Variable-length constrained sequence coding

本研究致力于在数字传输和存储系统中继续开发和应用可变长度约束序列码。数据的编解码是所有数字通信系统中不可或缺的一部分，包括传输和存储系统。这些编码技术分为以下几类：*源代码：用于以尽可能紧凑的形式表示源信息；*约束序列(CS)码：用于生成满足信道约束的编码符号流，并尝试确保实际解调电路的正确操作，以及*差错控制码：用于检测和纠正已被解调器错误检测的符号。*当使用源代码压缩数据时，可变长度(VL)编码技术几乎总是被使用，因为它们能够用尽可能少的编码符号有效地表示数据。相反，受限序列码和差错控制码两者的实践者继续关注固定速率码的开发和实现。然而，许多新的通信系统本质上基于VL序列的使用，这使得能够使用简单和有效的VL CS码。分组交换传输网络和使用VL压缩技术的存储系统都是VL CS码的主要候选者。*我的研究将集中在(1)数字传输和存储系统中可变长度约束序列码的继续开发和应用。这项工作的起点将是我的团队最近开发的与状态无关的VL CS编码技术，其实现更简单，并提供更高的效率，*对这项激动人心的工作的基本性质的扩展将包括：*(1a)扩展当前的独立于状态的编码技术以支持依赖于状态的编码*(1b)开发用于最优码的简化搜索技术*(1c)确定适当的技术以减轻解码期间的错误传播*(1d)优化字映射以限制在VL CS解码期间的错误传播*(1e)集成VL CS码与差错控制码，和*(1f)将二进制VL CS码的开发扩展到具有多维信令字母表的系统。*我们还将应用这些原则来优化VL CS码的设计，用于以下重要应用：*(2a)闪存记录码，和*(2b)频谱整形码，以避免单载波数字视频传输系统中的窄带干扰。*因此，本研究将继续开发一种新的方法来构造有效的约束序列码，并将展示它们在新的和不断发展的数字通信系统中的设计和应用。

This research focuses on the continued development and application of variable-length constrained sequence codes in digital transmission and storage systems.******Encoding and decoding of data is an indispensable part of all digital communication systems, including both transmission and storage systems. These coding techniques fall into the general classes of:******Source codes: used to represent the source information in as compact a form as possible;******Constrained sequence (CS) codes: used to generate encoded symbol streams that satisfy the constraints of the channel and attempt to ensure proper operation of practical demodulation circuitry, and******Error control codes: used to detect and correct symbols that have been incorrectly detected by the demodulator.******When compressing data with a source code, variable-length (VL) coding techniques are almost always used owing to their ability to efficiently represent the data with as few encoded symbols as possible. In contrast, practitioners of both constrained sequence codes and error control codes continue to focus on the development and implementation of fixed-rate codes.******However, many new communication systems are inherently based on the use of VL sequences which enables the use of simple and efficient VL CS codes. Packet-switched transmission networks are prime candidates for VL CS codes, as are storage systems that use VL compression techniques.******My research will focus on (1) the continued development of and (2) the application of variable-length constrained sequence codes for digital transmission and storage systems. The starting point of this work will be the state-independent VL CS coding technique recently developed in my group whose implementation is simpler, and which offers higher efficiency, than any other class of CS codes published to date.******Extensions of a fundamental nature to this exciting work will include:******(1a) extending the current state-independent coding techniques to support state-dependent encoding******(1b) developing simplified search technique for optimal codes******(1c) determining appropriate techniques to mitigate error propagation during decoding******(1d) optimizing word mappings to limit error propagation during VL CS decoding******(1e) integrating VL CS codes with error control codes, and******(1f) extending the development of binary VL CS codes to systems with multidimensional signaling alphabets.******We will also apply these principles to optimize the design of VL CS codes for the important applications of:******(2a) recording codes for flash memory, and******(2b) spectral shaping codes to avoid narrowband interference in single-carrier digital video transmission systems.******This research will therefore continue the development of a new approach to construct efficient constrained sequence codes and will demonstrate their design and application in new and evolving digital communication systems.**