多进制LDPC码编译码算法优化及应用研究

发布时间：2018-05-07 11:01

本文选题：多进制低密度奇偶校验码 + 低编码复杂度　；参考：《哈尔滨工程大学》2014年博士论文

【摘要】：数字信息在具有时变特性的无线信道中传输时,由于受到噪声的影响会导致接收端不能接收正确的信息,对人们的日常生活造成严重的影响。而大多数实用的通信系统都是基于无线通信的,因此如何提高无线通信的通信质量是需要解决的首要问题之一。而将纠错性能优异的信道编码技术即LDPC码应用于无线通信系统是一种解决无线通信质量问题的有效措施。随着通信技术、互联网技术的不断发展以及用户对高质量的多媒体业务需求的不断增加,未来无线通信技术必须具有提供更高数据传输速率、更高频带利用率以及更高通信质量业务的能力,因此在未来的无线通信中采用的通信技术必须满足高频带利用率、高可靠性的需求。此时多进制LDPC码与二进制LDPC码相比,具有更显著的优势,但其高编译码复杂度阻碍了其实用化进程。因此,对多进制LDPC码的编译码算法进行优化,构造具有较强纠错性能的中短码长LDPC码,对高阶域LDPC码调制一体化方案进行设计以及对多进制LDPC码的应用进行研究,具有重要的理论分析和实际应用意义。论文针对多进制LDPC码编译码算法优化以及应用进行了深入的研究,并取得了一定的研究成果:首先,针对随机构造多进制LDPC码的高编码复杂度,基于线性编码复杂度的迭代编码算法,提出了一种直接构造具有下三角结构的非规则LDPC码的方法—改进的EBF算法/改进的PEG算法,该方案从改进编码方案和构造校验矩阵两方面来降低算法的复杂度,改进构造算法构造的LDPC码字与原构造算法构造的码字相比,可在不损失纠错性能的前提下,极大降低系统的编码复杂度,从而为进一步的硬件实现提供了理论参考。针对代数构造多进制QC-LDPC码算法纠错性能较差的缺陷,及鉴于无线信道的时变特性,提出了一种基于掩盖删余技术构造QC-LDPC码的算法。基于掩盖技术,可以降低硬件实现复杂度以及提高结构构造算法构造的LDPC码字的纠错性能;基于删余技术,可以构造码率自适应的QC-LDPC码,从而提高通信系统的平均有效性。其次,在研究多进制LDPC码译码算法的基础上,提出了一种多进制LDPC码的改进随机译码算法,该译码算法在具有低校验节点及交织运算复杂度同时,可进一步降低变量节点的运算复杂度,同时针对多进制随机译码仅当q≤16时有效的问题,该算法对随机译码算法进行一定的改进,使之可以适用于q16的情况。最后,在研究协作中继通信系统中联合信道编码-网络编码方案的基础上,提出了一种具有低编码复杂度的联合LDPC码-网络编码方案,该方案采用低编码复杂度的校验矩阵构造算法,从而降低整个系统的运算复杂度;该方案不仅具有优异的纠错性能,同时显著提高了系统容量。在研究多进制LDPC码、网络编码的基础上,提出了一种新型的联合信道编码调制-网络编码一体化设计方案,即多进制LDPC码-BICM-网络编码方案。该方案将多进制信道编码调制技术与网络编码技术相结合,译码时考虑到序列的相关性,采用联合迭代相关译码算法,保证系统有效性的同时提高了系统的可靠性。该方案与无中继、信源不相关的多进制LDPC-BICM系统相比,均有着显著的编码增益;且随着相关系数的增加,编码增益的改善越明显。
[Abstract]:When digital information is transmitted in a wireless channel with time-varying characteristics, due to the influence of noise, the receiver can not receive correct information and cause serious influence on people's daily life. Most practical communication systems are based on wireless communication, so how to improve the communication quality of wireless communication needs solutions. It is one of the most important issues to solve the problem, and the application of LDPC code to wireless communication system is an effective measure to solve the problem of wireless communication quality. With the development of communication technology, the continuous development of Internet technology and the increasing demand of high quality multimedia services by users, the future wireless communication technology It must have the ability to provide higher data transmission rates, higher frequency band utilization and higher communication quality services. Therefore, the communication technology used in future wireless communication must meet the high frequency band utilization and high reliability requirements. At this time, the multilevel LDPC code has a more significant advantage compared with the binary LDPC code, but it is highly compiled. The code complexity hinders the process of actual use. Therefore, it optimizes the encoding and decoding algorithm of the multilevel LDPC code and constructs a medium and short code length LDPC code with strong error correction performance. It is important for theoretical analysis and practical application to design the LDPC code modulation integration scheme in high order domain and to study the application of the multilevel LDPC code. In this paper, the optimization and application of LDPC coding and decoding algorithm are studied in this paper, and some research results are obtained. Firstly, a kind of irregular LDPC code with lower trigonometric structure is proposed, which is based on the high coding complexity of random construction of multilevel LDPC codes and the iterative coding algorithm based on the complexity of linear coding. The improved EBF algorithm / improved PEG algorithm, which reduces the complexity of the algorithm from two aspects of improving the coding scheme and constructing the checkout matrix, improves the LDPC codeword constructed by the construction algorithm and the codeword constructed by the original construction algorithm. It can greatly reduce the coding complexity of the system without losing the error correction performance. It provides a theoretical reference for further hardware implementation. In view of the defects in the poor error correction performance of the algebraic structure of the multi band QC-LDPC code algorithm, and in view of the time-varying characteristics of the wireless channel, an algorithm for constructing QC-LDPC codes based on the concealment and deletion technique is proposed. Based on the concealment technology, the complexity of hardware implementation can be reduced and the structure construction can be improved. The algorithm constructs the error correction performance of the LDPC codeword; based on the censoring technique, the code rate adaptive QC-LDPC code can be constructed to improve the average effectiveness of the communication system. Secondly, on the basis of the study of the multilevel LDPC code decoding algorithm, an improved random decoding algorithm for the multilevel LDPC code is proposed. The decoding algorithm has a low checksum node. And the complexity of interlacing operation can further reduce the computational complexity of the variable node. At the same time, the algorithm improves the random decoding algorithm to the case of Q16. At the same time, the algorithm can be applied to the case of the random decoding algorithm. Finally, the joint channel coding network in the research cooperative relay communication system is used. On the basis of the coding scheme, a joint LDPC code network coding scheme with low coding complexity is proposed. The scheme uses a low coding complexity check matrix to construct an algorithm to reduce the computational complexity of the whole system. The scheme not only has excellent error correction performance, but also significantly improves the system capacity. On the basis of LDPC code and network coding, a new integrated channel coding and modulation network coding scheme is proposed, that is, the multi band LDPC code -BICM- network coding scheme. This scheme combines the multi band channel coding modulation technology with the network coding technology, and takes into account the correlation of the sequence in the decoding, and uses the joint iterative correlation. The decoding algorithm ensures the effectiveness of the system while improving the reliability of the system. This scheme has significant coding gain compared with the non relaying and unrelated source LDPC-BICM system, and as the correlation coefficient increases, the improvement of the coding gain is more obvious.

【学位授予单位】：哈尔滨工程大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN911.22

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