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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Caching-based Multipath Routing in Mobile Ad Hoc Networks

Joshi, Vineet 21 April 2009 (has links)
No description available.
92

CHARACTERIZATION OF GLOBAL POSITIONING SYSTEM EARTH SURFACE MULTIPATH AND CROSS CORRELATION FOR AIRCRAFT PRECISION APPROACH OPERATIONS USING SOFTWARE RADIO TECHNOLOGY

Zhu, Zhen 13 October 2006 (has links)
No description available.
93

Fading multipath bias errors in global positioning system receiver tracking loops

Kelly, Joseph Michael January 2001 (has links)
No description available.
94

A mathematical model to aid in the design of ameliorating cosmetics for conducting surfaces that ordinarily produce derogative multipath for the ILS localizer course

Odunaiya, Simbo Ajayi January 1995 (has links)
No description available.
95

Development and verification of a mathematical model to investigate the effects of earth-surface-based multipath reflections at a differential global positioning system ground reference site

Aloi, Daniel Nicholas January 1999 (has links)
No description available.
96

A comparative study of advanced multipath mitigating global positioning system receiver architectures

Kalyanaraman, Sai K. January 1999 (has links)
No description available.
97

Joint time frequency analysis of Global Positioning System (GPS) multipath signals

Yang, Zhenghong January 1998 (has links)
No description available.
98

Algorithms and Architectures for UWB Receiver Design

Ibrahim, Jihad E. 26 March 2007 (has links)
Impulse-based Ultra Wideband (UWB) radio technology has recently gained significant research attention for various indoor ranging, sensing and communications applications due to the large amount of allocated bandwidth and desirable properties of UWB signals (e.g., improved timing resolution or multipath fading mitigation). However, most of the applications have focused on indoor environments where the UWB channel is characterized by tens to hundreds of resolvable multipath components. Such environments introduce tremendous complexity challenges to traditional radio designs in terms of signal detection and synchronization. Additionally, the extremely wide bandwidth and shared nature of the medium means that UWB receivers must contend with a variety of interference sources. Traditional interference mitigation techniques are not amenable to UWB due to the complexity of straight-forward translations to UWB bandwidths. Thus, signal detection, synchronization and interference mitigation are open research issues that must be met in order to exploit the potential benefits of UWB systems. This thesis seeks to address each of these three challenges by first examining and accurately characterizing common approaches borrowed from spread spectrum and then proposing new methods which provide an improved trade-off between complexity and performance. / Ph. D.
99

Multipath "Fresnel Zone" Routing for Wireless Ad Hoc Networks

Liang, Yibin 26 March 2004 (has links)
Prior research in routing for wireless ad hoc networks has shown that multipath routing can enhance data delivery reliability and provide load balancing. Nevertheless, only a few multipath routing algorithms have been proposed and their interaction with transport layer protocols has not been thoroughly addressed in the literature. In this work, we propose the multipath “Fresnel zone” routing (FZR) algorithm for wireless ad hoc networks. FZR constructs multiple parallel paths from source to destination based on the concept of “Fresnel zones” in a wireless network. The zone construction method assigns intermediate routers into different “Fresnel zones” according to their capacity and efficiency in forwarding traffic. The central idea in FZR is to disperse traffic to different zones according to network load and congestion conditions, thus achieving better throughput and avoiding congestion at intermediate routers. FZR differs from most existing multipath routing approaches in that both source and intermediate nodes use multiple forwarding paths. FZR also adopts a combination of proactive and on-demand (reactive) approaches to reduce control overhead and latency for packet delivery. Simulation experiments have shown that FZR outperforms unipath distance vector routing, multipath distance vector (MDV) routing, and split multipath routing (SMR) algorithms in quasistatic wireless ad hoc networks. In our simulations, FZR achieves up to 100 percent higher average throughput using the User Datagram Protocol (UDP) and 50 percent higher average throughput using the Transmission Control Protocol (TCP). FZR can also provide better load balancing among different paths, improve network resource utilization, and enable fairer resource allocation among different data transmission sessions. Future work is needed to evaluate FZR in mobile scenarios. / Master of Science
100

New Results on Selection Diversity over Fading Channels

Zhao, Qiang 05 March 2003 (has links)
This thesis develops a mathematical framework for analyzing the average bit error rate performance of five different selection diversity combining schemes over slow, frequency non-selective Rayleigh, Nakagami-m and Ricean fading channels. Aside from the classical selection diversity, generalized selection combining and the "maximum output" selection methods, two new selection rules based on choosing the branch providing the largest magnitude of log-likelihood ratio for binary phase shift keying signals (with and without phase compensation in the selection process) are also investigated. The proposed analytical framework is sufficiently general to study the effects of dissimilar fading parameter and unequal mean received signal strengths across the independent diversity paths. The effect of branch correlation on the performance of a dual-diversity system is also studied. The accuracies of our analytical expressions have been validated by extensive Monte-Carlo simulation runs. The proposed selection schemes based on the log-likelihood ratio are attractive in the design of low-complexity rake receivers for wideband CDMA and ultra wideband communication systems. / Master of Science

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