CAREER: Design and Analysis of Iteratively Decodable Codes for Wireless Communications and Digital Magnetic Recording

下一代无线系统和数据存储系统肯定会利用编码理论和信号处理的最新发展。在过去的十年中，串联编码和迭代处理已经成为编码理论和信号处理的强大范例。无线通信和磁记录系统都有特殊的约束和限制。在无线通信中，保持高功率和频谱效率是关键。此外，在某些系统中，可能需要为所传输的信号保持恒定的包络。数字磁记录系统可以容忍很少的冗余和要求非常低的端到端误码率。对于在这些系统中使用的串联编码和迭代处理的潜力和局限性的理解是至关重要的。虽然使用迭代解码对串联代码进行精确分析是困难的，但最近提出的一种称为密度进化的技术是一种强大的工具，它允许对迭代解码进行分析，并提供相当大的洞察力。利用这种技术或其变体，本研究旨在进一步设计和分析应用于无线通信系统和数字磁记录系统的迭代可解码代码。本研究强调了两个主要思想：不规则码和匹配迭代译码的码设计。基于这些思想，我们将讨论三个具体领域。它们是：1)设计和分析不规则的并行和串行级联码，包括非二进制码和不规则的turbo栅格编码调制；2)综合研究具有内存的调制器（如CPM）的级联编解码策略，以及它们在AWGN、平坦瑞利衰落和码间干扰信道中的性能分析；3)数字磁记录码的设计和分析——特别强调在外部里德-所罗门码存在的情况下的连接码的设计，评估新颖的高速率码和当总体期望误码率为10^{-15}时的低复杂度接收器结构。

Future generation wireless systems and data storage systems will certainly take advantage of the recent developments in coding theory and signal processing. In the last decade, concatenated coding and iterative processing have emerged as powerful paradigms in coding theory and signal processing. Both wireless communications and magnetic recording systems place particular constraints and limitations. In wireless communications, maintaining high power and spectral efficiency is key. In addition, in some systems, it may be necessary to maintain a constant envelope for the transmitted signals. Digital magnetic recording systems can tolerate very little redundancy and require very low end to end bit error rates. It is crucial to develop an understanding of the potential and limitations of concatenated coding and iterative processingfor use in these systems. While exact analysis of concatenated codes with iterative decoding is difficult, a recently proposed technique called density evolution is a powerful tool that permits analysis of iterative decoding and offers considerable insight. Using this technique or, a variation thereof, this research aims at furthering the design and analysis of iteratively decodable codes with applications to wireless communications systems and digital magnetic recordingsystems.This research emphasizes two main ideas - irregular codes and the design of codes matched to iterative decoding. Based on these ideas, three specific areas are addressed. They are 1) Design and analysis of irregular parallel and serial concatenated codes including non-binary codes and irregular turbo trellis coded modulation, 2) A comprehensive study of concatenated coding and decoding strategies for modulators with memory (such as CPM), their performance analysis for AWGN, flat Rayleigh fading and inter-symbol interference channels, 3) Design and analysis of codes for digital magnetic recording - particular emphasis is given to the design of concatenated codes in the presence of an outer Reed-Solomon code, evaluating novelhigh rate codes and on low complexity receiver structures when the overall desired bit error rates are of the order of 10^{-15}.