Synchronization issues regarding the meteor burst communication channel.
Item
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Title
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Synchronization issues regarding the meteor burst communication channel.
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Identifier
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AAI9119665
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identifier
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9119665
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Creator
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Parsa, Kourosh.
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Contributor
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Adviser: D. L. Schilling
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Date
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1991
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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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Engineering, Electronics and Electrical
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Abstract
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Interest in high-throughput, high-speed digital communications using the meteor scatter channel has necessitated detailed studies of the channel multipath structure and the phase perturbations, primarily because a coherent modem's performance is dependent on timing and phase jitter. The coherent demodulation process entails two key functions: (1) clock recovery by the bit synchronizer, and (2) phase and frequency acquisition and tracking by the carrier recovery circuit. Timing jitter is a measure of the accuracy of the recovered clock, whereas phase jitter corresponds to a phase offset (error) in estimating the phase of the recovered carrier. Multipath spread is the source of timing uncertainty, which in turn effects the timing jitter suffered by the bit synchronizer in the coherent receiver.;In the first part of this study, a new MB channel model is developed. This is achieved by characterizing the MB doppler spread, doppler rate, head-echo induced phase jitter, and deriving new and simple mathematical expressions for them. The new MB channel model lays the foundation for developing high data-rate adaptive systems, and permit waveform coding and design for the band-limited meteor burst channel to be systematically approached and resolved, as well as can function as a basis of comparison for the performance of various modulation-coding schemes.;In the second part of this study, the new MB channel model is used to investigate the feasibility of building high-speed adaptive coherent modems. To do so, we compute the phase and timing jitter at a typical adaptive coherent receiver. A jitter loss formula is then derived which expresses the SNR penalty as a function of timing and phase offsets for MPSK. The jitter loss is then incorporated into the MB communication system's throughput performance, and finally a maximum-bits-per-burst bound is derived for a sample system. It is shown that MB channel impairments can cause an effective 46% reduction in the average data rate (throughput) for the given adaptive coherent modem and the sample system.
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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.
