Variable-length constrained sequence coding

本文主要研究变长约束序列码在数字传输和存储系统中的持续发展和应用。******数据的编码和解码是所有数字通信系统不可缺少的一部分，包括传输和存储系统。这些编码技术可分为以下几类：******源代码：用于以尽可能紧凑的形式表示源信息；******约束序列（Constrained sequence， CS）码：用于生成满足信道约束的编码符号流，并试图保证实际解调电路的正常运行。******错误控制码：用于检测和纠正解调器错误检测到的符号。******在用源代码压缩数据时，几乎总是使用变长（VL）编码技术，因为它们能够用尽可能少的编码符号有效地表示数据。相比之下，约束序列码和错误控制码的从业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是基于使用VL序列，这使得使用简单有效的VL CS代码成为可能。分组交换传输网络是VL CS代码的首选，使用VL压缩技术的存储系统也是如此。******我的研究将集中在(1)持续发展和(2)用于数字传输和存储系统的可变长度约束序列码的应用。这项工作的起点将是我的小组最近开发的状态无关的VL CS编码技术，它的实现比迄今为止发表的任何其他类型的CS代码更简单，并且提供更高的效率。******对这项令人兴奋的工作的基本性质的扩展将包括：******(1a)扩展当前的状态无关编码技术以支持状态相关编码******(1b)开发最优代码的简化搜索技术******(1c)确定适当的技术以减轻解码期间的错误传播******(1d)优化单词映射以限制VL CS解码期间的错误传播******(1e)将VL CS代码与错误控制代码集成，以及******(1f)将二进制VL CS代码的开发扩展到具有多维信令字母的系统。******我们还将应用这些原则来优化VL CS代码的设计，用于以下重要应用：******(2a)用于闪存的记录代码和******(2b)频谱整形代码，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建有效的约束序列码，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.**