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Tesi sul tema "Wireless communication systems. Data transmission systems. Radio"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 6 febbraio 2022

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1

Ng, Ka Wai. "Generalized bit and power allocation for single and multi-user OFDM MIMO system in frequency selective fading channel /". View abstract or full-text, 2003. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202003%20NG.

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2

Labuschagne, Adriaan S. "The design of a telemetry system for Grumeti Reserves /". Thesis, Link to the online version, 2006. http://hdl.handle.net/10019.1/2542.

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3

Motahari, Bidgoli Seyed Mohammad Amin. "An Optical Design Configuration for Wireless Data Transmission". FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2439.

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The concept of 2D barcodes is of great relevance for use in wireless data transmission between handheld electronic devices. In a typical setup, any file on a cell phone for example can be transferred to a second cell phone through a series of images on the LCD which are then captured and decoded through the camera of the second cell phone. In this research, a new approach for data modulation in 2D barcodes is introduced, and its performance is evaluated in comparison to other standard methods of barcode modulation. In the proposed method, Orthogonal Frequency Division Multiplexing (OFDM) modulation is used together with Differential Phase Shift Keying (DPSK) over adjacent frequency domain elements to modulate intensity of individual pixels. It is shown that the bit error rate performance of the proposed system is superior to the current state of the art in various scenarios. A specific aim of this study is to establish a system that is proven tolerant to camera motion, picture blur and light leakage within neighboring pixels of an LCD. Furthermore, intensity modulation requires the input signal used to modulate a light source to be positive, which requires the addition of a dc bias. In the meantime, the high crest factor of OFDM requires a lower modulation index to limit clipping distortion. These two factors result in poor power efficiency in radio over fiber applications in which signal bandwidth is generally much less than the carrier frequency. In this study, it is shown that clipping a bipolar radio frequency signal at zero level, when it has a carrier frequency sufficiently higher than its bandwidth, results in negligible distortion in the pass band and most of the distortion power is concentrated in the baseband. Consequently, with less power provided to the optical carrier, higher power efficiencies and better receiver sensitivity will result. Finally, a more efficient optical integrated system is introduced to implement the proposed intensity modulation method which is optimized for radio over fiber applications.

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4

Gurung, Sanjaya. "Integrating environmental data acquisition and low cost Wi-Fi data communication". Thesis, University of North Texas, 2009. https://digital.library.unt.edu/ark:/67531/metadc12131/.

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This thesis describes environmental data collection and transmission from the field to a server using Wi-Fi. Also discussed are components, radio wave propagation, received power calculations, and throughput tests. Measured receive power resulted close to calculated and simulated values. Throughput tests resulted satisfactory. The thesis provides detailed systematic procedures for Wi-Fi radio link setup and techniques to optimize the quality of a radio link.

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5

Kriegler, Wouter. "A fixed-point DSP architecture for software-defined radio". Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/3029.

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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009.
Due to ever evolving wireless communication standards and technologies, the need for more flexible radio terminals are becoming more sought after in order to adapt to these new standards. Software-defined radio offers a solution to this demand. Software-defined radio is a radio communication system where signal processing components that have typically been implemented in hardware are replaced by reconfigurable and re-useable software modules running on a digital processor. The need exists to rapidly create new SDR applications without designing an entire system from the ground up, and without specialised knowledge of the target platform. This thesis initially describes the design of a generic SDR architecture that is highly reconfigurable and promotes a high level of code re-use. The research forms part of a larger project to design a domain-specific language (DSL) in which to describe SDR functionality in a platform-independent way. In this thesis, the code synthesis from the DSL is extended to support the Freescale DSP563xx family.

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6

Rootman, Adriaan Cornelius. "Development of a remote wireless monitoring system for large farms". Thesis, Cape Peninsula University of Technology, 2012. http://hdl.handle.net/20.500.11838/1173.

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Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Electrical Engineering at the Cape Peninsula University of Technology, 2012
This research project addresses the unique challenges of extensive farming in terms of monitoring and controlling remote equipment or events. Poorly maintained roads and escalating fuel costs increase difficulty of farming and the time spent on physically monitoring remote sites further reduces financial yields. The research showed that there are very few solutions that implement wireless or electronic technology to overcome the challenges associated with these isolated and arid areas and that a low-cost, long range wireless telemetry solution that is easy to use would be beneficial for the extensive farming industry. It was therefore the aim of this project to develop a remote monitoring and controlling solution that implements wireless technology to convey information of activities around the farm utilising electronic means. To be able to successfully develop a wireless telemetry solution that will accurately meet the needs of this specific sector of industry, market research was conducted. To guide the research, the QFD (quality function deployment) process for product development has been implemented. The research consisted out of various aspects including a survey, financial considerations and international comparisons. The research also aided in the understanding of the day-to-day activities and also the physical parameters of extensive farms. Also, currently available technologies and products were evaluated to establish whether similarities exist that will aid in the development of a new product. The development process was based on the results obtained in the market research and resulted in a wireless telemetry solution that overcame all the design challenges and proved to be technically feasible, successfully addressing the application requirements. Zigbee technology was utilized for wireless communication because it provided an off-the-shelf solution with a number of readily available development platforms from various technology providers. A communication range of up to 6 kilometres with a transmitted power of 11dBm was achieved for point-to-point communication and a mesh network topology has been implemented for even longer range and complete coverage on farms. Various types of measurements have been catered for, with custom-designed instrumentation which enabled measurements such as water levels, movement and analogue signals. Also, a basic user interface was developed to enable the user to monitor or control the equipment or events remotely from a personal computer, locally or even over the internet. The results of this research project showed that by carefully selecting available technologies and understanding the application, it is possible to develop a solution that addresses the monitoring and controlling needs associated with extensive farming. The wireless telemetry system that was developed resulted in a saving equal to 10% of the total expenses of the farms per year. The telemetry system is therefore a financially feasible solution with a payback period of less than 1 year and far below the initial estimated budget. Without the need to physically monitoring equipment and events, an increase in productivity and the expansion of the overall enterprise is a further benefit added unto the monetary savings. In addition to the financial benefits of implementing new wireless technology, this is an opportunity to contribute to a cleaner and more sustained future as a legacy for the next generation by reducing the carbon footprint of the farm.

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7

Schuartz, Fábio César. "Múltiplas antenas como alternativa para aumentar a taxa de extração de chaves secretas em redes veiculares com desvanecimento lento". Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1797.

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A comunicação em redes veiculares ad hoc (VANETs) é comumente dividida em dois cenários, chamados veículo-a-veículo (V2V) e veículo-a-infraestrutura (V2I). Objetivando estabelecer uma comunicação segura contra espiões, trabalhos recentes tem proposto a troca de chaves secretas baseado na variação da força do sinal recebido (RSS). Entretanto, o bom desempenho de tal método depende da taxa de variação do canal, sendo mais apropriado a cenários em que o canal varia rapidamente, como geralmente é o caso da comunicação V2V. Já na comunicação V2I, o canal normalmente possui desvanecimento lento. Neste trabalho, é proposta a utilização de múltiplas antenas com o intuito de gerar artificialmente um canal de desvanecimento rápido, permitindo assim a extração de chaves secretas através da RSS em um cenário V2I. Análises numéricas mostram que o modelo proposto pode obter desempenho superior, em termos de taxa de extração de bits secretos, do que o modelo de salto em frequência proposto na literatura.
The communication in vehicular ad hoc networks (VANETs) is commonly divided in two scenarios, namely vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I). Aiming at establishing secure communication against eavesdroppers, recent works have proposed the exchange of secret keys based on the variation in received signal strength (RSS). However, the performance of such scheme depends on the channel variation rate, being more appropriate for scenarios where the channel varies rapidly, as is usually the case with V2V communication. In the communication V2I, the channel commonly undergoes slow fading. In this work we propose the use of multiple antennas in order to artificially generate a fast fading channel so that the extraction of secret keys out of the RSS becomes feasible in a V2I scenario. Numerical analysis shows that the proposed model can outperform, in terms of secret bit extraction rate, a frequency hopping-based method proposed in the literature.

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8

Razavi, S. H. "Data transmission over TACS cellular radio". Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329178.

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9

Zhou, Yiqing, e 周一靑. "Advanced techniques for high speed wireless communications". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29296080.

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10

Alastalo, Ari. "Microelectromechanical resonator-based components for wireless communications : filters and transmission lines /". Espoo VTT, 2006. http://www.vtt.fi/inf/pdf/publications/2006/P616.pdf.

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11

Huang, Yuanliang. "Study of advanced techniques in high speed wireless transmissions". Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B36824653.

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12

Huang, Yuanliang, e 黃源良. "Study of advanced techniques in high speed wireless transmissions". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B36824653.

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13

王徐芳 e Xufang Wang. "Multiresolution joint source and channel coding for wireless communications". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31225299.

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14

Yang, Daiqin. "Transmission scheduling in single-hop and multi-hop wireless networks". Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B37319371.

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15

Yang, Daiqin, e 楊代琴. "Transmission scheduling in single-hop and multi-hop wireless networks". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B37319371.

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16

Gurung, Sanjaya Acevedo Miguel Felipe. "Integrating environmental data acquisition and low cost Wi-Fi data communication". [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/ark:/67531/metadc12131.

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17

Nguyen, Anh Van. "Concatenated space-time coding for wireless systems". Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/13533.

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18

Li, Yang. "Models and applications of wireless networks in rural environments". Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&amp.

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Abstract (sommario):

With the unprecedented growth of the communication industry that the world is experiencing, the demand from rural inhabitants for high quality communications at an economically affordable cost is growing. However, rural areas are rather restricted from deploying communication services due to the rough natural environment, and the shortage of rudimentary communication facilities and technical personnel. Appropriate models for building rural wireless networks and a concomitant simulation environment are, therefore, expected to enable the construction of technologically-optimal and economically-efficient networks in specified rural areas.

The research has set up two independent models, one for the economic need and the other for the technical need of building networks in rural areas. One model was the Impact of Telecommunications Model, which disclosed the importance of building a wireless network in specified rural areas by choosing an economic parameter to forecast the profitability of the network. The other was the Service Model, which collected primitive data from given rural areas and abstracted these data by flowing them through four technical layers to form the predicted technical wireless network. Both of the models had been applied to real-world cases to demonstrate how to use them.

A simulation environment was finally designed and implemented to realize the above two models for the sake of instantiation. This environment could simulate the specified rural network by constructing a wireless network on the invented areas and evaluating its quality and economic efficiency. It was written in Scilab simulation language, which was an open source.

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19

Zhou, Lin. "Energy efficient transmitter design with compact antenna for future wireless communication systems". Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33104.

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This thesis explores a novel technique for transceiver design in future wireless systems, which is cloud radio access networks (CRANs) with single radio frequency (RF) chain antennas at each remote radio head (RRH). This thesis seeks to make three contributions. Firstly, it proposes a novel algorithm to solve the oscillatory/unstable behaviour of electronically steerable parasitic array radiators (ESPAR) when it provides multi-antenna functionality with a single RF chain. This thesis formulates an optimization problem and derives closed-form expressions when calculating the configuration of an ESPAR antenna (EA) for arbitrary signals transmission. This results in simplified processing at the transmitter. The results illustrate that the EA transmitter, when utilizing novel closed-form expressions, shows significant improvement over the performance of the EA transmitter without any pre-processing. It performs at nearly the same symbol error rate (SER) as standard multiple antenna systems. Secondly, this thesis illustrates how a practical peak power constraint can be put into an EA transceiver design. In an EA, all the antenna elements are fed centrally by a single power amplifier. This makes it more probable that during use, the power amplifier reaches maximum power during transmission. Considering limited power availability, this thesis proposes a new algorithm to achieve stable signal transmission. Thirdly, this thesis shows that an energy efficiency (EE) optimization problem can be formulated and solved in CRANs that deploy single RF chain antennas at RRHs. The closed-form expressions of the precoder and power allocation schemes to transmit desired signals are obtained to maximise EE for both single-user and multi-user systems. The results show that the CRANs with single RF chain antennas provide superior EE performance compared to the standard multiple antenna based systems.

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20

Lai, Lifeng. "Multiuser wireless networks the user cooperation perspective". Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1186425130.

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21

Sun, Qiong, e 孙琼. "Topology-transparent distributed scheduling in wireless networks". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B44904101.

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22

Kang, Ajay I. S. "Algorithms for reduced content document synchronization". [Gainesville, Fla.] : University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE0000549.

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23

Du, Toit Rene. "Mobile radio data network for documentation display". Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51832.

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Thesis (MScEng)--University of Stellenbosch, 2000.
ENGLISH ABSTRACT: This product is designed as an educational tooL It was developed to make a classroom more organised. Better and easier communication between the teacher and the students can be established, as well as improved communication between different classrooms. The stand alone unit can be used anywhere because there is no wiring between this and the computer. It can be a big addition to the educational system, especially in places where books are not readily available for the students. The system consists of various components. These components are a computer, a stand alone unit and an interconnection for these two. The interconnection was incorporated with the use of radio links. At the computer side of the design, a windows interface was developed to enable the computer user to communicate with the stand alone unit user. The radio link was inserted to make the communication between the computer and the stand alone unit wireless. The stand alone unit consists of a keypad, liquid crystal display, serial port and a floppy drive. The serial port is used as connection between the stand alone unit and the radio links. It is possible to expand the system. The keypad can be replaced by a keyboard to enable the stand alone user to type and save data on the stand alone unit itself, and a hard drive might be added to increase the storage space. The inclusion of the floppy drive makes the system more compact and creates the possibility of transferring data by use of the floppy, which in tum does not limit a person to working only in one place.
AFRIKAANSE OPSOMMING: Hierdieproduk is ontwerp as 'n hulpmiddel vir die onderwys stelsel. Dit is ontwerp om 'n klaskamer meer georganiseerd te maak. Beter en makliker kommunikasie tussen onderwysers en studente word op hierdie manier verseker, asook verbeterde kommunikasie tussen verskillende klaskamers. Die alleenstaande eenheid kan enige plek gebruik word, aangesien daar geen bedrading is tussen die eenheid en die rekenaar nie. Dit kan 'n groot bydrae wees tot die onderwysstelsel, veral in plekke waar boeke nie so alledaags beskikbaar is nie. Die stelsel bestaan uit verskeie komponente. Hierdie komponente is 'n rekenaar, 'n alleenstaande eenheid en 'n verbinding tussen hierdie twee. Die verbinding tussen hierdie twee is met behulp van radio skakels gedoen. By die rekenaar kant van die ontwerp, is 'n rekenaar program geskryf wat die kommunikasie tussen die rekenaar en die alleenstaande eenheid beheer. Die radio skakel is ingesluit in die ontwerp om die kommunikasie tussen die rekenaar en die alleenstaande eenheid draadloos te hou. Die alleenstaande eenheid bestaan uit 'n miniatuur sleutelbord, vloeibare kristal vertoon, 'n serie poort en 'n slapskyf dryf. Die serie poort word gebruik as verbinding tussen die alleenstaande eenheid en die radio skakels. Dit is moontlik om die stelsel te vergroot. Die miniatuur sleutelbord kan vervang word deur 'n standaard sleutelbord om die alleenstaande eenheid gebruiker in staat te stelom data op die eenheid self te tik en te stoor. 'n Hardeskyf kan ook ingevoeg word om die stoor spasie van die stelsel te vergroot. Die insluiting van die slapskyf veroorsaak dat die stelsel meer kompak is en ontwikkel die moontlikheid om die data oor te dra met behulp van die skyf, wat weer 'n persoon in staat stelom op meer as slegs een plek te werk.

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24

李世榮 e Sai-weng Lei. "Adaptive interleaving for orthogonal frequency division multiplexing systems". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31224702.

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25

Hui, Chui Ying. "Broadcast algorithms and caching strategies for mobile transaction processing". HKBU Institutional Repository, 2007. http://repository.hkbu.edu.hk/etd_ra/781.

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26

Abdullah, S. N. "Data transmission at 9600 bit/sec over an HF radio link". Thesis, Loughborough University, 1986. https://dspace.lboro.ac.uk/2134/7432.

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The thesis is concerned with serial data transmission at 9600 bit/sec over a voiceband channel, where the main impairments are additive noise and intersymbol interference, and the latter varles slowly with time. The thesis includes a brief description of the ionospheric propagation medium and presents an equivalent baseband model of the HF channel, suitable for computer simulation of quadrature amplitude modulation (QAM) systems. A study of 16-point QAM signals transmitted over voiceband HF channels is then carr-iod out usj-ng the given channel model. Several cost effective near-maximum-likelihood detection processes have been developed for HF modems. Each detector is here preceded by an adaptive linear filter that is adjusted to make the sampled impulse response of the channel and filter minimum phase. These detectors require an accurate knowledge of the sampled impulse response of the channel, if their full potential is to be achieved. The results of computer-simulation tests on the near-maximum-likelihood detectors are given, where these tests assume that other receiver operations such as channel estimation and adaptive linear filtering, together with element timing synchronisation and Doppler shift correction, are carried out perfectly. A recently developed HF channel estimator employing a simple feedforward transversal-filter and requiring knowledge of the number of skywaves is next investigated and a starting up procedure is developed for such an estimator. The technique is then made fully adaptive in the sense that it continues to operate correctly when the number of skywaves changes. Results of computer simulation tests are then presented showing the performance of the above detectors when operating with a channel estimator and adaptive linear filtering. Finally modem synchronisation is studied and various techniques of element timing and carrier frequency synchronisation are proposed.

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27

Spencer, Quentin H. "Transmission Strategies for Wireless Multi-user, Multiple-Input, Multiple-Output Communication Channels". Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd378.pdf.

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28

Khan, Nabeel Pervaiz. "Energy efficient communication and rate control algorithms for wireless sensor networks". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 114 p, 2009. http://proquest.umi.com/pqdweb?did=1818417511&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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29

Chen, Cheng. "Simultaneous transmission of baseband signal and in band RF signal". Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708805.

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30

Sun, Songsong. "High data rate transmission in multi-service code division multiple access wireless communication systems". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0004/NQ39596.pdf.

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31

Funk, James C. "Rate-adaptive runlength limited encoding for high-speed infrared communication /". Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd1025.pdf.

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32

Sharkey, Jeffrey Allen. "Automated radio network design using ant colony optimization". Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/sharkey/SharkeyJ0508.pdf.

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Abstract (sommario):

Radio networks can provide reliable communication for rural intelligent transportation systems (ITS). Engineers manually design these radio networks by selecting tower locations and equipment while meeting a series of constraints such as coverage, bandwidth, maximum delay, and redundancy, all while minimizing network cost. As network size and constraints grow, the design process can quickly become overwhelming. In this thesis we model the network design problem (NDP) as a generalized Steiner tree-star (GSTS) problem. Any solution to the minimum Steiner tree (MST) problem on a constructed GSTS graph will directly identify the tower locations and equipment needed to build the network at an optimal cost. The direct MST solution can only satisfy coverage constraints. Because the MST problem is known to be NP-hard, our research applies ant colony optimization (ACO) to find near-optimal MST solutions. Using ACO also allows us to meet bandwidth, maximum delay, and redundancy constraints. We verify that our approach finds near-optimal designs by comparing it against a 2-approximation algorithm in several different scenarios.

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33

Wang, Li, e 王立. "Channel adaptive fair queueing in wireless packet data networks". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31226802.

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34

盧志明 e Chi-ming Lo. "Analytical evaluation of wireless digital communication performance over fading channels". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B3124208X.

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35

Lo, Ernest Sze-Yuen. "Differential OFDM with iterative detection and signal space diversity for broadband wireless communication /". View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202002%20LO.

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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002.
Includes bibliographical references (leaves 67-69). Also available in electronic version. Access restricted to campus users.

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36

Gong, Yi. "Space-time coding for high data-rate wireless communications over space and frequency selective fading channels /". View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202002%20GONG.

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Abstract (sommario):

Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2002.
Includes bibliographical references (leaves 105-114). Also available in electronic version. Access restricted to campus users.

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37

Chang, Yong Jun. "Design of concurrent cooperative transmission systems on software-defined radios". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50360.

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Concurrent cooperative transmission (CCT) occurs when a collection of power-constrained single-antenna radios transmit simultaneously to form a distributed multi-input and multi-output (DMIMO) link. DMIMO can be a means for highly reliable and low-latency cooperative routing, when the MIMO channel is exploited for transmit and receive diversity; in this context, the range extension benefit is emphasized. Alternatively, DMIMO can be a means for high-throughput ad hoc networking, when the MIMO channel is used with spatial multiplexing. In both cases, concatenated DMIMO links are treated. The key contribution of this dissertation is a method of pre-synchronization of distributed single-antenna transmitters to form a virtual antenna array, in the absence of a global clock, such as a global positioning system (GPS) receiver or a network time protocol (NTP) to provide reference signals for the synchronization. Instead, the reference for synchronization comes from a packet, transmitted by the previous virtual array and simultaneously received by all the cooperative transmitters for the next hop. The method is realized for two types of modulation: narrowband non-coherent binary frequency-shift keying (NCBFSK) and wideband orthogonal frequency division multiplexing (OFDM). The pre-synchronization algorithms for transmission are designed to minimize the root-mean-square (RMS) transmit time, sampling and carrier frequency error between cooperative transmitters, with low implementation complexity. Since CCT is not supported by any existing standard or off-the-shelf radios, CT must be demonstrated by using software-defined radios (SDRs). Therefore, another contribution is a fully self-contained and real-time SDR testbed for CCT-based networking. The NCBFSK and OFDM systems have been designed and implemented in C++ and Python programming languages in the SDR testbed, providing practical performance of the CCT-based systems.

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38

Ramachandran, Anil. "Diversity techniques for signal-strength based indoor location determination". Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.umr.edu/thesis/pdf/Ramachandran_09007dcc803c0f44.pdf.

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Thesis (M.S.)--University of Missouri--Rolla, 2007.
Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed May 4, 2007) Includes bibliographical references.

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Huang, Defeng. "Low complexity diversity combining and carrier frequency offset compensation for ubiquitous OFDM based broadband wireless communications /". View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202004%20HUANG.

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Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2004.
Includes bibliographical references (leaves 163-171). Also available in electronic version. Access restricted to campus users.

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Yu, Sam Shaokai. "Performance analysis and call control procedures in high-speed multimedia personal wireless communications /". Title page, abstract and contents only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phy936.pdf.

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41

Huang, Yan-Yu. "CMOS-based amplitude and phase control circuits designed for multi-standard wireless communication systems". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44908.

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Designing CMOS linear transmitter front-end, specially the power amplifiers (PAs), in multi-band wireless transceivers is a major challenge for the single-chip integration of a CMOS radio. In some of the linear PA systems, for example, polar- or predistortion-PA system, amplitude and phase control circuits are used to suppress the distortion produces by the PA core. The requirements of these controlling circuits are much different from their conventional role in a receiver or a phase array system. In this dissertation, the special design issues will be addressed, and the circuit topologies of the amplitude and phase controllers will be proposed. In attempt to control the high-power input signal of a PA system, a highly linear variable attenuator with adaptive body biasing is first introduced. The voltage swing on the signal path is intentionally coupled to the body terminal of the triple-well NMOS devices to reduce their impedance variation. The fabricated variable attenuator shows a significant improvement on linearity as compared to previous CMOS works. The results of this research are then used to build a variable gain amplifier for linear PA systems that requires gain of its amplitude tuning circuits. Different from the conventional attenuator-based VGAs, the high linearity of the suggested attenuator allows it to be put after the gain stage in the presented VGA topology. This arrangement along with the current boosting technique gives the VGA a better noise performance while having a linear-in-dB tuning curve and better worst-case linearity. The following part of the dissertation is about a compact, linear-in-degree tuned variable phase shifter as the phase controller in the PA system. This design uses a modified RC poly-phase filter to produce a set of an orthogonal phase vectors with smaller loss. A specially designed control circuit combines these vectors and generates an output signal with different phases, while having very small gain mismatches at different phase setting. The proposed amplitude and phase control circuits are then verified with a system level analysis. The results show that the proposed designs successfully reduce the non-linear effect of a wireless transmitter.

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42

Wang, Xiangyang, e 王向陽. "Transmit diversity in CDMA for wireless communications". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31246072.

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43

Soundararajan, Srivathsan Agrawal Prathima. "Scheduling in WiMAX based wireless networks". Auburn, Ala, 2008. http://hdl.handle.net/10415/1449.

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44

Hernandez, Edwin A. "Adaptive networking protocol for rapid mobile environments". [Gainesville, Fla.] : University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE1001150.

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45

Kim, Eung Jung. "Highly efficient supply modulator for mobile communication systems". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41058.

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Switching frequency modulation techniques, an inductor current sensing circuit for fast switching converter, and a dual converter are proposed, and the simulation results and experimental results are drawn. The experimental results for monotonic and pseudo-random modulation techniques show that the switching noise peak was effectively reduced as much as -19 dBc. The inductor current sensing circuit accurately tracks the output current of the switching converter that switches up to 30MHz. This current sensing circuit is used to drive the slow converter in the dual converter. The dual converter consists of a fast converter and a slow converter. The fast converter provides only the high frequency conponents in the output current, and the slow converter provides the majority portion of the output current with a higher efficiency. Therefore, the dual converter can have a fast transient response without sacrificing its efficiency. All chips are fabricated in a standard CMOS 0.18um process.

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46

Li, Hongxing, e 李宏兴. "Optimal data dissemination in stochastic and arbitrary wireless networks". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B4832971X.

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Data dissemination among wireless devices is an essential application in wireless networks. In contrast to its wired counterparts which have more stable network settings, wireless networks are subject to network dynamics, such as variable network topology, channel availability and capacity, which are due to user mobility, signal collision, random channel fading and scattering, etc. Network dynamics complicate the protocol design for optimal data disseminations. Although the topic has been intensively discussed for many years, existing solutions are still not completely satisfactory, especially for stochastic or arbitrary networks. In this thesis, we address optimal data dissemination in both stochastic and arbitrary wireless networks, using techniques of Lyapunov optimization, graph theory, network coding, multi-resolution coding and successive interference cancellation. We first discuss the maximization of time-averaged throughput utility over a long run for unicast and multirate multicast, respectively, in stochastic wireless networks without probing into the future. For multi-session unicast communications, a utility-maximizing cross-layer design, composed of joint end-to-end rate control, routing, and channel allocation, is proposed for cognitive radio networks with stochastic primary user occupations. Then, we study optimal multirate multicast to receivers with non-uniform receiving rates, also making dynamic cross-layer decisions, in a general wireless network with both a timevarying topology and random channel capacities, by utilizing random linear network coding and multi-resolution coding. In both solutions, we assume users are selfish and prefer only to relay data for others with strong social ties. Such social selfishness of users is a new constraint in network protocol design. Its impact on efficient data dissemination in wireless networks is largely unstudied, especially under stochastic settings. Lyapunov optimization is applied in our protocol design achieving close-to-optimal utilities. Next, we turn to latency-minimizing data aggregation in wireless sensor networks having arbitrary network topologies under the physical interference model. Different from our effort for stochastic networks where we target at time-averaged optimality over a long run, the objective here is to minimize the time-span to accomplish one round of aggregation scheduling for all sensors in an arbitrary topology. This problem is NP-hard, involving both aggregation tree construction and collision-free link scheduling. The current literature mostly considers the protocol interference model, which has been shown to be less practical than the physical interference model in characterizing the interference relations in the real world. A distributed solution under the physical interference model is challenging since cumulative interferences from all concurrently transmitting devices need to be well measured. In this thesis, we present a distributed aggregation protocol with an improved approximation ratio as compared with previous work. We then discuss the tradeoff between aggregation latency and energy consumption for arbitrary topologies when the successive interference cancellation technique is in force. Another distributed algorithm is introduced with asymptotic optimality in both aggregation latency and latency-energy tradeoff. Through theoretical analysis and empirical study, we rigorously examine the optimality of our protocols comparing with both the theoretical optima and existing solutions.
published_or_final_version
Computer Science
Doctoral
Doctor of Philosophy

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47

Daempfling, Hauke C. "Design and implementation of the precision personnel locator digital transmitter system". Link to electronic thesis, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-122006-161049/.

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Thesis (M.S.)--Worcester Polytechnic Institute.
Keywords: precision personnel locator; digital systems; embedded systems; waveform generation; data communication. Includes bibliographical references (leaves 108-110).

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48

Kannan, Arumugam. "Communication Strategies for Single-User and Multiuser Slow Fading Channels". Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19850.

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Technological progress in the field of wireless communications over the past few years has only been matched by the increasing demand for sophisticated services at lower costs. A significant breakthrough was achieved in the design of efficient wireless communication systems with the advent of the diversity concept. Spatial diversity exploits the availability of multiple spatial paths between the transmitter and receiver by placing antenna arrays at either end. In addition to improving the reliability of communication by creating redundant copies of the transmitted information at the receiver, wireless transceivers with multiple antennas exploit the spatial degrees of freedom to multiplex multiple streams of data and achieve significant gains in spectral efficiencies. In this thesis, we design spatial diversity techniques for slow-fading wireless channels. There are two parts to this thesis: In Part I we propose spatial diversity techniques for point-to-point single-user wireless systems, while in Part II we propose multiuser cooperative diversity techniques for multiuser wireless communication systems. In the first part, we propose a set of new wireless communication techniques for multiple-input, multiple-output (MIMO) channels over Rayleigh slow-fading wireless channels. We introduce MIMO transceivers that achieve high data rates and low error rates using a class of MIMO systems known as layered space-time (ST) architectures, which use low complexity, suboptimal decoders such as successive cancellation (SC) decoders. We propose a set of improved layered space-time architectures and show that it is possible to achieve near-optimal error performance over MIMO channels while requiring just SC decoding at the receiver. We show that these architectures achieve high rate and diversity gains. We also show that some of the proposed layered space-time architectures could find applications in multiple-access communications as low-complexity solutions for achieving near-optimum performance. In the second part of this thesis, we propose novel techniques for cooperative communication between terminals in multiuser wireless communication systems. Cooperative communication is a concept where neighboring terminals share their antennas and signal processing resources to create a virtual transmit array . In addition to transmitting their own information, users in a cooperative communication system listen to transmission from other users and relay this information to the destination, thus creating multiple paths between transmitter and receiver. This form of diversity, known as cooperative diversity, helps improve the overall reliability of all the users in a network. We start with a simple three node multiple-access system where two users are communicating with a common destination. We propose new high-rate cooperation strategies which achieve the full diversity gain offered by the cooperative channel for this simple system. We propose a new framework to address the tradeoff between cooperation and independent transmission over a multiple access channel and determine the conditions under which each idea is better than the other. Finally, we propose a high rate cooperation protocol which achieves the maximum diversity over a multiple access system with an arbitrary number of users and achieves high rates which scale favorably as the number of users increases.

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49

Jordão, Marina Daniela da Cruz. "Characterization systems for RFID applications". Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/16324.

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Mestrado em Engenharia Eletrónica e Telecomunicações
This dissertation has the collaboration of the Telecommunications Institute with National Instruments, in order to develop solutions for characterization and measurement for RF-DC converters. These characterization solutions are intended to ensure optimization of this type of circuit, which is the basis of Wireless Power Transmission and Electromagnetic Energy Harvesting systems. It is intended to use LabVIEW code and the PXI modules from NI with the goal of extrapolating these measurement systems to read and measure the RFID Tags. Therefore, this dissertation is focused on RFID characterization using the LabVIEW, in other words, RFID reader.
Esta dissertação surge no âmbito da colaboração do Instituto de Telecomunicações com a National Instruments (NI), com o intuito de desenvolver soluções de caracterização e medida para conversores RF-DC. Estas soluções de caracterização pretendem garantir uma optimização deste tipo de circuitos, que é a base dos sistemas de Wireless Power Transmission and Electromagnetic Energy Harvesting. Pretende-se assim recorrer a código Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) e aos módulos PCI eXtensions for Instrumentations (PXI) da NI com o objetivo extrapolar estes sistemas de medida para aplicação de leitura e medida de Tags Radio Frequency Identification (RFID). Assim sendo, nesta dissertação pretende-se desenvolver um sistema de caracterização do RFID usando o LabVIEW, ou seja, um leitor de RFID.

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50

Ragadza, Ntakadzeni Ronald. "Slotted time based protocol and polling strategies for low speed, narrow band applications". Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50093.

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Thesis (MScEng)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: This thesis investigates and develops some aspects of low speed wireless telemetry applications. The system configuration is one of a single master, controlling and communicating with multiple slave stations over a radio network. The aim of this thesis is to develop a narrow band wireless communications network based on a protocol with slotted time base, utilizing standard, off the shelf hardware. The idea is to investigate different strategies for improvement of data throughput performance under conditions of both low- and high loading, using this basic protocol. Such strategies may, amongst others include collision detection, flow control and pre-scheduling algorithms. This thesis will also show the how the non-adaptive system's data throughput performance can be improved using an adaptive system under low- and high loading. Half-duplex communication mode will be used for data communication.
AFRIKAANSE OPSOMMING: Hierdie tesis ondersoek en ontwikkel sommige aspekte van laespoed radiotelemetrie toepassings. Die stelselkonfigurasie is een van 'n enkel meesterstasie wat met 'Il aantal buitestasies kommunikeer oor 'n radionetwerk. Die doel van die tesis is om 'n tydgegleufde protokol te ontwikkel vir nouband radiotoepassings, deur gebruik te maak van standaard, maklik beskikbare hardeware. Die doel is om verskillende benaderings te ondersoek vir die verbetering van datadeurset onder toestande van beide hoë- en lae belading. Sulke strategieë mag botsingsdeteksie, vloeibeheer en voor-skedulering insluit. Die tesis salook aandui hoe die data deurset van die nie-aanpasbare metode verbeter kan word, deur gebruik te maak van 'n aanpasbare metode vir beide beladingstipes. Die kommunikasiestelsel is half-dupleks gebaseer.

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