Dissertations / Theses: 'Mobile communication systems Forecasting'

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Cosgrove, Stephen Richard. "Mobile data services adoption in New Zealand future predictions : a thesis submitted to the graduate faculty of Design and Creative Technologies, Auckland University of Technology, School of Computer and Information Sciences in partial fulfilment of the requirements for the degree of Master of Computing Information Systems, Auckland, New Zealand, 2007." Click here to access this resource online, 2007. http://hdl.handle.net/10292/402.

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Thesis (MCIS - Computer and Information Sciences) -- AUT University, 2007.
Includes bibliographical references. Also held in print (xii, 100 leaves : ill. ; 30 cm.) in the Archive at the City Campus (T 384.5 COS)

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Imsuksri, Sumit. "Mobile order entry system based on the wireless technology." CSUSB ScholarWorks, 2002. https://scholarworks.lib.csusb.edu/etd-project/2265.

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The sales representatives primary duties are to attract wholesale and retail buyers and purchasing agents to their merchandise, and to address any of their client's questions or concerns. Aided by a laptop computer connected to the Internet, they can access the customer information and sell products to their customer immediately. This project, a Mobile Order Entry System using cellphones, will give sales representatives as state-of-the-art alternative in accessing anf selling products to their customers through cell phones instead of using laptop computers.

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Hjelm, Daniel, Emanuel Wreeby, and Anton Sjöström. "Aggregation and power forecasting for the CoordiNet power flexibility market in Uppsala." Thesis, Uppsala universitet, Institutionen för materialvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-445610.

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In the region of Uppland, a shortage of electric power during cold days has emerged during the past years by virtue of the electrification of the society and industry in general. As a result, a power flexibility market managed by the CoordiNet project has commenced to hopefully create a more reliant, eco-friendly and accessible electricity supply. Uppsala kommun wishes to participate in the market but needs a solution for communication between market and technology and smart control methods. In this project, the solution to the problem, consisting of a mobile app, API, database, server and deep learning model, almost meets the requirements to participate on the market this autumn. With more time and resources, the product can hopefully be completed, enabling both economic and city growth in the region.

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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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Ma, Ming. "Multiuser mobile communication systems." Thesis, Lancaster University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289069.

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Schworer, William Joseph. "Nationwide mobile communication systems." Thesis, Monterey, California. Naval Postgraduate School, 1990. http://hdl.handle.net/10945/37533.

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Approved for public release; distribution unlimited.
This thesis provides a basic understanding of nationwide terrestrial and satellite mobile communications and tracking technologies. Covered are systems currently available and in development. An analysis of user costs is performed for comparison. A more detailed mobile satellite cost/benefit analysis for use by the trucking industry is also presented. Follow-on chapters contain discussions of the basic economic issues faced by satellite system operators and the regulatory history of mobile satellite services. Contained in the appendices are a more detailed discussion of mobile satellite systems and a layman's explanation of communication and navigation technologies. The conclusion presents comments on the possible future direction of these new mobile communication services and makes recommendations for trucking industry use.

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Phongphanphanee, Chai. "Multilayer mobile communication systems." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324001.

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Tufekcioglu, Refik. "Communication models in mobile computing systems and mobile agents." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA378775.

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Thesis (M.S. in Computer Science) Naval Postgraduate School, March 2000.
Thesis advisor(s): Michael, James B. "March 2000." Includes bibliographical references (p. 131-137). Also available in print.

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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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Arkhipov, Alexander. "IFDMA for uplink mobile radio communication systems." München Utz, 2010. http://deposit.d-nb.de/cgi-bin/dokserv?id=3440635&prov=M&dokv̲ar=1&doke̲xt=htm.

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Chen, Liang. "Survey of Mobile Communication Systems and Handover." Thesis, Linköping University, Department of Electrical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-12002.

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After more than two decades’ development, modern mobile cellular networks now have almost approached to the commercial level of fourth generation communication networks. For each of the mobile solutions, there are special attributes but also similarities compared to the other competitive solutions. We can also find relationships between the old generation solutions and the inheritors or innovations.

During the communicating session using any kind of existing mobile handset, the handover procedure is a very important one that may effect connection quality and also the phone call continuity. Nowadays, the mobile cellular networks have a trend to interact with LAN networks. They will co-exist and work together to support higher data rate over a wider coverage. Seamless handover proposals like Unlicensed Mobile Access (UMA) can support the heterogeneous handover between Global System for Mobile Communications (GSM) and Wireless (Wi-Fi) Network. Several Media Independent Handover (MIH) proposals can handle the vertical handover in the hybrid mobile data network environment such like between wireless local area network (WLAN) and Universal Mobile Telecommunications System (UMTS) by different solutions.

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Parviainen, Roland. "Large scale and mobile group communication systems." Doctoral thesis, Luleå tekniska universitet, Datavetenskap, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26688.

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This doctoral thesis examines different attributes of large scale group communication systems such as scalability, security and mobility by studying two different prototype systems - mIR (multicast Interactive Radio) and MES (Mobile E-meeting Services). mIR is a system for large scale real-time music distribution, designed as an interactive radio system for the Internet. MES is a collection of tools for improving the use of e-meeting and video conferencing tools in a mobile environment. The mIR prototype has been used to study scalability and security. Scalability in mIR concerns how to support as many users as possible without degrading the experience. This is achieved using IP multicast together with algorithms that limits the bandwidth usage regardless of the number of users. The work on security have focused on copy prevention through digital watermarking. By adding a unique watermark, i.e. a fingerprint, to each media copy a pirated copy can be traced back to a specific user, which can act as a deterrent. The thesis shows how we can combine the different goals of fingerprinting and IP-multicast while still maintaining the scalability features of multicast. Many issues need to be considered if e-meetings and video conferencing will become widespread and popular. Scalability and security, discussed in the first part of the thesis are two examples, and the second part of the thesis tries to address a third issue: mobility. In particular we are interested in enabling access to an e-meeting in a mobile environment, where we often have difficult conditions such as bad network connections, the user only have access to the Internet through a web browser or the available devices are small and limited. In many cases it is currently impossible to participate in an e-meeting when you're not in the office. The prototype system developed in the second part of the thesis aims to enable participation from any location and device that have some sort of Internet connection. We try to achieve this by allowing a mobile user to access an e-meeting session from a web browser or from a Java enabled mobile phone. Further, the system makes it possible to review missed events in an e-meeting as it is likely that there are many times where no Internet connection at all is available. The general style of work has been prototype driven with a goal of creating usable prototypes - i.e. the prototypes should be easy to deploy and it should be possible to use and test the prototypes daily. Most the prototypes described in this thesis have indeed been deployed and have seen daily use.

Godkänd; 2005; 20061004 (ysko)

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Zapata, Augusto J. "Analysis of maritime mobile satellite communication systems." Thesis, Monterey, California. Naval Postgraduate School, 1988. http://hdl.handle.net/10945/22890.

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Leelaratne, D. R. V. "Printed antennas for mobile satellite communication systems." Thesis, University of Kent, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369608.

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SOUZA, RODOLFO SABOIA LIMA DE. "POWER CONTROL IN CELULAR MOBILE COMMUNICATION SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4098@1.

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Este trabalho examina várias técnicas de alocação de canais, e alocação de potência, baseados no parâmetro relação sinal ruído interferência. Os esquemas de controle de potência que utilizam este parâmetro, são resolvidos a partir da determinação do raio espectral de uma matriz obtida a partir da manipulação da matriz de ganhos de enlace. Foi provado que é possível resolver esta matriz por outro método baseado em determinantes, e também foi mostrado que este método permite se obter rapidamente uma alocação de canais factível. Além disso, várias técnicas de otimização da alocação de potência foram estudadas, ampliando a abordagem para uma visão completa do problema de alocação de potência.
This work examines several techniques of allocation of canals, and allocation of power, based in the parameter relation signal noise interference. The projects of power control that use this parameter, are decided from the determination of the spectral ray of a matrix gotten from the manipulation of the matrix of profits of enlace. It was proven that it is possible to solve this matrix through another method based on determinative, and also was shown that this method allows to get a feasible allocation of canals quickly. Moreover, several techniques of otimization of the power allocation had been studied, extending the boarding for a complete vision of the problem of power allocation.

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Aggarwal, Pankaj. "Mobile authentication in wireless systems." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010839.

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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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Douglas, Mark Gordon. "Antennas for personal communication systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0005/NQ34257.pdf.

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Hartigan, Patrick Francis. "Forecasting of radiowave attenuation on earth-space links." Thesis, Coventry University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332325.

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Beyene, Dereje, and Befkadu Degefa. "Adaptive Antenna Arrays for Satellite Mobile Communication Systems." Thesis, Linnaeus University, School of Computer Science, Physics and Mathematics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-191.

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Adaptive antenna arrays have a great importance in reduction of the effect of interference and increase the capacity for the mobile satellite communication. Interference and multipath fading remain a main problem for reception of signals. These two problems obviously affect the overall capacity. Adaptive antenna arrays in the handheld mobile apparatus will be the solution for the above two problems.

Satellite mobile communication is one of the growing fields in the communication area where terrestrial infrastructures are unable or ineffective to supply. Maritime, aeronautical and land mobile are some of the applications. During natural disasters where ground services are stopped, mobile satellite communications has great importance. Following the hurricane season, the Asian Tsunami and the devastating Haiti earthquake, mobile satellite communications had played a great role to fill the communication gaps. The satellites can be tracked automatically by adaptive antenna array when it moves in its orbital plane.

In this thesis the methods that how the adaptive antenna array combats interferers is presented and simulated using MATLAB software. The performance of the adaptive antenna array is evaluated by simulating the directivity pattern of the antenna and Mean Square Error (MSE) graph for different scenario like Signal to Interference Noise ratio (SINR), number of iterations, antenna array elements and convergence factor (μ), assuming the signals are coming from different Direction of Arrival (DOA).

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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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Hashimi, Seyed Bahauddin. "Coded modulation techniques for digital mobile communication systems." Thesis, Staffordshire University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321787.

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Economou, Lazaros. "Circular microstrip patch antennas for mobile communication systems." Thesis, University of Kent, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242815.

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Mazharov, Konstantin. "Optimisation of spectrum utilisation for mobile communication systems." Thesis, De Montfort University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366624.

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Park, DongGook. "Cryptographic protocols for third generation mobile communication systems." Thesis, Queensland University of Technology, 2001.

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Foster, Howard Mark Jameson. "High capacity cellular mobile radio systems." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301208.

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Lee, Chin-Chun. "CDMA for cellular mobile radio systems." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240979.

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Güichal, Guillermo Edgardo. "Service location architectures for mobile ad-hoc networks." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/14728.

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Vergara, Alonso Ekhiotz Jon. "Exploiting Energy Awareness in Mobile Communication." Licentiate thesis, Linköpings universitet, Programvara och system, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-98656.

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Although evolving mobile technologies bring millions of users closer to the vision of information anywhere-anytime, device battery depletions hamper the quality of experience to a great extent. The massive explosion of mobile applications with the ensuing data exchange over the cellular infrastructure is not only a blessing to the mobile user, but also has a price in terms of rapid discharge of the device battery. Wireless communication is a large contributor to the energy consumption. Thus, the current call for energy economy in mobile devices poses the challenge of reducing the energy consumption of wireless data transmissions at the user end by developing energy-efficient communication. This thesis addresses the energy efficiency of data transmission at the user end in the context of cellular networks. We argue that the design of energy-efficient solutions starts by energy awareness and propose EnergyBox, a parametrised tool that enables accurate and repeatable energy quantification at the user end using real data traffic traces as input. EnergyBox abstracts the underlying states for operation of the wireless interfaces and allows to estimate the energy consumption for different operator settings and device characteristics. Next, we devise an energy-efficient algorithm that schedules the packet transmissions at the user end based on the knowledge of the network parameters that impact the handset energy consumption. The solution focuses on the characteristics of a given traffic class with the lowest quality of service requirements. The cost of running the solution itself is studied showing that the proposed cross-layer scheduler uses a small amount of energy to significantly extend the battery lifetime at the cost of some added latency. Finally, the benefit of employing EnergyBox to systematically study the different design choices that developers face with respect to data transmissions of applications is shown in the context of location sharing services and instant messaging applications. The results show that quantifying energy consumption of communication patterns, protocols, and data formats can aid the design of tailor-made solutions with a significantly smaller energy footprint.

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Sowerby, Kevin W. "Outrage probability in mobile radio systems." e-Thesis University of Auckland, 1989. http://hdl.handle.net/2292/2516.

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Feldmann, Valerie. "Leveraging mobile media : cross-media strategy and innovation policy for mobile media communication /." Heidelberg [u.a.] : Physica-Verl, 2005. http://www.loc.gov/catdir/enhancements/fy0663/2005920593-d.html.

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Sampath, Latha. "Wireless/mobile video delivery architecture." [Gainesville, Fla.] : University of Florida, 2000. http://etd.fcla.edu/etd/uf/2000/ane5968/thesis.pdf.

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Thesis (M.S.)--University of Florida, 2000.
Title from first page of PDF file. Document formatted into pages; contains x, 78 p.; also contains graphics. Vita. Includes bibliographical references (p. 76-77).

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Wang, Xiaoxiao Sherry. "Qos management for video delivery over mobile wireless networks." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/13856.

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Wassell, Ian J. "Digital mobile radio." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277683.

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Ho, Philip Shiu Wai. "Structural intermodulation interference in mobile radio systems." Thesis, City University London, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305174.

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Boitnott, Brad P. "Maintaining high availability in distributed mobile systems." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Sep/09Sep%5FBoitnott.pdf.

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Thesis (M.S. in Computer Science)--Naval Postgraduate School, September 2009.
Thesis Advisor(s): Singh, Gurminder ; Gibson, John H. "September 2009." Description based on title screen as viewed on November 05, 2009. Author(s) subject terms: High Availability, Failsafe, Fault-tolerant, Distributed Mobile System, TwiddleNet Includes bibliographical references (p. 53-55). Also available in print.

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Lee, Kok Thong. "Performance analysis of Mobile Ad Hoc Networking routing protocols /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Dec%5FLee%5Kok.pdf.

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Kwok, Wing Pong William. "A variety of queueing models for mobile communication systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0006/MQ46077.pdf.

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Zheng, Zhihua, and 鄭智華. "Dynamic channel assignment for cellular mobile radio communication systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31246333.

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Huang, Luan. "Multicast resource management for next generation mobile communication systems." Thesis, University of Surrey, 2006. http://epubs.surrey.ac.uk/804477/.

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NUNES, WALDIR GALLUZZI. "PLANNING OF THIRD GENERATION MOBILE COMMUNICATION SYSTEMS (WCDMA-FDD)." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2002. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=2764@1.

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Os sistemas de comunicações móveis celulares de terceira geração trazem a promessa de oferta de serviços diversos e avançados de comunicação. Estes serviços implicam em requisitos heterogêneos de desempenho da comunicação, e na conseqüente influência de diferentes parcelas de carga sobre a infra-estrutura empregada. Este trabalho contempla a questão do planejamento, dado que pode haver cargas heterogêneas simultâneas, e avalia fatores relacionados à carga, propondo uma ferramenta para modelá-la estatisticamente, de forma que se possa escolher raios de célula apropriados como subsídio à atividade de planejamento.
Third generation mobile communication systems bring the promise of several and advanced communication services, which implies in heterogeneous performance requirements and consequent influence of diferent weighted loads over the communication infra-structure aplyed. This work treats the planning issue, given that there can be heterogeneous simultaneous loads, evaluating factors relateds to this loads and proposing a tool for its tatistical modeling, which allows to choose apropriated cell rays in aid of planning procedures.

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Ring, Christoffer. "Detection and Classification of Interference in Mobile Communication Systems." Thesis, Linköpings universitet, Kommunikationssystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-123507.

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The usage of wireless technology has in the past decade vastly increased and it continues to do so as well. Because of this, we become more and more reliant on this considerably fragile technology. Wireless technology, which uses radio waves to transmit data from one point to another can easily be interfered by radio jammers. This thesis work is about the detection and classification of the interference that is produced by jammers over the Global System for Mobile Communications (GSM) air interface. A typical GSM jammer that can be found on the Internet is analyzed but also more advanced GSM jammers are analyzed. The GSM standard is analyzed to find vulnerabilities that a jammer can take advantage of. The result is an interference detector that can be used to detect and classify interference over the GSM networks. The detector is constructed with an Universal Software Radio Peripheral (USRP) but is also portable to other software-defined radio (SDR) platforms.

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Liu, Yajian. "Radio resource management for next generation mobile communication systems." Thesis, University of Surrey, 2008. http://epubs.surrey.ac.uk/844597/.

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Multi-hop and multi-carrier communication techniques have attracted enormous interest from both industry and academia recently, and have been envisioned very promising for the next generation mobile systems to fulfil their ambitious coverage and capacity goals. In comparison to conventional mobile networks, the radio resource management in the context of multi-hop and multi-carrier communications is generally much more complicated, due to the facts that extra components have to be introduced, and strong inter-dependency is envisioned between these components and the rest of the allocation function. The radio resource management is crucial to ensuring the benefits of multi-hop and multi-carrier transmissions, and hence warrants careful investigations. Nevertheless, it has not yet been fully explored in the literature. In our work, firstly, the radio resource allocation for single-carrier Multi-hop Cellular Networks (MCNs) is investigated. The throughput-maximization problem is formulated mathematically and proven to be NP (Non-deterministic Polynomial)-hard. Considering the prohibitive complexity of finding the optimal solution for such an NP-hard problem, we propose an efficient heuristic algorithm, named Integrated Radio Resource Allocation (IRRA), to find sub-optimal solutions. To prove the effectiveness of the proposed IRRA algorithm, a case study was carried out based on HSUPA (High Speed Uplink Packet Access) with fixed relay stations. The IRRA is evaluated through system level simulations, and compared with two other cases: 1) non-relaying, 2) relaying with a benchmark approach. The results show that the proposed algorithm can ensure significant gains in terms of cell throughput. Following the above studies, the radio resource allocation problem for OFDMA (Orthogonal Frequency Division Multiple Access)-based single-hop systems is studied. The constrained throughput-maximization radio resource allocation problem is formulated and linearized. Its NP-hardness proof is then given by reducing the problem into a classical NP-hard problem, namely Multiple Choice Knapsack Problem (MCKP). A novel mathematical analysis on the problem is then earned out based on its similarity to the MCKP, and an efficient heuristic algorithm, named Integrated Sub-carrier, Bit, and Power Allocation (ISBPA), is proposed to find sub-optimal solutions for it. The proposed algorithm is evaluated through system level simulations and compared to benchmark algorithms. The results show that the proposed ISBPA algorithm can ensure considerable gains in terms of cell throughput and user satisfaction ratio. Finally, the studies in the above two steps are merged and further developed into a complete radio resource allocation algorithm for OFDMA-based MCNs. Evaluation results show significant gains in terms of cell throughput and user satisfaction ratio compared to benchmark algorithms.

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Zhang, Y. "Timing and frequency synchronization for multicarrier mobile communication systems." Thesis, University of Surrey, 2007. http://epubs.surrey.ac.uk/844076/.

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In this thesis, we study the timing and frequency synchronization and channel estimation for multicarrier mobile communication systems. Two typical multicarrier systems, MC-CDMA and OFDMA are considered. The sensitivity of multicarrier systems to the timing and frequency offsets are studied, and system performance is deduced by analytical methods. Analysis shows that both MC-CDMA and OFDMA are very sensitive to the timing and frequency offsets. The OFDMA system with the subband-based subcarrier assignment scheme is more sensitive to the synchronization errors of the reference user than that with interleaved subcarrier assignment scheme, while less sensitive to the synchronization errors of the interference users. We investigate the timing and frequency synchronization methods for multicarrier systems in both the downlink and uplink transmissions. The uplink case is more challenging because the uplink synchronization has to cope with independent frequency and timing offsets for each individual user. A novel timing and frequency offset estimation scheme for the uplink is proposed exploiting the principle of best linear estimation. The timing and frequency offsets are estimated by identifying the differential phases of the training pilots in frequency and time dimensions respectively. In contrast to other methods, the proposed scheme has moderate complexity and allows flexible subcarrier assignment schemes for the OFDMA system. The analysis and simulation results show that the proposed method performs well in the uplink channels. The initial synchronization tasks in the downlink including the cell identification, and the timing and frequency synchronization are studied. Several typical synchronization methods are presented and compared with each other. It shows that the MMSE method achieves the best performance for the timing estimation. In order to reduce the plateau of the metrics, a time domain smooth window is used with which a single peak is observed for all metrics. After the timing and frequency synchronization, a frequency domain correlation algorithm is applied for the cell identification. The overall performance of the initial synchronization was evaluated under multiple access interference, which gives the reference preamble power for designing the system. Finally, channel estimation algorithms are investigated. MMSE interpolation, FFT-based interpolation and polynomial interpolation methods are presented and compared with each other. Simulation results show that MMSE interpolation is superior to other methods in terms of MSE performance. However considering the trade-off between performance and complexity, the polynomial interpolation is a good approach. The effect of residual synchronization errors on channel estimation performance is studied. The modified channel estimation method to compensate residual synchronization errors is proposed. It shows that our compensation methods considerably improve the performance of channel estimators in imperfect synchronization conditions.

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Hamarneh, Ramez. "Analytical Calibration Scheme Suitable for Modern Mobile Communication Systems." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-289644.

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Modern systems utilize multiple transceiver modules to enhance capacity by directing the energy of the basestation only at the desired directions using beamforming algorithms. To accurately control the beam patterns, the phase and amplitude at each antenna port must be manipulated to follow the desired beam weight response. In a real system electrical, mechanical, and thermal variations for each antenna port path introduces different amplitude and phase errors. To ensure the desired performance, calibration at the antenna ports must be performed. The distinct transmit and receive frequencies in FDD systems poses the limitation that the sensing of the system must happen at the port of the antenna with a directional coupler or alter the antenna with a probe, but a traditional mutual coupling calibration can be used . In this work, a mutual coupling calibration scheme exploiting edge elements on the periphery of the array in tandem with array symmetry suitable to overcome this limit is proposed. To enable the scheme, the edge element frame must be able to receive and transmit in both frequency bands to facilitate transmitter or receiver calibration. This is achieved by connecting the edge element to a transmit/receive module that is in turn connected to a single-pole-dual-through switch and a bandpass filter that covers both uplink and downlink frequency bands. The single-pole-dual-through switch has a single input/output which is connected to and can be switched between two outputs/inputs. The array symmetry enables a larger array size when utilising a particular mutual coupling order. This is achieved by dividing a rectangular array across its breadth symmetry line and assigning the antenna element columns to their nearest edge element column. The division across the line of symmetry enables a particular mutual coupling order to be used in calibrating the column that corresponds to it in each half, thus, enabling a larger array. The full array calibration is then achieved by utilising a row of edge elements to calibrate the columns. The collective use of array symmetry and an edge element frame enables the analytical calibration methodology derived in this work. The scheme was then further verified numerically by using 2nd order mutual coupling to calibrate a 6 X 6 patch antenna array.
Moderna radiosystem använder multipla sändar- och mottagarmoduler för att förbättra datakapaciteten genom att rikta energin från basstationen enbart i de önskade riktningarna med hjälp av strålformningsalgoritmer. För att uppnå önskad strålbild måste fasen och amplituden av varje enskild antennport kontrolleras med hög noggrannhet. I praktiken introduceras fas- och amplitudfel av elektroniska, mekaniska och termiska variationer. För att försäkra sig om att den önskade strålbilden uppnås måste varje enskild antennport kalibreras. På grund av de åtskilda sändar- och mottagarfrekvenserna i FDD-system måste avkänningen ske på antennporten med en riktningskoppling eller genom att ändra antennporten, men traditionell kalibrering med hjälp av ömsesidig koppling kan användas. I det här arbetet föreslår vi en kalibreringsmetod som utnyttjar ömsesidig koppling hos kantelementen i gruppantennen, samt symmetrin i gruppantennen, för att överkomma denna begränsning. För att kunna kalibrera sändare och mottagare måste kantelementen i gruppantennen kunna sända och ta emot i båda frekvensbanden. Detta uppnås genom att koppla kantelementen till en sändar-/mottagarmodul som i sin tur är kopplad till en enpolig- dubbellomkopplare och ett bandpassfilter. Den enpoliga-dubbellomkopplaren har en in-/utgång som är kopplad till och kan omkopplas mellan två ut-/ingångar. Detta uppnås genom att dela upp gruppanntennen på bredden och tilldela antennelementskolumnerna till sitt närmaste kantelement. Uppdelning längs symmetrilinjen gör så att en viss ömsesidig kopplingsordning kan användas för kalibreringen av kolumnerna, vilket leder till att större gruppantenner kan kalibreras. Hela gruppantennen kalibreras sedan med hjälp av en rad av kantelement. Användandet av symmetri i gruppantennen och kantelementen möjliggör den analytiska kalibreringsmetod som tagits fram i detta arbete. Metoden verifierades med numeriska beräkningar genom att använda andra ordningens ömsesidiga koppling för att kalibrera en 6x6 gruppantenn bestående av patchelement.

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46

Xu, Benshuai. "Time varying channel models for 5G mobile communication systems." Thesis, University of Greenwich, 2014. http://gala.gre.ac.uk/13270/.

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Researchers all over the world are looking for ways of continuing the evolution of mobile communication technology to its fifth generation (5G). Providing high data rate information transfer to highly mobile users over time varying communication channels remains a shared obstacle. In this thesis, we contribute to these global efforts by providing further fundamental understanding of time varying channels in 5G mobile communication systems and overcome the obstacle. First, we reopen the door of research in the field of time varying communication channels. The door has almost been closed before by a well-accepted conclusion related to the types of channels. It was ‘proven’ that mutual information rate of the uniformly symmetric variable noise finite state Markov channel (USVNFSMC) was maximized by input signals of maximum information entropy. The result means time varying channels and time invariable channels are identical, regarding information rate maximization over input signal probability distribution. We provide evidence that assumptions for the results are not valid for time varying channels and replace them with more practical ones. We confirm, via input signals of non-uniform independent distribution and first order Markov chain, that the mutual information rate of the USVN-FSMC is maximized by input signals with information redundancy. Second, we provide a solution which dramatically reduces the waste of communication resources in estimating channel state information of time varying mobile communication channels. The orthodox method in dealing with time varying channels is that, the channel is “cut” to pieces in time domain to look like a sequence of time invariable channels for the purpose of state estimation. By doing this the capacity loss is staggering for n-times higher carrier frequency channels and n-dimensional multiple input and multiple output channels, eliminating almost entirely the capacity gain of these two most promising capacity-increasing techniques for 5G. We define the simplest finite state Markov model for time varying channels to explain the essential difference between information processing of time varying channels and time invariable channels. We prove that the full information capacity of the model can be achieved by the differential type encoding/decoding scheme without employing any conventional channel state estimator.

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Cheng, Xiang. "MIMO channel modelling and simulation for cellular and mobile-to-mobile communication systems." Thesis, Heriot-Watt University, 2009. http://hdl.handle.net/10399/2264.

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Recently, mobile-to-mobile (M2M) communications have received much attention due to several emerging applications, such as wireless mobile ad hoc networks, relay-based cellular networks, and dedicated short range communications (DSRC) for intelligent transportation systems (e.g., IEEE 802.11p standard). Different from conventional fixed-to-mobile (F2M) cellular systems, in M2M systems both the transmitter (Tx) and receiver (Rx) are in motion and often equipped with low elevation antennas. Multiple-input-multiple-output (MIMO) technologies, employing multiple antennas at both the Tx and Rx, have widely been adopted for the third generation (3G) and beyond-3G (B3G) F2M cellular systems due to their potential benefits of improving coverage, link reliability, and overall system capacity. More recently, MIMO has been receiving more and more attention for M2M systems as well. Reliable knowledge of the propagation channel obtained from channel measurements and corresponding channel models serve as the enabling foundation for the design and analysis of MIMO F2M and M2M systems. Furthermore, the development of accurate MIMO F2M and M2M channel simulation models plays a major role in the practical simulation and performance evaluation of these systems. These form the primary motivation behind our research on MIMO channel modelling and simulation for F2M cellular and M2M communication systems. In this thesis, we first propose a new wideband theoretical multiple-ring based MIMO regular-shaped geometry-based stochastic model (RS-GBSM) for non-isotropic scattering F2M macro-cell scenarios and then derive a generic space-time-frequency (STF) correlation function (CF). The proposed theoretical reference wideband model can be reduced to a narrowband one-ring model, a new closed-form STF CF of which is derived as well. Narrowband and wideband sum-of-sinusoids (SoS) simulation models are then developed, demonstrating a good agreement with the corresponding reference models in terms of correlation functions. Secondly, based on a well-known narrowband two-ring single-input single-output (SISO) M2M channel reference model, we propose new deterministic and stochastic SoS simulation models for non-isotropic scattering environments. The proposed deterministic simulator is the first SISO M2M deterministic simulator with good performance, while the proposed stochastic simulator outperforms the existing one in terms of fitting the desired statistical properties of the corresponding reference model. Thirdly, a new adaptive narrowband MIMO M2M RS-GBSM is proposed for nonisotropic scattering environments. To the best of our knowledge, the proposed M2M model is the first RS-GBSM that has the ability to study the impact of the vehicular traffic density on channel statistics. From the proposed theoretical reference model, we comprehensively investigate some important M2M channel statistics including the STF CF, space-Doppler-frequency power spectral density, envelope level crossing rate, and average fade duration. A close agreement between some channel statistics obtained from the proposed reference model and measurement data is observed, confirming the utility of our model. Finally, we extend the above narrowband model to a new wideband MIMO M2M RSGBSM with respect to the frequency-selectivity. The proposed wideband reference model is validated by observing a good match between some statistical properties of the theoretical model and available measurement data. From the wideband reference model, we further design new wideband deterministic and stochastic SoS simulation models. The proposed wideband simulators can be easily reduced to narrowband ones. The utilities of the newly derived narrowband and wideband simulation models are validated by comparing their statistical properties with those of the corresponding reference models. The proposed channel reference models and simulators are expected to be useful for the design, testing, and performance evaluation of future MIMO cellular and M2M communication systems.

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48

Dong, Ying. "Providing security services for mobile ad hoc networks." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B3955711X.

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Thavarajah, Arunasala Iyer. "A study of fixed channel assignment algorithms for cellular mobile radio systems." Thesis, Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21241144.

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Neo, Soo Sim Daniel. "Free space optics communication for mobile military platforms." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Dec%5FNeo.pdf.

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Dissertations / Theses on the topic 'Mobile communication systems Forecasting'

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