Date of Award

6-2000

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Electrical and Computer Engineering

First Advisor

Richard A. Raines, PhD

Abstract

Research in coding theory has seen many proposals aimed at the construction of powerful codes using block and convolutional codes. Recently, a new forward error control code, known as turbo code, was introduced. This new code yields very good performance (near the Shannon limit) with relatively simple component codes and large interleavers in combination with an iterative decoding process. Among the most important applications of turbo codes are wireless mobile communication systems. A significant performance metric for this application is the minimization of end-to-end delay. In this dissertation, different ways to enhance the performance of turbo codes with short frames are presented. One way of enhancing the performance of turbo codes with short frames is by optimizing the energy allocation strategies to the output bitstreams. For turbo codes with short frames, different ways to allocate the energy are investigated using computer simulation and modified analytic bounds. The results show that the performance is improved without any increase in complexity. Another way to enhance the performance is with the proper design of the interleaver. This work proposes a new and unique interleaver for equal and unequal error protections. In equal error protection applications, the proposed interleaver performance outperforms the other conventional interleavers at higher signal-to-noise ratios. The introduction of this interleaver allows for less complex hardware implementations as the single interleaver replaces multiple interleavers performing the task.

AFIT Designator

AFIT-DS-ENG-00-01

DTIC Accession Number

ADA380931

Comments

The author's Vita page is omitted.

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