Soft-Decision Decoding, Trellis Structure and Coded Modulation

摘要：NCR-9415374，美国。夏威夷的Manoa的“软判决解码、网格结构和编码调制”，PI-Lin：随着对数据完整性的需求增加，用于差错控制的编码在数据传输系统中变得越来越重要。它已成为几乎所有数据通信系统设计中不可或缺的一部分。今天，非常复杂的差错控制编码方案被广泛地用于数据通信系统中以实现可靠的数据传输。本课题的目的是研究编码中的几个问题，这些问题在理论和实践上都很重要。研究内容包括三个相互关联的领域：（1）线性分组码的软判决译码;（2）线性分组码的网格结构;（3）编码调制。 在第一个研究领域中，本研究将设计有效的软判决译码方案，用于线性分组码，以实现最佳或接近最佳的错误性能，降低译码复杂度。所采用的方法包括：（1）基于接收符号的某些可靠性度量的硬判决解码;（2）对硬判决解码字进行迭代再处理，直到获得最佳或接近最佳的差错性能;（3）通过净化网格图搜索待解码码的最大似然解;（4）基于码分解的多级软判决译码。第二部分从状态复杂度、分支复杂度、状态连通度和最小格图的并行结构等方面研究了线性分组码的格结构。对于具有简单网格结构的码，可以应用Viterbi算法以降低计算复杂度来实现最大似然解码。在这一领域中要研究的其他问题包括：（1）为已知码构造最小网格图;（2）在码的比特位置上找到特定的排列，以最小化或降低码网格的结构复杂性;以及（3）状态和分支标记。在第三个研究领域，将继续研究编码调制，以实现带宽有效的通信。调制码的AWGN和衰落信道将被构造和分析。重点放在构造调制码或编码调制系统，以实现高性能，降低解码复杂度。将联合收割机编码调制与乘积编码技术相结合是一种可行的方法。不平等的错误保护调制码也将被调查。本研究的目的是提高编码理论和差错控制技术的知识水平。本研究的丰硕成果将对编码研究和设计有效的差错控制系统以实现可靠的数据通信产生重大影响。*奥布里M.布什计划主任，代理副主任网络和通信研究和网络结构部国家科学基金会

ABSTRACT: NCR-9415374, U. of Hawaii, Manoa, "Soft-Decision Decoding, Trellis Structure and Coded Modulation", PI-Lin: As the demand for data integrity increases, coding for error control becomes increasingly important in data transmission systems. It has become an integral part in almost every data communication system design. Today very sophisticated error control coding schemes are being used in a broad range of data communication systems to achieve reliable data transmission. The objective of this research project is to investigate several problems in coding which are both theoretically and practically important. The research includes three inter-related areas: (1) soft-decision decoding of linear block codes; (2) trellis structure of linear block codes; and (3) coded modulation. In the first research area, the research will devise efficient soft-decision decoding schemes for linear block codes to achieve optimum or near optimum error performance with reduced decoding complexity. The approaches to be taken include: (1) hard-decision decoding based on certain reliability measures of the received symbols; (2) iterative reprocessing of the hard-decision decoded word until optimum or near optimum error performance is achieved; (3) searching for the maximum likelihood solution through a purged trellis diagram for the code to be decoded; and (4) multistage soft-decision decoding based on code decomposition. In the second research area, the trellis structure of linear block codes is investigated in terms of the state complexity, the branch complexity, the state connectivity and parallel structure of minimal trellis diagrams. For codes with simple trellis structure, the Viterbi algorithm can be applied to achieve maximum likelihood decoding with reduced computational complexity. Other problems to be investigated in this area include: (1) construction of minimal trellis diagrams for known codes; (2) finding specific permutations on the bit positions of codes that minimize or reduce the structural complexity of code trellises; and (3) state and branch labeling. In the third research area, the investigation of coded modulation will be continued for bandwidth efficient communications. Modulation codes for both AWGN and fading channels will be constructed and analyzed. Emphasis is placed in constructing modulation codes or coded modulation systems to achieve high performance with reduced decoding complexity. One approach to be taken is to combine coded modulation and product coding technique. Unequal error protection modulation codes will also be investigated. The research is intended to advance the state of knowledge in coding theory and error control techniques. Fruitful results from this study will have significant impact on coding research and the design of efficient error control systems for reliable data communications.*****************************************************************************Aubrey M. BushProgram Director, Acting Deputy Divison DirectorDivision of Networking and Communications Research and InfrastructureNational Science Foundation