Dissertations / Theses: 'Global Systems for Mobile Communications'

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Chan, Ka Chun. "A dual channel location estimation system for mobile computing." HKBU Institutional Repository, 2003. http://repository.hkbu.edu.hk/etd_ra/445.

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Liu, Tuo. "Analytical modeling of HSUPA-enabled UMTS networks for capacity planning." Connect to full text, 2008. http://ses.library.usyd.edu.au/handle/2123/4055.

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Thesis (Ph. D.)--University of Sydney, 2009.
Title from title screen (viewed February 20, 2009). Includes graphs and tables. Includes list of publications co-authored with others. Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Information Technologies, Faculty of Engineering and Information Technologies. Degree awarded 2009; thesis submitted 2008. Includes bibliographical references. Also available in print form.

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Prince, Castro Jonathan Castro Jonathan Prince. "A global satellite system for mobile communications /." [S.l.] : [s.n.], 1995. http://library.epfl.ch/theses/?nr=1300.

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Lee, See Taur. "Quad-band global system for mobile communications complementary metal-oxide-semiconductor transmitter /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/6122.

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Kan, Ka Ho. "Location estimation system based on the GSM network." HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/524.

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Darweesh, Turki H. "Capacity and performance analysis of a multi-user, mixed traffic GSM network." Ottawa, 1999.

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Maharaj, Robin. "Design of asset tracking device with GPRS Interface." Thesis, Cape Peninsula University of Technology, 2019. http://hdl.handle.net/20.500.11838/2815.

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Thesis (Master of Engineering in Electrical Engineering)--Cape Peninsula University of Technology, 2018.
IOT devices have the potential to improve asset lifecycle optimization because of their ability to provide relevant real time data to high level applications. This data with minimal latency can assist asset managers to control the behaviour of assets and asset users to optimize asset lifecycle cost. There are many environments that require asset tracking devices but this design focussed on motor vehicles with auxiliary functions and apparatus. This research work documented the design of an asset tracking device built and tested on a 32.bit microcontroller platform with built-in CAN peripheral. This design resolved handling multiple serial interfaces collating data simultaneously concatenating this data and transmitting the data via GPRS interface as a single UDP sentence. Apart from interfacing various serial interfaces to the Stm24f4 this design also implemented a Wireless module as well as a multichannel ADC Module. This design was accomplished by researching and implementing software techniques as well as researching the hardware/firmware in terms of DMA and Nested Vector Interrupt Controller of the STM32 devices. The solution that this design will accomplish is to provide the industry an asset-tracking device with data capturing functionality capable of delivering the above needs at reasonable data cost. The device designed in this thesis is the client device of asset tracking network. This design was accomplished on a proof of concept basis delivering built hardware in the form of various application modules interfaced to a 32 –bit microcontroller via uart, SPI and CAN.

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Chu, Man Kin. "A hybrid approach for mobile location estimation in cellular radio networks." HKBU Institutional Repository, 2006. http://repository.hkbu.edu.hk/etd_ra/672.

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Wang, Wenye. "Location management techniques for next generation wireless systems." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/13289.

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Hill, Ryan Tebbutt. "Adaptive interfaces for mobile preference-based searching." Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/1248.

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Today's mobile computing devices provide a convenient means to search for points-of-interest (POIs) such as restaurants and accommodation. Mobile Preference-Based Search Tools (PBSTs) allow users to identify POIs such as restaurants or accommodation most suited to their needs and constraints using a mobile device. These devices however, have several design constraints including limited screen space and hardware capabilities. Adaptive User Interfaces (AUIs) have been proposed to address these issues but have not been extensively applied to mobile PBSTs such as mobile tourist guides. In addition, AUIs possess several benefits and advantages over static (traditional) interfaces, which do not take a user's preferences, skill set and experience into account. Little research, however, has been conducted into identifying the potential benefits of AUIs for mobile preference-based searching (PBS). The aim of this research was to determine the extent to which an AUI could improve the effectiveness and user satisfaction of mobile PBS. A literature study was conducted to determine the benefits and limitations of existing mobile PBSTs and determine how these could be improved. The potential benefits of AUIs for mobile PBSTs and a mobile map-based visualisation system were identified. A suitable model for incorporating an AUI into a mobile PBST was identified. The requirements for a mobile PBST were combined with the potentially adaptable objects of a Mobile Map-based Visualisation (MMV) system to provide adaptation suggestions for POInter, an existing mobile tourist guide. A field study using POInter was conducted in order to measure the extent to which participants agreed with suggestions provided for adapting the information, interaction and visualisation aspects of the system. These results were used to derive adaptation requirements for A-POInter, an adaptive version of POInter. Using a model-based design approach, an AUI was designed and implemented for A-POInter. An extensive field study was then conducted to evaluate the usability of the adaptations provided by A-POInter. The quantitative and qualitative data collected from the evaluations allowed the usability of A-POInter to be determined. The results of the field study showed that the participants were highly satisfied with the usability and the usefulness of the adaptations provided by A-POInter. Conclusions and recommendations for future work based on the results of the research were then outlined to conclude the dissertation.

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Cuvelliez, Charles. "Etudes des modèles d'implémentation des opérateurs de réseaux mobiles virtuels." Doctoral thesis, Universite Libre de Bruxelles, 2006. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210895.

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This thesis addresses the phenomena of Mobile Virtual Network Operators (MVNO): often MVNO do not come from the telecom sector but they rent the network to mobile operators to become fully mobile operators on their own. So they compete directly not only with the other mobile operators but also with their hosting mobile operator.

Hosting MVNOs, supporting them from both operational and commercial perspectives are new challenges for the mobile operators: they have to set up a specific internal organization because they used to be a vertically integrated industrial structure. All of this represents tremendous changes for them.

This thesis describes first the strategic models for hosting MVNOs. The regulatory aspects, that are an essential driver for the liberalization of network economies, are then analyzed. The key point is: are the MVNO able to increase the efficiency and competitiveness of mobile markets.

Another important aspect is the modelling of a mobile network: the MVNOs will use some components while other components are unuseful for them. Without such model, it is impossible to derive the right costs and price to be charged to the MVNO in order to have a win win industrial model for both the MVNO and its hosting operator.

A case study of a corporate MVNO focusing on needs of multinationals is analyzed. Such case study describes all the steps for an economic actor to become MVNO from scratch. Such MVNO are not yet present although there is a market demand.

The last chapter makes a comparative study of the MVNO markets in the European Union.

Cette étude aborde le phénomène des opérateurs de réseaux mobiles virtuels ;il s’agit d’acteurs économiques - parfois sans lien aucun avec les télécommunications - qui louent le réseau d’opérateurs mobiles ;ils deviennent à leur tour opérateurs à part entière au point de devenir concurrent non seulement des autres opérateurs mobiles mais aussi de l’opérateur mobile qui leur a loué une partie de son réseau.

L’hébergement technique de l’opérateur virtuel, son support opérationnel et commercial, l’organisation que doit mettre en place l’opérateur mobile pour héberger son opérateur virtuel afin de partager avec lui son réseau sont des nouveaux défis auxquels les opérateurs mobiles, habitués à être des structures industrielles totalement intégrées verticalement, font face pour la première fois.

Cette étude traite des modèles d’implémentation des opérateurs de réseaux mobiles virtuels :elle aborde d’abord les aspects stratégiques qui fixent le cadre pour les opérateurs mobiles qui veulent ou sont forcés à héberger des opérateurs virtuels. Les aspects réglementaires, une composante essentielle des économies de réseaux en voie de libéralisation, sont ensuite étudiés, en particulier, comment les opérateurs virtuels peuvent contribuer à améliorer la compétitivité et la libéralisation de ces marchés.

L’étude modélise ensuite le réseau d’un opérateur mobile de façon à mettre en évidence les éléments à partager qui seront utilisés par l’opérateur virtuel. Cette modélisation est essentielle pour déterminer le coût de l’hébergement et du partage du réseau de façon à créer les conditions de rentabilité de ce modèle d’opérateur virtuel.

On aborde enfin un cas d’étude d’un candidat à devenir opérateur de réseau mobile virtuel qui souhaite répondre à la demande transnationale des grandes entreprises. Ce type d’opérateur virtuel est encore inexistant de nos jours.

Enfin, nous terminons par une étude comparée de la situation des opérateurs mobiles virtuels à travers l’Union Européenne.

Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished

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Pozzobon, Oscar. "Secure location services : vulnerability analysis and provision of security in location systems /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18315.pdf.

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Axelsson, Karin, and Cynthia Novak. "Support for Cell Broadcast as Global Emergency Alert System." Thesis, Linköping University, Department of Science and Technology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-9491.

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Cell Broadcast (CB) is a possible technical realisation of a global emergency alert system. It is a technique used for sending short text messages to all mobile stations (MSs) in a defined geographical area. An potential effect of using CB is the increase in battery consumption of the MS due to the fact that an extra channel has to be used to make the service available even when the network is otherwise congested. Another part of the service which leads to a potential problem is making CB messages available in different languages. Investigating these problems is the objective of this thesis and the studies it includes. During the first part of the thesis, we measured the battery consumption of MSs in different modes of operation in order to analyse how CB affects the amount of current drained. The tests showed that battery consumption increased only slightly when CB messages were being received at the MS. Although some of the results can be, and are, discussed, we believe that CB would have a small effect on the power consumption of an MS, particularly in a context where it would be used for emergency warning messages only. This mentioned, it would however be wishful to confirm the conclusions further through the realisation of long-term testing. The second part of the thesis deals with the investigation of the MSs’ support for CB messages with different coding schemes. Based on the investigation’s result, we have come to the conclusion that in the long term the usage of different coding schemes on the same channel is preferred. However, the usage of one, global, emergency channel is hard to realise since that requires a standardisation between all countries. In our opinion this may be achieved first in the long run and until then, the usage of separate channels seems to be necessary.

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Sharma, Bishal. "Radio frequency optimization of a Global System for Mobile (GSM) network." Menomonie, WI : University of Wisconsin--Stout, 2008. http://www.uwstout.edu/lib/thesis/2008/2008sharmab.pdf.

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Shum, Chin Yiu. "Detecting, locating, and tracking mobile user within a wireless local area network." HKBU Institutional Repository, 2013. http://repository.hkbu.edu.hk/etd_ra/1512.

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McAbee, Carson C. "Software-defined radio global system for mobile communications transmitter development for heterogeneous network vulnerability testing." Thesis, Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/38978.

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Approved for public release; distribution is unlimited.
The conversion from homogeneous global system for mobile communications (GSM) networks to heterogeneous GSM/universal mobile telecommunications system (UMTS) networks is rapidly expanding. Previous research identified vulnerabilities in the GSM network that were fixed in the UMTS standard; however, the mobile device must successfully access the UMTS network to take advantage of security improvements. Therefore, a possible vulnerability not addressed in either the GSM or UMTS standards is the potential for a malicious entity to prevent a mobile device from handing over from a GSM to UMTS network, because the GSM network maintains the stand-alone dedicated control channel (SDCCH) uplink time slots. The process of testing this vulnerability requires the development of a device that monitors a GSM base transceiver station, identifies when a handover to UMTS message is sent, tracks the time slots of the SDCCH uplink, and transmits a GSM handover-failure message. In this thesis, we present an open-source coding scheme that utilizes parts of the OpenBTS source code to transmit a GSM handover-failure message using the universal software radio peripheral. The method is validated through the collection of the GSM transmitter messages by Airprobes GSM-receiver software.

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Nellaiappan, Kalaivani. "Gobuddy - Android mobile application." CSUSB ScholarWorks, 2011. https://scholarworks.lib.csusb.edu/etd-project/3323.

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The purpose of this application is to serve the end user of an Android Smart phone, with reliable, instantaneous and location based information on places of interest such as restaurants, gas stations, hotels, movie theaters, and the like by using the phones' built-in GPS. The basic information includes viewing the map and address of the place of interest and getting the directions to a particular place in addition to having some extra features. Contains computer source code.

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Falk, Lolita. "Konstruktion av SMS-Gateway för effektökande SMS-tjänster." Thesis, University West, Department of Informatics and Mathematics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-594.

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Sakpere, Wilson Evuarherhe. "A near field communication framework for indoor navigation : design and deployment considerations." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/2290.

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Thesis (MTech (Information Technology))--Cape Peninsula University of Technology, 2015.
Navigation systems are known to provide time and location information for easy and accurate navigation in a specified environment. While Global Positioning System (GPS) has recorded a considerable success for navigating outdoors, the absence of GPS indoors has made orientation in an indoor environment challenging. Furthermore, existing technologies and methods of indoor positioning and navigation, such as WLAN, Bluetooth and Infrared, have been complex, inaccurate, expensive and challenging to implement; thereby limiting the usability of these technologies in less developed countries. This limitation of navigation services makes it difficult and time consuming to locate a destination in indoor and closed spaces. Hence, recent works with Near Field Communication (NFC) has kindled interest in positioning and navigation. While navigating, users in less developed nations face several challenges, such as infrastructure complexity, high-cost solution, inaccuracy and usability. However, this research focuses on providing interventions to alleviate usability challenges, in order to strengthen the overall accuracy and the navigation effectiveness in stringent environments through the experiential manipulation of technical attributes of the positioning and navigation system in indoor environments. Therefore, this study adopted the realist ontology and the positivist epistemological approach. It followed a quantitative and experimental method of empirical enquiry, and software engineering and synthesis research methods. The study entails three implementation processes, namely map generation, positioning framework and navigation service using a prototype mobile navigation application that uses the NFC technology. It used open-source software and hardware engineering tools, instruments and technologies, such as Ubuntu Linux, Android Software Development Kit, Arduino, NFC APIs and PandaBoard. The data was collected and the findings evaluated in three stages: pre-test, experiment and post-test.

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Van, der Walt Tjaart. "The management and implementation of a data terminal project on a global system for mobile communications / Tjaart van der Walt." Thesis, Potchefstroom University for Christian Higher Education, 1999. http://hdl.handle.net/10394/9613.

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With the demand for more control over remote systems and access to remote data increasing, there existed the need for a more efficient and low cost means of transmitting this data. Traditionally, small telemetry data packets have been transmitted using unreliable direct radio frequency links, or expensive copper connections or satellite communications. With the international infrastructure of the Global System for Mobile communication (GSM) networks and it's ever-improving coverage, GSM has become a viable solution as the data channel for data telemetry. With a data terminal, remote monitoring of processes in a factory plant with real-time access to the parameters will be possible. If the per-unit cost is low enough, there would be a use for it in pre-paid energy metering, or even in the control of peak energy demand. The goal of this project was twofold: firstly to apply a structured project management approach to the design cycle of a data terminal, and secondly to design such a terminal in the shortest possible time. It was anticipated that the use of a structured management process would reduce the development time. The data terminal was not designed for a specific customer, but was to be as versatile and flexible as possible. It is understood that only a percentage of all telemetry applications will be able to use such a device, and the trade-off was to balance the cost of the unit (and functionality) with too much complexity. The project was completed in a relatively short time, and the terminal found to be extremely flexible. The unit cost was kept low as compared to other systems. In fact, the complete unit will cost the end user less than just the communication devices in the trunk radio and satellite systems it can replace. The short message service (SMS) as a communication channel has proven itself to be more reliable and of lower cost than other competing technologies. The ongoing expansion and improvement of the GSM networks by their operators, also ensure a stable platform for future use of the data terminal.
Thesis (MIng (Electrical Engineering))--PU for CHE, 1999

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Hensley, Phillip Hayden. "Development and Analysis of a Mobile Node Tracking Antenna Control System." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1011810/.

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A wireless communication system allows two parties to exchange information over long distances. The antenna is the component of a wireless communication system that allows information to be converted into electromagnetic radiation that propagates through the air. A system using an antenna with a highly directional beam pattern allows for high power transmission and reception of data. For a directional antenna to serve its purpose, it must be accurately pointed at the object it is communicating with. To communicate with a mobile node, knowledge of the mobile node's position must be gained so the directional antenna can be regularly pointed toward the moving target. The Global Positioning System (GPS) provides an accurate source of three-dimensional position information for the mobile node. This thesis develops an antenna control station that uses GPS information to track a mobile node and point a directional antenna toward the mobile node. Analysis of the subsystems used and integrated system test results are provided to assess the viability of the antenna control station.

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Madebwe, Charles. "An investigation into the role played by perceived security concerns in the adoption of mobile money services : a Zimbabwean case study." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1017933.

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The ubiquitous nature of mobile phones and their popularity has led to opportunistic value added services (VAS), such as mobile money, riding on this phenomenon to be implemented. Several studies have been done to find factors that influence the adoption of mobile money and other information systems. The thesis looks at factors determining the uptake of mobile money over cellular networks with a special emphasis on aspects relating to perceived security even though other factors namely perceived usefulness, perceived ease of use, perceived trust and perceived cost were also looked at. The research further looks at the security threats introduced to mobile money by virtue of the nature, architecture, standards and protocols of Global System for Mobile Communications (GSM). The model employed for this research was the Technology Acceptance Model (TAM). Literature review was done on the security of GSM. Data was collected from a sample population around Harare, Zimbabwe using physical questionnaires. Statistical tests were performed on the collected data to find the significance of each construct to mobile money adoption. The research has found positive correlation between perceived security concerns and the adoption of money mobile money services over cellular networks. Perceived usefulness was found to be the most important factor in the adoption of mobile money. The research also found that customers need to trust the network service provider and the systems in use for them to adopt mobile money. Other factors driving consumer adoption were found to be perceived ease of use and perceived cost. The findings show that players who intend to introduce mobile money should strive to offer secure and useful systems that are trustworthy without making the service expensive or difficult to use. Literature review done showed that there is a possibility of compromising mobile money transactions done over GSM

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Cheng, Quan Jia. "A WLAN location estimation system using center of gravity as an algorithm selector." HKBU Institutional Repository, 2013. http://repository.hkbu.edu.hk/etd_ra/1513.

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Cloppenburg, Jürgen. "The regulation of global mobile personal communications by satellite : a comparative analysis of regulations, policy and perspectives in the European Union, in particular Germany, and the United States." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31153.

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This thesis analyses the current regulatory regimes in the European Union---in particular Germany---and the United States governing the authorization of global mobile personal communications by satellite (GMPCS).
Current satellite licensing regimes fail to take into account the international character of satellite telecommunications. The reliance on a national public interest standard does not properly address the interests of the community of states, industry and consumers and is not suitable to meet the aspirations of international space law. The international harmonization of frequencies and international standardization are indispensable for the introduction of these new services. The establishment of an international communications regulator with the power to adopt binding decisions if required is the most suitable way to address these problems. However, the development of an international public interest standard with clear policy objectives will be hard to achieve.
With regard to the different aspects of ground segment licensing, a gradual approach is the best way to balance the different interests and concerns in this field. The International Telecommunications Union GMPCS MoU and the development of European regulations show a feasible way to achieve a regulatory regime that facilitates the introduction of these new services. Lighter regulations, possibly the introduction of one stop shopping procedures, mutual recognition of licenses and the introduction of general authorizations are measures that can and should be taken at the international level. The interdependence of earth and space segment licensing may lead to the understanding that some aspects of earth segment licensing should also be regulated at international level.
The question will be whether States, industry and users are able to reconcile their interests and the sometimes opposing trends of international cooperation and international competition for the benefit of "all mankind".

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Jenkins, William George. "Real-time vehicle performance monitoring with data integrity." Master's thesis, Mississippi State : Mississippi State University, 2006. http://sun.library.msstate.edu/ETD-db/ETD-browse/browse.

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Light, Brandon W. "Energy-efficient photon mapping." Link to electronic thesis, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-051007-092224/.

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Thesis (M.S.) -- Worcester Polytechnic Institute.
Keywords: mobile devices; photon mapping; global illumination; ray tracing; energy; mobile; computer graphics. Includes bibliographical references (leaves 66-68).

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Chan, Francis Chun Ngai Electrical Engineering &amp Telecommunications Faculty of Engineering UNSW. "Statistical methods on detecting superpositional signals in a wireless channel." Awarded by:University of New South Wales. School of Electrical Engineering and Telecommunications, 2006. http://handle.unsw.edu.au/1959.4/30596.

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The objective of the thesis is concerned on the problem of detecting superpositional signals in a wireless channel. In many wireless systems, an observed signal is commonly represented as a linear combination of the transmitted signal with the interfering signals dispersed in space and time. These systems are generally known as the interference-limited systems. The mathematical model of these systems is generally referred as a superpositional model. A distinguished characteristic of signal transmission in a time-varying wireless channel is that the channel process is not known a priori. Reliable signal reception inherently requires exploiting the structure of the interfering signals under channel uncertainty. Our goal is to design computational efficient receivers for various interference-limited systems by using advanced statistical signal processing techniques. The thesis consists of four main parts. Firstly, we have proposed a novel Multi-Input Multi-Output (MIMO) signal detector, known as the neighbourhood exploring detector (NED). According to the maximum likelihood principle, the space time MIMO detection problem is equivalent to a NP-hard combinatorial optimization problem. The proposed detector is a sub-optimal maximum likelihood detector which eliminates exhaustive multidimensional searches. Secondly, we address the problem of signal synchronization for Global Positioning System (GPS) in a multipath environment. The problem of multipath mitigation constitutes a joint estimation of the unknown amplitudes, phases and time delays of the linearly combined signals. The complexity of the nonlinear joint estimation problem increases exponentially with the number of signals. We have proposed two robust GPS code acquisition systems with low complexities. Thirdly, we deal with the problem of multipath mitigation in the spatial domain. A GPS receiver integrated with the Inertial Navigation System (INS) and a multiple antenna array is considered. We have designed a software based GPS receiver which effectively estimates the directions of arrival and the time of arrival of the linearly combined signals. Finally, the problem of communications with unknown channel state information is investigated. Conventionally, the information theoretical communication problem and the channel estimation problem are decoupled. However the training sequence, which facilitates the estimation of the channel, reduces the throughput of the channel. We have analytically derived the optimal length of the training sequence which maximizes the mutual information in a block fading channel.

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Ferreira, Fábio Miguel Lopes. "Controlo de sistemas M2M com fotografias georreferenciadas." Master's thesis, Universidade de Aveiro, 2010. http://hdl.handle.net/10773/7644.

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Mestrado em Engenharia Electrónica e Telecomunicações
Com esta dissertação pretende-se estudar e projectar um sistema de controlo e comunicação Machine to Machine que monitorize elementos móveis, por recurso a comunicações via GSM/UMTS (Global System for Mobile Communications/Universal Mobile Telecommunications System). A ideia do projecto é monitorizar e recolher informação telemática de um veículo utilizando a rede GSM/UMTS. As informações colectadas são, as coordenadas GPS, e informações referentes à antena GSM à qual o dispositivo se encontra ligado, assim como a recolha de fotografias. O dispositivo criado permite assim a georreferenciação fotográfica, sendo um excelente método para segurança e monitorização remota.
This dissertation's concern is the study and design of a system for control and communication Machine to Machine for mobile elements monitorization, communicating by GSM / UMTS (Global System for Mobile Communications / Universal Mobile Telecommunications System). The project goal is to collect and monitorize a vehicle's telematic information using the GSM / UMTS. The collected information consists of the GPS coordinates and information about the GSM antenna to which the device is connected, as well as a collection of photographs. Hence, the created device allows for photographic geo-reference, which is a reliable solution for both security and remote monitorization.

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Nehme, Rimma V. "Continuous query processing on spatio-temporal data streams." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-082305-154035/.

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Aniruddhan, Sankaran. "A fast-locking frequency synthesizer for GSM base-stations in 180nm CMOS /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/5952.

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Li, Yafei. "Efficient group queries in location-based social networks." HKBU Institutional Repository, 2015. https://repository.hkbu.edu.hk/etd_oa/203.

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Nowadays, with the rapid development of GPS-equipped mobile devices, location-based social networks have been emerging to bridge the gap between the physical world and online social networking services. Various types of data, such as personal locations, check-ins, microblogs and social relations, have been available in location-based social networks. Efficiently managing and analyzing such data to meet users' daily query requirements become a challenging task. Among all the existing works in location-based social networks, group query is one of the most important research topics. In this thesis, we investigate query techniques for location-based services in social networking applications. Specifically, considering a location-based social network, we study spatial-aware interest group queries, geo-social {dollar}k{dollar}-cover group queries, and social-aware ridesharing group queries. Firstly, we study the spatial-aware interest group queries in location-based social networks. Recently, most of the location-based social networks release check-in services that allow users to share their visiting locations with their friends. These locations, considered as spatial objects, are usually associated with a few tags that describe the features of those locations. Utilizing such information, we propose a new type of \emph{Spatial-aware Interest Group} (SIG) query that retrieves a user group of size {dollar}k{dollar} where each user is interested in the query keywords and the users are close to each other in the Euclidean space. We prove this query problem is NP-complete, and develop two efficient algorithms IOAIR and DOAIR based on the IR-tree for the processing of SIG queries. We also validate the performance efficiency of the proposed query processing algorithms by empirical evaluation. Secondly, we study the problem of geo-social {dollar}k{dollar}-cover group queries for collaborative spatial computing. In this problem, we propose a novel type of geo-social queries, called \emph{Geo-Social K-Cover Group} (GSKCG) query, which is based on spatial containment and a new modeling of social relationships. Intuitively, given a set of spatial query points and an underlying social network, a GSKCG query finds a minimum user group in which the members satisfy certain social relationship and their associated regions can jointly cover all the query points. Albeit its practical usefulness, the GSKCG query problem is NP-complete. We consequently explore a set of effective pruning strategies to derive an efficient algorithm for finding the optimal solution. Moreover, we design a novel index structure tailored to our problem to further accelerate query processing. Extensive experiments demonstrate that our algorithm achieves desirable performance on real-life datasets. Thirdly, we study the problem of social-aware ridesharing group queries. With the deep penetration of smartphones and geo-locating devices, ridesharing is envisioned as a promising solution to transportation-related problems such as congestion and air pollution for metropolitan cities. Despite the potential to provide significant societal and environmental benefits, ridesharing has not so far been as popular as expected. Notable barriers include the social discomfort and safety concerns when traveling with strangers. To overcome these barriers, in this thesis, we propose a new type of \emph{Social-aware Ridesharing Group} (SaRG) query which retrieves a group of riders by taking into account their social connections besides traditional spatial proximities. Because the SaRG query problem is NP-hard, we design an efficient algorithm with a set of powerful pruning techniques to tackle this problem. We also present several incremental strategies to accelerate the search speed by reducing the repeated computations. Moreover, we propose a novel index tailored to the proposed problem to further speed up the query processing. Experimental results on real datasets show that our proposed algorithms achieve desirable performance. The works of this thesis show that the group query processing techniques are effective, which would facilitate the wider deployment of such query services in real applications

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Iraba, Marie Louise. "Inexpensive mobile technologies to empower rural farmers with m-agriculture." Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_9526_1370595447.

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Market information and established communication between seller and buyer play an important role in business activities. This thesis investigates the Transkei area in the Eastern Cape
Province, South Africa to find out how to empower rural farmers by providing them with less-expensive mobile technology enabling them to post and advertise their produce, access market
information on a common database, and find and communicate with potential customers. The farmers&rsquo
requirements were identified using quantitative and qualitative methods and a prototype
consisting of USSD and web applications was developed. It allows the farmer to follow a sequence of menu commands to send a request to the database and access market information, such
as commodity prices, and post information about their own produce so as to attract more customers. The low cost of USSD and the ubiquity of mobile phones enable the system to be usable, affordable and effective. During the final stage of development, the system was tested successfully and addressed a major problem faced by farmers, i.e. lack of access to market information.

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Silva, Vanessa Sérgio da. "Sistemas de M2M utilizando GSM." Master's thesis, Universidade de Aveiro, 2010. http://hdl.handle.net/10773/5602.

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Mestrado em Engenharia Electrónica e Telecomunicações
Com esta dissertação pretende-se estudar e projectar um sistema de controlo e comunicação M2M (Machine to Machine) que monitorize elementos móveis, por recurso a comunicações GSM (Global System for Mobile Communications). A solução proposta implica monitorizar e colectar informação telemática de um veículo, utilizando o canal GSM. O dispositivo utilizado consiste num módulo GSM/GPS, programado por linguagem Python, de forma a permitir obter informação específica via GPRS. O trabalho desenvolvido foi ainda integrado numa base de dados GIS em desenvolvimento no Instituto de Telecomunicações de Aveiro.
This dissertation aims to study and design a system for control and communication M2M (Machine to Machine) for mobile elements monitorization, using the communications GSM (Global System for Mobile Communications). The proposed solution involves collecting information and monitoring a vehicle‟s telematic data, using the GSM channel. The device used consists of a module GSM/GPS, programmed in Pyhton language, to allow specific information via GPRS. This work was also integrated into a GIS database developed at the Institute of Telecommunications Aveiro.

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Blood, Alan Physics Faculty of Science UNSW. "Biological effects of GSM mobile phone microwave radiation: an investigation of gene expression." Awarded by:University of New South Wales. School of Physics, 2005. http://handle.unsw.edu.au/1959.4/22071.

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There is evidence that athermal radiofrequency radiation can alter Heat Shock Protein (HSP) expression or protein phosphorylation, or alter MAP kinase signalling. Effects of long-term exposure in brain tissue due to repeated HSP perturbation (eg an inhibition of apoptosis) have been hypothesised (French et al, 2001). This study aimed to investigate the RNA expression profile (12,000 genes) and HSP family protein expression levels after either acute 1-hour or chronic 4-day intermittent exposures to simulated GSM radiation in a human primary fibroblast model. The results found minimal or no effects of GSM. Flasks were exposed to 900 MHz (217 Hz modulation) at 0.18 W/kg SAR within a Transverse Electromagnetic Mode chamber (TEM cell). Cultures rested for 2 hours before exposures. Affymetrix U95A microarray analysis of a single pilot set of experiments showed that about 40 genes were reported as upregulated >=2.5 fold in each condition. There was no evidence of altered expression of any MAPK-associated genes. Target genes reported in both conditions (CBFA2T1, ZNF148, ITGA1), and genes altered in one condition (CCS, PLEC1, BIRC5), and marginally altered HSP72 were selected for PCR analysis. No other members of the HSP family were altered. In three replicate experiments assayed by real-time PCR, six genes were either unchanged or showed randomly variable expression. However HSP72 RNA showed possible consistent slight upregulation of 1.37 +/- 0.21 in the chronic condition. Western immunoblots of HSP-60, -70, -72 and -V90 proteins showed no significant changes 5 hours after exposure. In preliminary studies using a serum starvation protocol, ERK-1 phosphorylation was unaltered after 5 or 30 minutes GSM (single experiments). When flasks were transiently cooled, ERK-1 phosphorylation was increased 20 minutes later, indicating a source of artefact in some protocols. An inflammatory challenge experiment with a low-dose of the cytokine IL-1???? found that acute GSM exposure post-challenge inhibited NF????B-mediated GRO???? induction by 1.5 fold (2 experiments). Preconditioning with mild heat induces transient inhibition of both NF????B signalling and apoptosis. Other studies indicate that EMF exposures similarly evoke cytoprotection. It is suggested that GSM evoked cytoprotective signalling in this inflammatory model.

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Viljoen, Johannes Henning. "Modelling and optimal control of the market of a telecommunications operator." Diss., Pretoria : [s.n.], 2004. http://upetd.up.ac.za/thesis/available/etd-09152004-100823.

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Cardoza, Andrew Robert. "Middleware for the SUNSAT field station." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52338.

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Thesis (MEng)--University of Stellenbosch, 2001.
ENGLISH ABSTRACT: SRMA currently used on the SUNSAT field station is an effective MAC layer protocol but lacks several features. Sufficient support for flexible communication, acknowledgement of individual data packets, simultaneous communication of multiple instances from a higher layer over a single underlying layer, and a robust FTP procedure to transfer large amounts of data are some of the features that the SUNSA T field station should cater for. ORBCOMM, GSM and WAP implementations are discussed. Some features from these implementations that are useful in the LEO communication environment are designed into an additional layer of software. This additional layer, called middleware, is proposed and uses SRMA services to deliver store-and-forward services. It supports high volumes of short transactions and session suspend and resume facilities between the SUNSA T satellite and field station. Keywords: SUNSAT, Communication, Field station, WAP, GSM, ORBCOMM
AFRIKAANSE OPSOMMING: Die SRMA pakketkommunikasie-protokol op SUNSA T se prototipe grondterminaal is voldoende om die oordrag van boodskappe oor die kommunikasieverbinding te reguleer. Dit is onvoldoende om fasiliteite soos kommunikasie van 'n aantal instansies in 'n hoër kommunikasie laag oor 'n enkele laer laag en om 'n robuuste data oordrag protokol vir groot hoeveelhede data van 'n grondterminaal te ondersteun. ORBCOMM, GSM en WAP stelsel toepassings word bespreek. Resultate wat spruit uit die drie toepassings word gebruik om kommunikasie in 'n lae wentelbaan kommunikasie omgewing te bevorder. 'n Bykomende sagteware laag, bekend as middle-ware, word aanbeveel om voorafgenoemde funksionaliteit mee te implimenteer. Die middle-ware gebruik die beskikbare dienste van die SRMA pakketkommunikasie-protokol om toegang te verkry na die kommunikasie kanaal. Sodoende kan hoë volumes kort transaksies, en sessie-stop en hervat fasiliteite 'n werklikheid gemaak word. Sleutelwoord: SUNS AT, Kommunikasie, grondterminaal, WAP, GSM, ORBCOMM

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Oliveira, Gabriel Diniz de. "Posicionamento relativo em tempo real e pós-processado utilizando microrreceptor GNSS usado em smartphone." Universidade Federal de Viçosa, 2014. http://locus.ufv.br/handle/123456789/3839.

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Made available in DSpace on 2015-03-26T13:28:35Z (GMT). No. of bitstreams: 1 texto completo.pdf: 8031518 bytes, checksum: 187f1c8078747afc55195475e89c6e44 (MD5) Previous issue date: 2014-07-22
Over time has increased the need for low cost positioning of the populatio, and for this reason the demand for navigation devices has grown considerably in all levels of users of these devices, the population in general has greater access to smartphones because of its many features. Smartphones using micro GNSS receiver has a main component of positioning, where the pseudorange is its basic observable. The data sources for GPS corrections are increasingly available to the community through institutions as the IBGE with the Brazilian Network for Continuous Monitoring (RBMC). Thus, there is a greater possibility of improvement in accuracy of positioning these devices with the post- processed relative positioning and even in real time. With these possibilities and needs, this study aims the establishment of methodology that improves the accuracy in the positioning devices using micro GNSS receiver with a recursive least squares estimation with the Kalman gain matrix applied in relative positioning static by double difference of pseudorange in short baselines. To verify the effectiveness of this methodology is used SiRFstar IV micro receiver data which receives data only in L1 frequency GPS constellation. Was used reference RBMC stations to process these data. With tracking 15 minutes in known points had a mean deviation in the horizontal component of the plane coordinates 29 cm for post-processing and 98 cm for the real time processing, and, for the single point positioning average deviation was 6 meters. With this, it was concluded that the use of static methods for processing on recursive least squares estimation improves the accuracy of positioning significantly, where mobile devices that were previously given only to navigation may also be used for mapping.
Com o passar do tempo aumentou a necessidade da população em posicionamento a baixo custo, e por este motivo a procura por aparelhos de navegação tem crescido consideravelmente em todos os níveis de usuários. Destes dispositivos, a população no geral tem maior acesso aos smartphones devido a suas diversas funcionalidades. Os smartphones utilizam de microrreceptor GNSS como principal componente de posicionamento, sendo que sua observável básica é a pseudodistância derivada do código C/A. As fontes de dados para correções GPS estão cada vez mais disponíveis para a comunidade por meio de instituições como o IBGE com a Rede Brasileira de Monitoramento Continuo dos Sistemas GNSS (RBMC). Com isso, tem-se uma maior possibilidade de melhorias na acurácia do posicionamento destes dispositivos com o posicionamento relativo pós-processado e até mesmo em tempo real. Com estas possibilidades e necessidades, este trabalho tem como objetivo o estabelecimento de metodologia que melhore a acurácia no posicionamento de dispositivos móveis que utilizam microrreceptor GNSS, utilizando a estimativa de mínimos quadrados recursiva com a matriz de ganho de Kalman aplicada no posicionamento relativo estático por dupla diferença da pseudodistância em linhas de base curtas. Para verificar a eficácia desta metodologia utilizou-se dados do microrreceptor SiRFstar IV que recebe dados na frequência L1 da constelação GPS. Foram utilizadas as estações de referência da RBMC para o processamento destes dados. Com rastreios de 15 minutos em pontos de coordenadas conhecidas teve-se um desvio médio na componente horizontal das coordenadas planas de 29 centímetros para o pós- processamento e 98 centímetros para o processamento em tempo real, sendo que, para o posicionamento por ponto simples o desvio médio foi de 6 metros. Com isso, concluiu-se que a utilização da metodologia de processamento relativo estático por estimativa dos mínimos quadrados recursiva melhorou a acurácia do posicionamento de forma significativa, onde dispositivos móveis 14que até então eram indicados somente para navegação podem ser utilizados também para mapeamento.

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38

Van, Graan Sebastiaan Jan. "Network configuration improvement and design aid using artificial intelligence." Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-08292008-170524/.

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Mendes, Luís Miguel Vinhas. "Measurements and analysis of spectrum activity." Master's thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/7725.

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Mestrado em Engenharia Electrónica e Telecomunicações
The dissertation deals with measuring and analyzing spectrum occupancy of a GSM900 band, DCS1800 band and all UMTS bandwidth. A modelization for analog power and binary quantized power is given. In the case of analog power, histograms of the power distribution during one working day are presented. In the case of quantized power the two time statistics, the time period of opportunities distribution and the time between opportunities distribution are presented, described and modeled. The measurement setup is standing in line of sight with the base station. Also, in terms of maximum sensitivity the measurement setup is described and analyzed. Spectrum non occupancy in terms of total time for the GSM900 band and the DCS1800 band is given, for a working day.
Nesta dissertação são feitas medidas e a análise de ocupação de espectro em uma banda de GSM900, uma banda de DCS1800 e toda a largura de banda do UMTS. É apresentada uma modelização para potência analógica e para a potência binária quantizada. No caso da potência analógica são apresentados histogramas da distribuição de potência ao longo de um dia útil. No caso da potência quantizada as duas estatísticas, distribuição do período de tempo de oportunidades e distribuição do tempo entre oportunidades, são apresentadas, descritas e modeladas. O setup de medida encontra-se em linha de vista com a estação base. O setup é descrito e analisado em termos de máxima sensibilidade. A desocupação de espectro em termos de tempo total para a banda de GSM900 e para a banda DCS1800 é fornecida, para um dia de útil.

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Artusi, Denise. "5g mobile communications systems." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7563/.

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Un sistema mobile di comunicazione è un sistema di telecomunicazioni in cui è possibile mantenere la connessione o legame tra due o più utenti, anche nelle situazioni di mobilità totale o parziale degli stessi utenti. I sistemi radiomobili si stanno evolvendo dalla creazione del 1G (prima generazione) al 4G (quarta generazione). I telefoni di ogni generazione si differenziano in quattro aspetti principali : accesso radio, velocità di trasmissione dati, larghezza di banda e sistemi di commutazione. In questa tesi si affronta il tema dei sistemi 5G , negli ambienti terrestri e satellitari , in quanto sono l'ultima evoluzione dei sistemi mobili . Si introduce il passaggio dalla prima alla connessione di quarta generazione , al fine di capire perché 5G sta per cambiare la nostra vita . Quello che mi colpisce è il sito italiano www.Repubblica.it che dice : " con la nuova generazione 5 possiamo affidare le intere porzioni nette di vita". La tecnologia cellulare , infatti , ha cambiato radicalmente la nostra società e il nostro modo di comunicare . In primo luogo è cambiata la telefonia vocale , per poi trasferirsi all' accesso dati , applicazioni e servizi. Tuttavia , Internet non è stato ancora pienamente sfruttato dai sistemi cellulari. Con l'avvento del 5G avremo l'opportunità di scavalcare le capacità attuali di Internet . Il sistema di comunicazione di quinta generazione è visto come la rete wireless reale , in grado di supportare applicazioni web wireless a livello mondiale ( wwww ). Ci sono due punti di vista dei sistemi 5G : evolutivo e rivoluzionario. Dal punto di vista evolutivo, i sistemi 5G saranno in grado di supportare wwww permettendo una rete altamente flessibile come un Adhoc rete wireless dinamica ( DAWN ) . In questa visione tecnologie avanzate, tra cui antenna intelligente e modulazione flessibile , sono le chiavi per ottimizzare le reti wireless ad hoc. Dal punto di vista rivoluzionario, i sistemi 5G dovrebbe essere una tecnologia intelligente in grado di interconnettere tutto il mondo senza limiti . Un esempio di applicazione potrebbe essere un robot wireless con intelligenza artificiale .

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41

Campacci, Rodrigo Bellotto. "Handover vertical em redes NGN: integrando a sinalização do domínio de comutação de circuitos e o IMS." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3141/tde-15092008-152814/.

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Este trabalho visa estudar e implementar a integração entre o domínio de comutação de circuitos e o IP Multimedia Subsystem (IMS) para suportar handovers verticais, ou seja, entre redes de acesso distintas, por exemplo, Global System for Mobile communications (GSM) e WiFi, em especial no Serviço Voice Call Continuity (VCC). Entretanto muito pouco é especificado sobre a integração entre os domínios nas normas das diversas entidades de padronização que tratam sobre o assunto. Assim, apresenta-se uma proposta para essa integração, criando-se uma nova entidade funcional para realizá-la, o Call Data Storage Function (CDSF), que interage com os demais módulos do Serviço VCC e garante que algumas informações que devem ser trocadas entre os módulos não sejam perdidas, devido à conversão de protocolos de sinalização na interface entre tais domínios. O CDSF auxilia também no controle da alocação de endereços de referência utilizados no encaminhamento de chamadas de um domínio para o outro. São definidos os protocolos de acesso ao CDSF, bem como os métodos disponíveis. Em sua concepção, recorre-se a uma modelagem modular, que permite futuras melhorias, apenas por troca de módulos. Como estudos de caso para validar a proposta são apresentados cenários de chamadas que utilizam o Serviço VCC, passando pelo CDSF. Por fim, conclui-se que a integração entre os domínios é viável se a proposta deste trabalho for utilizada. Também se demonstra que a separação dos planos de controle dos planos de dados (de usuário) é uma das contribuições fundamentais da arquitetura NGN para o sucesso de suas implementações, como por exemplo o IMS.Além disso, destacam-se as vantagens que o Serviço VCC pode agregar ao IMS, contribuindo para sua adesão em menor prazo pelas operadoras de telecomunicações, dado que esse serviço contribui para a integração de redes, cada vez mais convergentes, agregando mobilidade e continuidade à sua utilização.
This work intends to study and implement the integration between the circuit switching domain and the IP Multimedia Subsystem (IMS) to support vertical handovers that are between different access networks, such as Global System for Mobile communications (GSM) and WiFi. Therefore the specifications are incomplete about this topic in standards from the entities who works with this subject. Then, is presented a new proposal for this integration: a new functional entity to realize this integration: the Call Data Storage Function (CDSF), which interacts with other modules of VCC Service and guarantees that some information shared between modules are not lost, due to conversion of signalling protocols in the interface between domains. Besides that, CDSF helps in the control of allocation of reference address that are used to route calls from one domain to another. Access protocols to CDSF are defined and CDSF methods are exposed. The CDSF design uses a modular approach, which allows future improvements, just changing modules. As case studies to validate this work proposal, call scenarios are presented that uses the VCC Service, using CDSF. Finally, it is concluded that the integration between domains is viable if this work proposal is used. It is presented, as well, that the separation between control plans and data plans is one of the main contributions of NGN architecture to the success of its implementations, like IMS. Furthermore, it is exposed the advantages that VCC Service can aggregate to IMS, contributing for more rapidly adoption by telecommunications operators, considering that this service helps the networks integration, adding convergence, mobility and continuity.

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42

Arredondo, Alberto. "Downlink beamforming for mobile communications." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3035934.

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43

Patel, Chirag S. "Channel modeling and estimation for mobile-to-mobile OFDM communications." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/13552.

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44

Raad, Raad. "Neuro-fuzzy admission control in mobile communications systems." Access electronically, 2005. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20061030.153500/index.html.

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45

Benson, Maja. "Adaptive space diversity algorithms for mobile communications." Thesis, Staffordshire University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263965.

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46

Hraga, Hmeda I. "Modelling and design of compact wideband and ultra-wideband antennas for wireless communications. Simulation and measurement of planer inverted F antennas (PIFAs) for contemporary mobile terminal applications, and investigations of frequency range and radiation performance of UWB antennas with design optimisation using parametric studies." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/5668.

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The rapidly growing demand for UWB as high data rates wireless communications technology, since the Federal Communications Commission (FCC) allocated the bandwidth of UWB from 3.1GHz to 10.6 GHz. Antenna also plays an essential role in UWB system. However, there are some difficulties in designing UWB antenna as compared to narrowband antenna. The primary requirement of UWB antennas is be able to operate over frequencies released by the FCC. Moreover, the satisfaction of radiation properties and good time domain performance over the entire frequency range are also necessary. In this thesis, designing and analysing printed crescent shape monopole antenna, Planar Inverted F-L Antenna (PIFLA) and Planar Inverted FF Antenna (PIFFA) are focused. A Planar Inverted FF Antenna (PIFFA) can be created to reduce the potential for interference between a UWB system and other communications protocols by using spiral slot. The antennas exhibits broadside directional pattern. The performances such as return loss, radiation pattern and current distribution of the UWB antennas are extensively investigated and carried out. All the results have been demonstrated using simulation and experimentally whereby all results satisfy the performance under - 10dB point in the bandwidth of UWB. In addition the miniaturization of MIMO/diversity Planar Inverted-F antenna (PIFA) which is suitable for pattern diversity in UWB applications is presented. This antenna assembly is formed by two identical PIFAs, a T-shaped decoupling structure which connects the two PIFAs and a finite ground plane with a total compact envelope dimension of 50 ¿ 90 ¿ 7.5mm3. The radiation performance of the proposed MIMO antenna was quite encouraging and provided an acceptable agreement between the computed and measured envelope correlation coefficient and channel capacity loss.
General Secretariat of Education and Scientific Research Libya

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47

Hraga, Hmeda Ibrahim. "Modelling and design of compact wideband and ultra-wideband antennas for wireless communications : simulation and measurement of planer inverted F antennas (PIFAs) for contemporary mobile terminal applications, and investigations of frequency range and radiation performance of UWB antennas with design optimisation using parametric studies." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/5668.

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The rapidly growing demand for UWB as high data rates wireless communications technology, since the Federal Communications Commission (FCC) allocated the bandwidth of UWB from 3.1GHz to 10.6 GHz. Antenna also plays an essential role in UWB system. However, there are some difficulties in designing UWB antenna as compared to narrowband antenna. The primary requirement of UWB antennas is be able to operate over frequencies released by the FCC. Moreover, the satisfaction of radiation properties and good time domain performance over the entire frequency range are also necessary. In this thesis, designing and analysing printed crescent shape monopole antenna, Planar Inverted F-L Antenna (PIFLA) and Planar Inverted FF Antenna (PIFFA) are focused. A Planar Inverted FF Antenna (PIFFA) can be created to reduce the potential for interference between a UWB system and other communications protocols by using spiral slot. The antennas exhibits broadside directional pattern. The performances such as return loss, radiation pattern and current distribution of the UWB antennas are extensively investigated and carried out. All the results have been demonstrated using simulation and experimentally whereby all results satisfy the performance under - 10dB point in the bandwidth of UWB. In addition the miniaturization of MIMO/diversity Planar Inverted-F antenna (PIFA) which is suitable for pattern diversity in UWB applications is presented. This antenna assembly is formed by two identical PIFAs, a T-shaped decoupling structure which connects the two PIFAs and a finite ground plane with a total compact envelope dimension of 50 x 90 x 7.5mm³. The radiation performance of the proposed MIMO antenna was quite encouraging and provided an acceptable agreement between the computed and measured envelope correlation coefficient and channel capacity loss.

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48

Pettersen, Magne. "Three-Dimensional Radio Channel Modeling for Mobile Communications Systems." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Information Technology, Mathematics and Electrical Engineering, 2001. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-89.

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The work described in this report is within the area of three-dimensional (3D) radio channel modeling for mobile communications. The focus was towards rural areas, because radio coverage of rural areas is more costly when using higher frequencies, comparing UMTS to GSM. In addition seasonal and environmental variations are strongest here. The model used was a 3D radar model, comprised of a 2D vertical Tx-Rx-plane component and a 3D components to include off-axis scattering. The latter components are estimated using bistatic radar techniques. The model is able to provide an accurate estimation of the path loss (signal level), and is also able to estimate time dispersion and angular dispersion, taking into account off-axis contributions. Radio frequencies around 2 GHz were selected, as these are the most important frequency bands for 3. generation mobile systems, even though the envisaged approach supports radio planning for GSM 900 and WLAN systems.

A novel approach to the modeling of scattering from random rough surfaces for 3D channel modeling was developed. This amplitude/phase model is simple and accurate compared to conventional models. It makes no inherent assumption about the degree of roughness, making it suited to model all surfaces. The model outperforms the conventional models Plane surface, SPM, Kirchoff and Oren with respect to accuracy by 1.5 to 10 dB depending on the degree of roughness.

An experimental methodology to characterise random rough surfaces was developed. The work characterised natural surfaces such as asphalt, grass, agriculture, and forest, each of them having a different degree of roughness. Variations due to weather and seasonal changes were taken into account. Typical surface height variations estimated were 10 mm for asphalt, 25 mm for grass, 100 mm for ploughed field and 500 mm for forest. Snow reduced the apparent roughness of ploughed field by 50 %, water on grass increased the reflection coefficient by 50 %.

An analysis of the implications of the results on 3D channel modeling was performed using a demonstration model. The analysis included a comparison between 2D and 3D model prediction for different area types and land use classes. Also the prediction sensitivity to seasonal and weather variations and model parameter variations were inspected. A 3D model is necessary when the 2D component is attenuated more than typically 15 dB relative to free space, depending on area and land usage. In the network planning example Lillehammer (N) this attenuation of at least 15 dB existed in 40 % of all locations. Weather and seasonal variations may change the mean predicted value by up to 4-5 dB.

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An, Kyu Hwan. "CMOS RF power amplifiers for mobile wireless communications." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31717.

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Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2010.
Committee Chair: Laskar, Joy; Committee Member: Cressler, John; Committee Member: Kohl, Paul; Committee Member: Kornegay, Kevin; Committee Member: Tentzeris, Emmanouil. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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Chen, Jun, and 陳軍. "Multicode CDMA for high-speed mobile communications." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B30149903.

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Dissertations / Theses on the topic 'Global Systems for Mobile Communications'

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