Trellis encoding for quadrature amplitude modulation clusters for primary rate integrated services digital network.
Item
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Title
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Trellis encoding for quadrature amplitude modulation clusters for primary rate integrated services digital network.
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Identifier
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AAI9315479
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identifier
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9315479
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Creator
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Khalifa, Ahmed Mohamed Rashad.
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Contributor
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Adviser: Syed V. Ahamed
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Date
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1993
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Language
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English
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Publisher
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City University of New York.
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Subject
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Computer Science
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Abstract
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Trellis-coded modulation has evolved over the past decade as a combined coding and modulation technique for digital transmission over bandlimited channels. Its main attraction comes from the fact that it allows the accomplishment of significant coding gains over conventional uncoded multilevel modulation without compromising bandwidth efficiency. Trellis schemes utilize redundant nonbinary modulation in combination with a finite-state encoder, which controls the selection of modulation signals to generate coded alphabet sequences. It became necessary to study the implementation of these coding techniques on a typical loop environment to enhance the transmission rate to the Primary Rate ISDN (PR-ISDN).;This dissertation studies the effect of trellis encoding algorithms, and evaluates the effect of system components, such as echo cancelers, in a practical and existing Carrier Serving Area (CSA) loop environment.;The basic methodology for the simulation of trellis codes for QAM clusters is developed and utilized. The loop topologies are discussed. For three sample loops, the effect of trellis codes for 16- and 64-QAM is studied. The coded 16- and 64-QAM constellations for the three sample loops under various echo cancellations (55, 60, 65, 70, and 75 dB) are presented. The effect of trellis codes on the entire CSA is also presented. The average noise in both constellations is presented for the different echo cancellation values. The coding gains for each sample loop are presented under various conditions using coded 16- and 64-QAM with respect to the uncoded 8-PSK and 32-CROSS, respectively. A comparison between the coded schemes (16- & 64-QAM) and the uncoded schemes (16- & 64-QAM) is discussed at 60 dB echo cancellation. The loops that fail to carry the PR-ISDN at 60 dB echo cancellation are tabulated for the coded and uncoded schemes. The findings presented in this dissertation have not been published for any trellis coding techniques in loop environments.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
