified scheme proposed in this paper has been improved by the modification of the check matrix based on the finite domain structure proposed in this paper. The first and second modifications are effectively reduced. The number of six rings in the matrix is checked and the error correction performance of the QC-LDPC code type constructed by the new check matrix is improved. After the first modification, the number of six rings in the basic matrix is reduced by 128. When the error rate is 10-6, the non regular QC-LDPC (53344962) -masking-1 constructed by the new check matrix is obtained after the modification technique is used. The rule QC-LDPC (53344962) code pattern before the code shape ratio improves about 0.23dB's NCG, and the code pattern constructed by the modified check matrix keeps the code rate equal to the pre modified structure code. The simulation proves the feasibility of the modified scheme and it has important reference significance for the study of the modification technology.
【學位授予單位】：重慶郵電大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN929.1;TN911.22
本文編號：2120012
[Abstract]:With the progress of the social information process, the existing video services and the newly commercialized 4G have increased the bandwidth demand, and the demand for the transmission capacity of the optical communication system is also increasing. How to achieve high reliability, long distance, large capacity and low cost transmission is the biggest challenge for high-speed optical transmission technology. Channel coding is the biggest challenge. Code technology is an effective method to improve the reliability of transmission systems, and Low-densityParity-check (LDPC) code is an extremely important reference code type in channel coding technology. With its good error correction performance, it has become a hot spot in the research of channel coding techniques in recent years. Quasi -cyclic Low-density Parity-check, QC-LDPC) code is a kind of LDPC code with long code length, more flexible selection of bit rate, lower coding complexity and better application foreground in optical communication system. Therefore, this paper deeply studies the algebraic construction method of LDPC code in optical communication system.
The topic of this paper comes from the Chongqing Natural Science Foundation Project "Research on the novel structure mechanism of SFEC code in high speed optical communication system" (CSTC, 2010BB2409). The following work is completed mainly:
(1) the basic theory principle of LDPC code is expounded and the coding and decoding theory of LDPC code is discussed. The main factors affecting the error correction performance of LDPC code are verified by simulation. The noise analysis of the main modules in the optical communication system is analyzed, and the simulation model of the optical communication system is built on the basis of MATLAB, and the algebraic construction method of LDPC code is studied for the following. And performance simulation analysis to make a solid paving work.
(2) on the basis of considering the high bit rate requirement of optical communication system, and combining the basic properties of the finite field multiplication group and the cyclic subgroup in the LDPC code algebra construction method, a novel construction method of QC-LDPC code is proposed, and a rule QC-LDPC (53344955) for high bit rate requirement of optical communication system is constructed by using the new construction method. The simulation analysis shows that the error correction performance of the rule QC-LDPC (53344955) code constructed by this method is obviously superior to the RS (255239) code of the ITU-T G.709 optical communication system standard and the LDPC (3264030592) code in ITU-T G.975.1. At BER= 10-6, the QC-LDPC (53344955) code distance to Shannon limit is about 1.64dB, Its net coding gain (Net Coding Gain, NCG) is about 1.61dB higher than RS (255239) code, and increases about 0.9dB over LDPC (3264030592) codes, and is more suitable for optical communication systems.
(3) after further studying the basic characteristics of the finite field and combining the inverse element characteristics of the elements in the finite field, a LDPC code construction method which satisfies the column constraint conditions is designed, and a novel check matrix structure is obtained. A rule QC-L suitable for the high bit rate requirement of optical communication system is created with the method of constructing the QC-LDPC code in the finite field. DPC (53344962) code. The simulation results show that the error correction performance of the rule QC-LDPC (53344962) code constructed by this method is obviously better than that of RS (255239) code when the code rate is 0.93. At BER=10-6, the QC-LDPC (53344962) code is about 1.48dB at the Shannon limit, and its net coding gain is about 1.77dB and is more than LDPC (255239) code. 3264030592) the code QC-LDPC (53344962) code which is constructed by the code about 1.06dB. can be considered as a candidate for the super strong forward error correcting code type applied to the optical communication system.
(4) after the construction of the regular QC-LDPC code based on the finite field, this paper further explores the QC-LDPC code improvement scheme based on the modification technology, and proposes a node with the maximum weight affecting the number of six rings based on the computer search matrix, and uses the modification technique to "zero" operation on a point or point of large weight. In order to reduce the number of six rings in the check matrix, and then improve the modified matrix selection scheme that constructs the error correction performance of the LDPC code, the modified scheme proposed in this paper has been improved by the modification of the check matrix based on the finite domain structure proposed in this paper. The first and second modifications are effectively reduced. The number of six rings in the matrix is checked and the error correction performance of the QC-LDPC code type constructed by the new check matrix is improved. After the first modification, the number of six rings in the basic matrix is reduced by 128. When the error rate is 10-6, the non regular QC-LDPC (53344962) -masking-1 constructed by the new check matrix is obtained after the modification technique is used. The rule QC-LDPC (53344962) code pattern before the code shape ratio improves about 0.23dB's NCG, and the code pattern constructed by the modified check matrix keeps the code rate equal to the pre modified structure code. The simulation proves the feasibility of the modified scheme and it has important reference significance for the study of the modification technology.
【學位授予單位】：重慶郵電大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN929.1;TN911.22
【參考文獻】
相關(guān)期刊論文 前3條
1 袁建國;葉文偉;毛幼菊;;光通信系統(tǒng)中基于LDPC碼的SFEC碼型研究[J];光電子.激光;2009年11期
2 袁建國;許亮;黃勝;王永;;光通信中一種基于有限域循環(huán)子群的QC-LDPC碼構(gòu)造方法[J];半導體光電;2013年06期
3 張曉宏;易小波;劉翔;Peter J.Winzer;;ALU 1006傳送技術(shù)以及向T比特時代的演進(英文)[J];中國通信;2013年04期
本文編號：2120012
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