Collaborative Research - New Directions in Turbo Coding

本研究涉及数字通信和存储系统的差错控制编码的一般领域。 特别是，它描述了一些基本的研究课题有关的一个强大的新方法的错误控制编码称为涡轮编码。 该研究有两个主要目标：（1）提出新的Turbo编码方案的性能和/或复杂度的优势相比，目前的最先进的，和（2）推进知识的基本状态，关于这个令人兴奋的新方法的错误控制编码。 虽然仍然非常新，但turbo编码开始应用于需要差错控制技术的许多领域，包括深空通信、卫星通信和数字蜂窝电话，仅举几例。 由于它能够以合理的实现复杂度接近理论极限，可以预期，在未来10年左右，Turbo编码和相关技术将对几乎所有的差错控制编码应用产生巨大的影响。Turbo编码可以在非常接近信道容量的信噪比下实现中等的比特差错率（在10-4到10-6的范围内）。 然而，Turbo编码性能仍有改进的空间，特别是在要求误码率低于10-6的应用中。 此外，人们对更完整地基本了解导致如此优异性能的涡轮码的关键属性有着相当大的理论兴趣。 研究者们对Turbo码中的几个新的基础研究问题进行了研究。其中要研究的主题是（1）几种新的Turbo码设计，其能够实现比现有方案更好的性能，（2）引入更一般的Turbo码类别，其与标准Turbo编码方法相比具有产生更好的代码和/或降低解码复杂度的潜力，以及（3）开发新的次优软输入，- 软输出解码方法，其可以与更多的码一起使用，从而在非常低的误码率（比如低于10-10）下提供接近容量性能的承诺。

ABSTRACTThis research involves the general area of error control coding for digital communication and storage systems. In particular, it describes a number of fundamental research topics related to a powerful new method of error control coding called turbo coding. The research has two major goals: (1) to propose new turbo coding schemes with performance and/or complexity advantages compared to the current state-of-the-art, and (2) to advance the fundamental state of knowledge regarding this exciting new approach to error control coding. Although still very new, turbo coding is beginning to be applied in numerous areas that require error control techniques, including deep space communication, satellite communication, and digital cellular telephony, to name just a few. Because of its ability to perform close to theoretical limits with reasonable implementation complexity, it is anticipated that turbo coding and related techniques will have an enormous impact on virtually all applications of error control coding over the next 10 years or so.Turbo coding can achieve moderate bit error rates (in the range of 10-4 to 10-6) at signal-to-noise ratios very close to channel capacity. However, there is still room for improvement in turbo coding performance, particularly in applications that require bit error rates below 10-6. Further, there is considerable theoretical interest in achieving a more complete fundamental understanding of the key properties of turbo codes that result in such excellent performance. The investigators study several new basic research problems in turbo coding. Among the topics to be investigated are (1) several new turbo code designs capable of achieving even better performance than existing schemes, (2) the introduction of a more general class of turbo codes that has the potential to yield better codes and/or reduced decoding complexity compared to standard turbo coding methods, and (3) the development of a new sub-optimum soft-in, soft-out decoding approach that can be used with more codes, thus offering the promise of near capacity performance at very low bit error rates, say below 10-10.