Concatenated codes for cellular spread spectrum and wide band mobile radio communication systems /
In a wideband mobile radio communication system, multipath effects within the channel introduce fading, doppler shifts and frequency selectivity - each of these impairments degrades the bit-error rate performance of the communication system. This study focuses upon the use of a turbo error correctio...
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1999.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=731681731&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | In a wideband mobile radio communication system, multipath effects within the channel introduce fading, doppler shifts and frequency selectivity - each of these impairments degrades the bit-error rate performance of the communication system. This study focuses upon the use of a turbo error correction system within a wideband mobile radio communications environment to improve bit-error rate performance. Because of decoding time delay constraints, the turbo codes under study are designed to impose limited decoding delay. Under the restriction that neither a large number of decoding iterations, nor a large turbo code interleaved are allowable, we simulate the bit-error rate performance of our turbo error correction system within a mobile radio system. By simulations we determine the penalty that fading, doppler shifts and frequency selectivity levy upon the bit-error rate performance of a turbo code operating in multipath fading subject to delay constraints typical of speech and short frame data in cellular spread spectrum and wide band mobile radio communication systems. Here we observe that for the case of hat fading, turbo codes constrained to short interleaving yield acceptable performance without imposing large decoding delay. For frequency selective fading channels, intersymbol interference distortion causes even more severe degradation in bit-error rate performance than in the flat fading case. Iterative equalization and decoding is shown to perform very well on a frequency selective fading channel; however, it is critical that we choose a sufficiently large turbo code interleaved in order to both mitigate intersymbol interference and capitalize on the large coding gains that make turbo codes so exciting. |
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| Item Description: | Vita. "Major Subject: Electrical Engineering". |
| Physical Description: | xi, 78 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 51-53). |