The use of error-correction coding techniques in communication systems has become
extremely imperative. Due to the heavy constraints faced by systems engineers more
attention has been given to developing codes that converge closer to the Shannon
theoretical limit. Turbo codes exhibit a performance a few tenths of a decibel from the
theoretical limit and has motivated a lot of good research in the channel coding area in
recent years.
In the under-mentioned dissertation, motivated by turbo codes, we study the use of three
new error-correction coding schemes: Repeat-Punctured Superorthogonal Convolutional
Turbo Codes, Dual-Repeat-Punctured Turbo Codes and Dual-Repeat-Punctured
Superorthogonal Convolutional Turbo Codes, applied to the additive white Gaussian noise
channel and the frequency non-selective or flat Rayleigh fading channel. The performance
of turbo codes has been shown to be near the theoretical limit in the AWGN channel. By
using orthogonal signaling, which allows for bandwidth expansion, the performance of the
turbo coding scheme can be improved even further. Since the resultant is a low-rate code,
the code is mainly suitable for spread-spectrum modulation applications. In conventional
turbo codes the frame length is set equal to the interleaver size; however, the codeword
distance spectrum of turbo codes improves with an increasing interleaver size. It has been
reported that the performance of turbo codes can be improved by using repetition and
puncturing. Repeat-punctured turbo codes have shown a significant increase in
performance at moderate to high signal-to-noise ratios. In this thesis, we study the use of
orthogonal signaling and parallel concatenation together with repetition (dual and single)
and puncturing, to improve the performance of the superorthogonal convolutional turbo
code and the conventional turbo code for reliable and effective communications.
During this research, three new coding schemes were adapted from the conventional turbo
code; a method to evaluate the union bounds for the AWGN channel and flat Rayleigh
fading channel was also established together with a technique for the weight-spectrum
evaluation. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2007.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/2306 |
| Date | January 2007 |
| Creators | Pillay, Narushan. |
| Contributors | Xu, Hong-Jun., Takawira, Fambirai. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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