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 27 for “"LMDS"”.
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Adaptive Digital Predistortion with Applications for LMDS Systems
A limiting factor in the widespread deployment of LMDS systems is the limited distance of current systems. Rain attenuation and limited transmitter power are the primary causes of the limited distance. Adaptive digital predistortion is presented as a method of increasing effective transmitter …
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A Proposed Architecture for a High-Data Rate Mobile Lmds Network
… mobile Local Multipoint Distribution Service (LMDS) Network. Its goal is to provide a workable "strawman" design that can serve as a basis for further research. The architecture is designed to offer broadband services to train commuters via LMDS. The thesis provides a broad overview of system …
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System Performance of an Over-Water Propagation for an LMDS Link
… of Local Multipoint Distribution Service (LMDS) will eventually outweigh those of its current competitors in the wired market. Since the rural communities will reap the most benefits from this technology due to its low costs, studies on the channel behavior and terrain relationships must be …
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A Study of Rough Surface Scattering Phenomena in the LMDS Band (28 GHz)
… scattering phenomena were investigated in the LMDS band (28 GHz). We used the newly developed sampling swept time delay short pulse (SSTDSP) sounder to collect field data in certain locations on the Virginia Tech campus. The sounder collected the channel impulse response analog waveform, …
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Factors Affecting Deployment Strategies for an LMDS System in a Rural Commercial Environment
… Local Multipoint Distribution Service (LMDS) technology as a major contender in the race to provide broadband connectivity to customers. With the focus on solving the "Last Mile" problem, LMDS provides a significant reduction in both the time it takes for system deployment as well as the …
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Design and Implementation of a Swept Time Delay Short Pulse (SSTDSP) Wireless Channel Sounder for LMDS
… point high data rate applications in the 28 GHz LMDS band at a fraction of the cost and complexity of existing wideband channel sounders. The SSTDSP sounder monitors the behavior of the LMDS channel by sampling the impulse response of the channel in real time. This digitized impulse response is …
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Adaptive Protocols to Improve TCP/IP Performance in an LMDS Network using a Broadband Channel Sounder
Virginia Tech researchers have developed a broadband channel sounder that can measure channel quality while a wireless network is in operation. Channel measurements from the broadband sounder hold the promise of improving TCP/IP performance by trigging configuration changes in an adaptive data link …
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An Introduction to Local Multipoint Distribution Services with an Investigation of the Effects of Vegetation on the Radio Channel
… to Local Multi-point Distribution Services (LMDS). The reader will first learn what LMDS is and then review the system architectures that are made available for LMDS technologies. After summarizing the basics of LMDS, we will compare it with some competing technologies. The reader will then …
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The System Design of a Global Communications System for Military and Commercial use Utilizing High Altitude Unmanned Aerial Vehicles (UAVs) and Terrestrial Local Multipoint Distribution Service (LMDS) Sites
This thesis proposes the design of the UAV-LMDS communication system for military and commercial use. The UAV-LMDS system is a digital, wireless communication system that provides service using unmanned aerial vehicles (UAVs) flying at 60,000 ft. acting as communication hubs. This thesis provides …
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A Framework for policy-based Quality of Service for fixed broadband wireless networks
… for the Local Multipoint Distribution Service (LMDS) wireless network in Blacksburg, Virginia is described in detail. The focus of the research work was to enable simpler management of the LMDS system and to design and enable network QoS. The thesis examines various means to provide QoS in the …
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Simulation Study of Local Multipoint Distribution Service
… for Local Multipoint Distribution Service (LMDS) systems, and uses simulation to examine the performance of two different multiple access schemes and two different duplexing schemes. LMDS is a broadband wireless point-to-multipoint access network that aims to improve network access capacity …
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System Design of an Integrated Terrestrial-Satellite Communications Network for Disaster Recovery
… terrestrial Local Multiple Distribution Service (LMDS) system and a Ka-band satellite system, and potentially being able to provide as an additional Ka-band satellite network backbone to the Virginia Tech terrestrial LMDS system for better and faster communications deployments. The Spaceway …
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Stochastic propagation and planning models for broadband fixed wireless access links
… Local Multipoint Distribution Systems (LMDS), are increasingly being regarded as a legitimate challenger to cable and digital subscriber lines (DSL), particularly in markets with poor cable or copper infrastructure. These systems have capabilities that go beyond the current WiFi and …
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Wideband Terrestrial Path Loss Measurement Results For Characterization of Pico-cell Radio Links at 38 GHz and 60 GHz Bands of Frequencies
… 2004 and Local Multipoint Distribution Services (LMDS) have enormous potential to emerge as the most reliable and cost-effective solution. However, in order to design and deploy LMDS systems, it is vital for system designers to be able to predict the behavior of mm-waves (28, 38 and 60GHz) during …
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Contribución al estudio de la viabilidad de operadores de telecomunicaciones de acceso inalámbrico fijo mediante el desarrollo de escenarios tecno-económicos
… radio por los operadores del servicio fijo (LMDS, WiFi o WiMAX) de forma que los resultados históricos permitan contrastar la bondad del modelo y poder así estimar la viabilidad de nuevas opciones de negocio.
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Characterization and Evaluation of Non-Line-of-Sight Paths for Fixed Broadband Wireless Communications
… of specular multipath and diffuse scattering at LMDS frequencies. An algorithm is presented that estimates link performance based on the channel impulse response. Presented and analyzed are representative impulse responses (one is primarily specular in nature and one shows significant diffuse …
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Terrestrial radio wave propagation at millimeter-wave frequencies
… for Local Multipoint Distribution Services (LMDS). Wideband measurements are taken on three cross-campus links at Virginia Tech. The goal is to determine weather effects on the wideband channel properties. The measurement results include multipath dispersion, short-term variation and signal …
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Configurable Architecture for System-Level Prototyping of High-Speed Embedded Wireless Communication Systems
… of a Local Multipoint Distribution Service (LMDS) gateway for a disaster response network. The design of the gateway posed several challenges due to high data rates (120 Mbits/sec) and adaptive features like variable Forward Error Correction Coding and optional link-level retransmissions. The …
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Simulation Tool and Metric for Evaluating Wireless Digital Video Systems
… (Digital Audio-Visual Council) layout for the LMDS (Local Multipoint Distribution Service) system and includes several error control algorithms and a packetizing algorithm that is MPEG-compliant. This work introduces a statistical approach to monitoring the video quality. The …
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Silicon-based Microwave/Millimeter-wave Monolithic Power Amplifiers
… radar and local multipoint distribution system (LMDS). Although there has been a significant increase in silicon-based implementations recently, this area still has significant need for research and development. For example, one microwave/mm-wave front-end component that has seen little …
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