Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 247-259). Also available on the Internet.

Thesis (M.S.)--Tennessee Technological University, 2009. / Title from title page screen (viewed on Feb. 9, 2010). Bibliography: leaves 102-108.

Unlike traditional cellular networks, where voice calls dominate the network traffic, modern mobile traffic is created by of a mixture of both voice and broadband data services. The heterogeneous mixture of voice and data services in mobile broadband networks includes voice calls, web browsing, file transfers, video streaming, and social media applications. Consequently, network planning and radio resource management strategies must be aware of the quality of experience perceived by the users using various types of applications. In this report, we explore the traffic characteristics, scheduling and resource allocation strategies, and user experience models in mobile broadband networks. / text

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ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / In this paper, we propose a novel technique using a single antenna for direction of arrival (DOA) estimation of broadband microwave signals. We designed and fabricated a microstrip-leaky-wave receiving antenna, which has good matching and reasonable radiation efficiency in the frequency range of interest: 2 - 3.5 GHz. Because the frequency response of the antenna is strongly incident-angle dependent, by using the spectral information at the antenna, we are able to estimate the DOA of a broadband microwave signal with a high degree of accuracy. Simulations and experiments show that the proposed technique enables good DOA estimation performance within a 90˚ range.

published_or_final_version / abstract / toc / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

The modern computing industry tends to build integrated circuits with multiple energy-efficient cores instead of ramping up the clock speed for each single processing unit. While each core may not run as fast as the single core model, such architecture allows more jobs to be handled in parallel and also provides better overall performance. Asymmetric Multiprocessing, also known as Heterogeneous Multiprocessing, involves multiple processors that differ architecturally from one another, especially where each processor has its own memory space. Under power limitations, this design could provide better performance than that attained through symmetric multiprocessing. However, the heterogeneous nature adds difficulty to programming. Each specific architecture requires its own program code. Programmers also need to explicitly transfer code and data between processors. This study describes the implementation of a compiler of the pedagogic Tiger language for the Cell Broadband Engine, an asymmetric multiprocessing platform jointly developed by Sony, Toshiba and IBM. The problem above is solved by introducing multiple backends for the Tiger language, along with a remote call stub (RCS) generator. Functions are compiled into different architectures, and calls across architectures are linked automatically through the stubs. RCS takes care of the execution context switch and hides details of the argument data/return value transfer. TigC simplifies the programming and building procedures. It also provides a high-level view of the whole program execution for future optimization because all of the source files are processed by a single compiler. As an example of this procedure, the possible optimization of data transfer during remote calls is investigated here.

Broadband Wireless Access Systems (BWASs) such as High Speed Downlink Packet Access (HSDPA) and the Worldwide Interoperability for Microwave Access (WiMAX), pose a myriad of new opportunities for leveraging the support of a wide range of “content-rich” mobile multimedia services with diverse Quality of Service (QoS) requirements. This is due to the remarkably high bandwidth that is supported by these systems, which was previously only available to wireline connections. Despite the support for such high bandwidth, satisfying the diverse QoS of users while maximizing the revenues of network operators is still one of the major issues in these systems. Bandwidth management, therefore, will play a decisive role in the success of such wireless access systems. Without efficient bandwidth management, network operators may not be able to meet the growing demand of users for multimedia services, and may consequently suffer great revenue loss. Bandwidth management in BWASs is, however, a challenging problem due to many issues that need to be taken into consideration. Examples of such issues include the diverse QoS requirements of the services that BWASs support, the varying channel quality conditions of mobile users, and hence the varying amount of resources that are needed to guarantee certain QoS levels during the lifetime of user connections, the utilization of shared channels for data delivery instead of dedicated ones and network congestion. In this thesis, we address the problem of bandwidth management in BWASs and propose efficient economic-based solutions in order to deal with these issues at different bandwidth management levels, and hence enhance the QoS support in these systems. Specifically, we propose a bandwidth management framework for BWASs. The framework is designed to support multiple classes of traffic with different users having different QoS requirements, maximize the throughput of BWASs, support inter- and intra-class fairness, prevent network congestion and maximize the network operator’s revenues. The framework consists of three related components, namely packet scheduling, bandwidth provisioning and Call Admission Control-based dynamic pricing. By efficiently managing the wireless bandwidth prior to users’ admission (i.e.,pre-admission bandwidth management) and during the users’ connections (i.e., post-admission bandwidth management), these schemes are shown to achieve the design goals of our framework. / Thesis (Ph.D, Computing) -- Queen's University, 2009-04-01 15:35:36.213

With the increasing market demand for wideband multifunctional electronic systems, real-time broadband measurement systems with few picoseconds switching rates are essential. Furthermore, stable millimeter wave sources are required to drive these wideband electronic systems. Nonlinear transmission lines (NLTLs) are high impedance transmission lines periodically loaded with reverse biased diode serving as varactors. Extremely high bandwidths are achievable because of the possibility to fabricate these structures monolithically, which is why pulses with ultra short transitions can be generated using NLTLs. Also, efficient wideband frequency conversion is made possible by NLTL technology. / In this thesis, a comprehensive study of NLTLs and their applications is presented. Sharpening of the edges of electrical pulses, voltage dependent true time delay, and harmonic generation in NLTLs are investigated through analytical studies as well as circuit simulations and experimental measurements. Designing the best possible mixers, frequency doublers, and edge sharpeners and optimizing them are not the objects of this thesis. The main objective is to study an alternative design approach by using NLTLs. To this end, analytical solution for the magnitude of the third harmonic along a nonlinear transmission line is derived for the first time. Also, for the first time the lowpass nature of the NLTL is combined with the solutions for the magnitudes of harmonics in order to improve the validity range of the predicted harmonics. An NLTL harmonic generator is fabricated and measurement results are reported. / Inspired by the distributed nature of nonlinear transmission lines, a novel filtering method is introduced for the suppression of the unwanted signals in different NLTL applications. The filtering method is applied to a nonlinear transmission line frequency multiplier in order to filter the third harmonic. The distributed filtering is also used to suppress the image signal in an NLTL mixer. The proposed filtering method is general and can be applied to other periodic structure as well (such as distributed amplifiers and distributed mixers). For implementing the filtering, compact complementary split ring resonators are proposed and designed for an NLTL frequency doubler.

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