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Iterative Decoding and Channel Estimation over Hidden Markov Fading Channels

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dc.contributor.authorKhan, Anwer Alien
dc.contributor.committeechairEbel, William J.en
dc.contributor.committeememberTranter, William H.en
dc.contributor.committeememberGray, Festus Gailen
dc.contributor.committeememberBostian, Charles W.en
dc.contributor.departmentElectrical and Computer Engineeringen
dc.date.accessioned2014-03-14T20:35:57Zen
dc.date.adate2000-05-24en
dc.date.available2014-03-14T20:35:57Zen
dc.date.issued2000-05-03en
dc.date.rdate2001-05-24en
dc.date.sdate2000-05-10en
dc.description.abstractSince the 1950s, hidden Markov models (HMMS) have seen widespread use in electrical engineering. Foremost has been their use in speech processing, pattern recognition, artificial intelligence, queuing theory, and communications theory. However, recent years have witnessed a renaissance in the application of HMMs to the analysis and simulation of digital communication systems. Typical applications have included signal estimation, frequency tracking, equalization, burst error characterization, and transmit power control. Of special significance to this thesis, however, has been the use of HMMs to model fading channels typical of wireless communications. This variegated use of HMMs is fueled by their ability to model time-varying systems with memory, their ability to yield closed form solutions to otherwise intractable analytic problems, and their ability to help facilitate simple hardware and/or software based implementations of simulation test-beds. The aim of this thesis is to employ and exploit hidden Markov fading models within an iterative (turbo) decoding framework. Of particular importance is the problem of channel estimation, which is vital for realizing the large coding gains inherent in turbo coded schemes. This thesis shows that a Markov fading channel (MFC) can be conceptualized as a trellis, and that the transmission of a sequence over a MFC can be viewed as a trellis encoding process much like convolutional encoding. The thesis demonstrates that either maximum likelihood sequence estimation (MLSE) algorithms or maximum <I> a posteriori</I> (MAP) algorithms operating over the trellis defined by the MFC can be used for channel estimation. Furthermore, the thesis illustrates sequential and decision-directed techniques for using the aforementioned trellis based channel estimators <I>en masse</I> with an iterative decoder.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-05102000-13390004en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05102000-13390004/en
dc.identifier.urihttp://hdl.handle.net/10919/32470en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartAAKhan.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectTrellis Decodingen
dc.subjectHidden Markov Modelsen
dc.subjectIterative Decodingen
dc.subjectChannel Estimationen
dc.subjectTurbo Codesen
dc.subjectBaum-Welch Algorithmen
dc.subjectFading Chanelsen
dc.titleIterative Decoding and Channel Estimation over Hidden Markov Fading Channelsen
dc.typeThesisen
thesis.degree.disciplineElectrical and Computer Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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