The ldpc code ’ s parity check matrix generated by this scheme has high girth and can be used to coding directly , the coding complexity is lower . as to the decoding algorithm , i modify the message passing algorithm based on the girth that i can get in the structure of parity check matrix to improve the decoding performance . what is more , the new structure of the parity check matrix is easy to implement with the hardware 接着着重围绕ldpc码的校验矩阵构造方法和译码算法展开讨论,在比特填充算法的基础上提出了一种ldpc码联合编译码方案,通过该方案构造的校验矩阵不仅具有良好的girth分布,而且能直接用于编码,编码的计算复杂度低;在译码方面,利用构造奇偶矩阵过程中girth分布信息,优化解码迭代过程,能有效提高系统性能;并且该方案构造的校验矩阵更易于实际的编译码硬件实现。
At the same time , a novel approach to construction of ldpc codes based on the permutation matrix was proposed which got a parity check matrix with the shortest girth is 6 . these codes keep the advantage of linear encoding and become more flexible . simulations show that the performance of short length codes of this kind is as excellent as other ldpc codes 同时提出一种基于置换阵循环移位的构造方法,得到的校验矩阵围长至少为6 ,且保持编码的线性复杂度,码率灵活,仿真结果验证了置换阵ldpc码码长较短时,在高斯信道下性能接近或超过现有其他构造方式的ldpc码。
This paper made a careful study on a class of quasi - regular ldpc codes which could encode in linear time only making use of their parity matrix such as - rotation ldpc codes . two factors of the minimum distance and girth length were discussed to improve the performance of these ldpc codes 本文着重研究以旋转ldpc码为代表的准规则结构的ldpc码的构造和编码方法,可以直接利用校验矩阵实现快速线性编码,并从码距和围长两个方面,对这类ldpc码字性能进行分析和优化。
Then , the properties of generator and parity - check matrix of turbo codes are presented , the simulation results show that turbo codes are unequally protected . three kinds of constructions of unequal error protection turbo codes are introduced finally . the last chapter is the conclusion and further research issues 另外还给出了turbo码的生成矩阵和一致校验矩阵的形式和特点，论证了turbo码本身所具有的非均匀保护的特性，最后给出了构造非均匀保护turbo码的三种方法。
This thesis offers a comprehensive study on the performance of ldpc codes . the author first presents a new method for construction of irregular ldpc codes based on generator matrix in order to significantly reduce encoding complexity . the simulation results are obtained over an awgn channel , and the obtained results are also compared with those acquired by the traditional approaches 本文在对ldpc码进行了系统的分析和研究的基础上,为了降低编码复杂度,我们首次提出了一种基于生成矩阵的非正规ldpc码的构造方法,并将其性能和传统的基于校验矩阵的ldpc码进行了比较。
Three decoder architectures , parallel , serial and partially - parallel approaches , are analyzed in this thesis . a kind of novel partially - parallel architecture for decoding ldpc code is proposed . the trade - off between the performance of the decoder , hardware complexity and data throughout can be achieved with this partially - parallel architecture for the random parity check matrix 论文分析了三种不同的译码器结构:并行结构、串行结构以及部分并行结构,并提出了一种新颖的部分并行结构的ldpc译码器,较好地解决了当校验矩阵为随机结构时,译码性能、硬件资源和数据吞吐量平衡的问题。
Ldpc code belongs to the linear block code which is encoded by the information sequence multiplies generator matrix . although the parity - check matrix of ldpc code is sparse , the generator matrix is not . the encoding complexity of it is linearly proportional to the square of code length Ldpc码属于线性分组码,线性分组码的通用编码方法是由信息序列根据码的生成矩阵来求相应的码字序列,尽管ldpc码的校验矩阵是非常稀疏的,但它的生成矩阵却并不稀疏,这使得其编码复杂度往往与其码长的平方成正比。
In next mobile communication system to suffice more and more high - speed data service and demand of qos ( quality of service ) many new wireless link layer transport technologies are going to be used such as mimo ( multiple input multiple output ) , ofdm ( orthogonal frequency division multiplexing ) , channel coding and acm ( adaptive coding modulation ) etc . low density parity check ( ldpc ) codes were first discovered in 1960 ’ s which belong to linear block codes with their parity matrix being sparse 下一代移动通信系统为了满足移动用户对高速、宽带数据传输业务不断增长和更高服务质量的要求,采用了许多新的无线链路传输技术,包括多天线发射和接收技术、正交频分复用技术、信道纠错编码技术和自适应编码调制技术等。上世纪60年代提出的低密度校验码,是一种校验矩阵为稀疏矩阵的线性分组码。
