Collaborative Research - New Directions in Turbo Coding

Ohio State University Research Foundation -Do Not Use, Columbus OH

Investigators

Abstract

ABSTRACT This 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.