Joint source-channel coding (JSCC) has emerged to be a major field
of research recently. Channel optimized vector quantization (COVQ)
is a simple feasible JSCC scheme introduced for communication over
practical channels.
In this work, we propose an iterative design
algorithm, referred to as the iterative maximum a posteriori (MAP)
decoded (IMD) algorithm, to improve COVQ systems. Based on this
algorithm, we design a COVQ based on symbol MAP hard-decision
demodulation that exploits the non-uniformity of the quantization
indices probability distribution. The IMD design algorithm consists
of a loop which starts by designing a COVQ, obtaining the index
source distribution, updating the discrete memoryless channel (DMC)
according to the achieved index distribution, and redesigning the
COVQ. This loop stops when the point-to-point distortion is
minimized. We consider memoryless Gaussian and Gauss-Markov sources
transmitted over binary phase-shift keying modulated additive white
Gaussian noise (AWGN) and Rayleigh fading channels. Our scheme,
which is shown to have less encoding complexity than conventional
COVQ and less encoding complexity and storage requirements than
soft-decision demodulated (SDD) COVQ systems, is also shown to
provide a notable signal-to-distortion ratio (SDR) gain
over the conventional COVQ designed for hard-decision demodulated
channels while sometimes matching or exceeding the SDD COVQ
performance, especially for higher quantization dimensions and/or
rates.
In addition to our main result, we also propose another
iterative algorithm to design SDD COVQ based on the notion of the
JSCC error exponent. This system is shown to have some gain over
classical SDD COVQ both in terms of the SDR and the
exponent itself. / Thesis (Master, Mathematics & Statistics) -- Queen's University, 2008-08-29 17:58:52.329
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/1390 |
| Date | 04 September 2008 |
| Creators | Ebrahimzadeh Saffar, Hamidreza |
| Contributors | Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Format | 507443 bytes, application/pdf |
| Rights | This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
| Relation | Canadian theses |
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