CIF: Small: Collaborative Research: New Approaches to the Design of Joint Source-Channel Codes

信源-信道联合编码和解码技术正在迅速崛起，成为多媒体革命基础上的复杂性和延迟受限传输系统的重要设计工具。在这种情况下，与完全分离信源和信道编码功能的系统相比，这些技术具有以更小的复杂性或延迟提供相同性能的潜力。研究人员通过研究某些类型的最佳可变长度纠错码及其在网络中的应用，发展了对联合信源-信道码构造的理论见解和实用方法。通过这些研究获得的见解促进了新的高级编码策略以及指导未来无线和多媒体系统设计的基本理论。联合信源-信道编码的一种方法是考虑前缀条件码，该前缀条件码具有固有的信源压缩属性并且另外能够检测或纠正由通信信道上的噪声引起的差错。因此，这些码通常需要比经典信道码更小的冗余量来实现相同的容错量。然而，目前对这些代码的理解仍然相当有限，这导致研究人员将重点放在启发式上。研究人员通过从三个相互关联的方向解决研究问题来解决这些问题。具体地说，我们(1)开发了具有内在容错性的新的最小冗余变长码，并研究了与其设计和压缩性能相关的问题；(2)研究了这类码在传感器网络和自组织网络中的应用，并深入了解了它们对更高通信层的影响；(3)研究了可逆变长码的构造，包括那些具有特殊纠错特性的可逆变长码。

Joint source-channel coding and decoding techniques are rapidly emerging as important design tools for the complexity- and latency-constrained transmission systems that underlie the multimedia revolution. In such scenarios these techniques have the potential to offer the same performance with less complexity or delay compared with systems which completely separate the source and channel coding functions. The investigators develop theoretical insights and practical approaches into the construction of joint source-channel codes by addressing certain classes of optimal variable-length error correcting codes and their application to networks. The insights gained by these studies facilitates new advanced coding strategies as well as a fundamental theory that guides the design of future wireless and multimedia systems. One approach to joint source-channel coding is to consider prefix condition codes which have an inherent source compression property and are in addition able to detect or correct errors resulting from noise on the communication channel. Thus, these codes typically require a smaller amount of redundancy than classical channel codes to achieve the same amount of error resilience. However, the current understanding of these codes remains rather limited which has led researchers to focus on heuristics. The investigators address these issues by tackling research problems in three interrelated directions. In particular, we (1) develop new minimum-redundancy variable-length codes with inherent error resilience properties and investigate issues related to their design and compression performance; (2) study the application of this family of codes to sensor and ad hoc networks and gain insight into their repercussions for higher communication layers; (3) investigate the construction of reversible variable-length codes including those with special error-correcting properties.