Turbo codes are a class of forward error correction (FEC) codes that offer energy
efficiencies close to the limits predicted by information theory. The features of turbo
codes include parallel code concatenation, recursive convolutional encoding, nonuniform
interleaving, and an associated iterative decoding algorithm. The excellent performance
of turbo codes explains why much of the current research is focused on applying turbo
codes to different systems.
This dissertation first outlines a new simple criterion for stopping the iterative process of
the turbo decoder for each individual frame immediately after the bits are correctly
estimated and thus prevents unnecessary computations and decoding delay.
The dissertation then considers the performance of turbo coded DS-CDMA systems. The
performance analysis begins with simulation results for turbo coded DS-CDMA over a
multi-path Rayleigh fading channel. The channel is then modeled using the Gilbert-Elliott
channel model and analytical expressions for the performance of the system are derived.
The influence of various parameters such as the Doppler frequency, the signal-to-noise
ratio threshold on the system performance are analyzed and investigated. / Thesis (M.Sc.Eng)-University of Natal, Durban, 2001.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/8993 |
| Date | January 2001 |
| Creators | Nkouatchah, Telex Magloire Ngatched. |
| Contributors | Takawira, Fambirai. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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