Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"Propagation Measurements"”.
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Wideband propagation measurements for personal communication systems
The propagation channel is a vital but invisible part of any wireless communications system. As wavelengths get shorter, multipath effects become more pronounced, causing small scale fading in narrowband channels, and inter-symbol interference in wideband systems because of delay spread in the …
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Radio Wave Propagation Measurements and Modeling for Land Mobile Satellite Systems
… is conditioned by the characteristics of the propagation path between a satellite and mobile users. The most important propagation effect in land mobile satellite system is roadside attenuation of the signals due to vegetation or urban structures. System designers should have the most reliable …
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Indoor wide band radio wave propagation measurements and models at 1.3 ghz and 4.0 ghz
An extensive radio wave propagation measurement campaign was conducted at 1.3 GHz and 4.0 GHz inside four buildings, including a sports arena, a modern closed-plan office building, and two dissimilar, open-plan factories. Measurements were recorded at 57 locations using base station antenna heights …
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Wideband Propagation Measurement Results, Simulation Models, and Processing Techniques for a Sliding Correlator Measurement System
Radio wave propagation measurements provide a way to accurately and reliably characterize environments to assist in the development and optimization of wireless communication systems. As digital radio systems occupy wider bandwidths and use multipath signal combining to enhance quality of service, …
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A Study of Indoor Ultra-wideband Propagation Measurement and Characterization
… large amount of data to characterize the propagation behavior of UWB signals in indoor environments and develop accurate channel models. This thesis focuses primarily on a frequency-domain approach for propagation measurements and characterization of indoor UWB channels. This approach is …
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Multiple input multiple output channel measurements and system performance
… are designed and deployed, a database of typical propagation measurements is required to confirm theoretical predictions with reality. The design, development and use of specialised measurement equipment to accurately establish an indoor MIMO measurement database is presented in this thesis.
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High frequency acoustic propagation and modeling in stratified estuaries
Acoustic propagation measurements are made in a highly variable and stratified estuary using high frequency transducers (120kHz) on tripods placed across the main channel of the river flow. The measurements are taken in the Connecticut River across several tidal cycles, when the flood tide causes a …
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Effects of the troposphere upon radio communications and implications for weather measurement
… of Very High Frequency (VHF) radio wave propagation to estimate the refractive index of air over a propagation path and subsequently the pressure, temperature, and water vapour. This can be accomplished by transmitting a known signal from one spatial location to another, and accurately …
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High Frequency Acoustic Propagation and Modeling in Stratified Estuaries
Acoustic propagation measurements are made in a highly variable and stratified estuary using high frequency transducers (120kHz) on tripods placed across the main channel of the river flow. The measurements are taken in the Connecticut River across several tidal cycles, when the flood tide causes a …
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A Technique for Evaluating the Uncertainties in Path Loss Predictions Caused by Sparsely Sampled Terrain Data
Radio propagation models provide an estimate of the power loss in a communication link caused by the surface of the ground, atmospheric refraction, foliage, and other environmental factors. Many of the models rely on digital topographic databases to provide information about the terrain, and …
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Performance Evaluation of DECT in Different Radio Environments
… in a radio channel, channel impulse response measurements at 1.9 GHz are made. Parameters that help describe the radio channel are identified and calculated from the recorded power delay profile measurements. Finally, a mean-opinion-score (MOS) rating was performed for National Semiconductor …
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Antenna Array Systems: Propagation and Performance
… of future systems. This report focuses on signal propagation modeling for antenna array systems and on its relationship to the performance of these systems. Accurate simulation and analytical models are prerequisite to the characterization of antenna array system performance. Finally, an …
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Studies on the dynamics of limited filaments
… vacuum chamber walls. The theories of filament propagation are based on a circuit model of current closure loops within the filament and are described herein. Two experimental configurations based on different modes of filament generation are utilized in the Versatile Toroidal Facility (VTF) to …
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Propagation prediction for PCS design in urban microwave channels
… problems which can be avoided with extensive propagation studies in both measurements and predictions. Currently, there is no readily available tool to predict propagation channels for the small coverage area that PCS operates at 1900 MHz. This thesis presents new methods for propagation …
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Enhancing Nonlinear Ultrasonic Methods for Laboratory and Clinical Applications
… associated with nonlinear ultrasonic field propagation, measurements of the nonlinear properties of materials, and mechanisms contributing to the observed systematic variation of backscattered ultrasonic energy from the heart over the heart cycle. Studies were performed to address the …
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Low frequency indoor radiolocation
… concerns the application of electromagnetic wave propagation to the problem of indoor radiolocation. Determining the location of people and objects relative to their environment is crucial for asset tracking, security, and human-computer interface (HCI) applications. These applications may be as …
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Interference Control of Indoor Cognitive Radio Systems
… assessed through simulations in which realistic propagation scenarios are considered, e.g. when internal partition walls and multipath fading are present. Mixed indoor/outdoor propagation measurements have also been conducted to con rm the applicability of the COST-231 building penetration model, …
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The Impact of Signal Bandwidth on Indoor Wireless Systems in Dense Multipath Environments
… sensitive to the degrading effects of multipath propagation. By reducing the sensitivity to multipath, more robust and higher capacity systems can be realized. However, as signal bandwidth is increased, the complexity of a Rake receiver (or other receiver structure) required to capture the …
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Characterization of Ultra Wideband Communication Channels
… have not yet been thoroughly investigated. The propagation of UWB signals in indoor environments is the single most important issue with significant impacts on the future direction, scope, and generally the extent of the success of UWB technology. The objective of this dissertation is to obtain …
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Measured and Modeled Time and Angle Dispersion Characteristics of the 1.8 GHz Peer-to-Peer Radio Channel
In an extensive outdoor propagation study, low antenna heights of 1.7 m are used at both the transmitter and the receiver to measure over 3500 wideband power-delay profiles (PDPs) of the channel for a peer-to-peer communications system. Rural and urban areas are studied in 22 different …
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