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The Global ETD Search service is a free service for researchers
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Showing 61 to 68 of 68 (0.031 seconds)Spelling suggestions: "subject:"amobile network"" "subject:"0mobile network""
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Modélisation et simulation des réseaux sans fil hétérogènes et non-stationnaires : Application aux topologies de petites cellules / Modeling and simulation of heterogeneous and non-stationary wireless networks : Application to small cells topologiesMaviel, Laurent 27 May 2013 (has links)
Les nouveaux services de télécommunication accessibles en mobilité entraînent une demande croissante de débit et amènent aux limites de capacités des réseaux actuels. Pour répondre à cette demande, les opérateurs cellulaires déploient de nouvelles technologies et densifient leurs réseaux en ajoutant des petites cellules, où les stations de base sont plus proches des utilisateurs. Compte tenu de la visibilité directe et de la faible hauteur des antennes, le canal de propagation des petites cellules est différent de celui des macro-cellules et les modèles stochastiques de canal existants ne sont plus adaptés. C’est dans ce contexte que se situe cette thèse, qui explore les problématiques de dynamique dans le canal de propagation et dans l’utilisation des ressources radio. Nous proposons dans une première partie de caractériser les dynamiques dans le canal de propagation de petite cellule en milieu extérieur. Cette caractérisation se base sur des prédictions déterministes, où une partie de l’environnement est généré de manière aléatoire afin de procéder à des études statistiques. Pour cela, nous mettons en place une plateforme de simulation, capable de générer des objets statiques, de les déplacer et de les prendre en compte dans des outils de prédiction de propagation adaptés aux petites cellules. Une phase de mesures de l’impact du trafic de véhicules sur la puissance du signal permet de valider les outils de propagation développés dans la plateforme. L’objectif de la deuxième partie de la thèse est d’évaluer l’impact de ces nouvelles topologies sur les performances des réseaux hétérogènes. Nous présentons un modèle hybride de propagation qui prend en compte les variations de signal dues au trafic de véhicules en combinant les approches déterministes et statistiques, pour avoir les avantages de résultats précis et d’un temps de calcul rapide. Ce modèle hybride est utilisé par la suite dans un processus de simulation de réseau cellulaire 3G LTE au niveau système, où nous évaluons l’impact du trafic de véhicules sur le débit maximal, la consommation d’énergie et le respect de la qualité de service. / New services available with modern mobile telecommunication networks lead to a growing demand for better bit rates up to reach the capacity limits of current networks. To face this demand, cellular network operators deploy new technologies and densify their radio access by adding small cells, where the distance between the mobile users and the base stations is decreased. Given the Line of Sight conditions and the low height of base station antennas, the small-cell propagation channel is different from the classical macro-cellular channel and existing stochastic channel models are not suited anymore. In this context, this Ph.D. work proposes to explore challenges on the dynamics of the channel and of radio resource usage. In a first part, we propose to characterize the dynamics of the propagation channel in small-cell outdoor environments. This characterization is based on deterministic predictions, where part of the environment is randomly generated in order to proceed to statistical analysis. We describe a simulation framework able to generate static objects, to move them and to take them into account in propagation prediction tools targeted for small-cell environments. Measurements of the impact of vehicular traffic on received power enable the validation of propagation tools developed in the framework. In the second part of this work, we propose to evaluate the impact of those new topologies on the performance of heterogeneous networks. We present a hybrid propagation model taking into account signal variations due to vehicular traffic by combining deterministic and statistic approaches in order to benefit from both advantages: accurate results and quick simulations. This hybrid model is finally used in a cellular 3G LTE network simulation process where we evaluate the impact of vehicular traffic on maximal throughputs, energy consumption and quality of service.
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Heterogeneous Networks: from integration to mobilityQachri, Naïm 16 September 2015 (has links)
Français:La notion de réseaux hétérogènes correspond à l’intégration de plusieurs technologies de transmission de données sans-fil dans le but d’accroitre la qualité de service des communications dans les réseaux mobiles.Historiquement, les mécanismes de sécurité des réseaux mobiles et sans-fil ont été largement focalisés sur la protection d’équipement utilisateur au niveau du dernier saut de communication et sur base d’une connectivité simple et unique. Cette connectivité, réduite à sa plus simple expression, a restraint le développement des protocoles de sécurité à des protocoles bi-parties, qui couvrent l’authentification des équipements utilisateurs et le chiffrement sur des communicationsLes mécanismes de sécurité et de cryptographie ne sont donc pas suffisants pour protéger correctement et efficacement des connections parallèles ou leur mobilité au sein de réseaux hétérogènes. Le but de cette thèse de doctorat, à travers quatre contributions personnelles, est d’apporter de nouveaux mécanismes et protocoles de sécurité afin de protéger au mieux les réseaux hétérogènes:• La première contribution se focalise sur le développement d’une nouvelle primitive cryptographique pour la protection des transmissions sans-fil. La propriété principale de celle-ci est de protéger les trames en cas de capture. Cette primitive introduit, notamment, la notion de force brute probabiliste (ce qui veut dire qu’un attaquant ne peut pas choisir parmi différentes clés équiprobables laquelle est effectivement utilisée).• La seconde contribution propose un nouveau protocole pour gérer d’une manière sure et efficace la mobilité des équipements utilisateurs entre différentes technologies au sein de réseaux hétérogènes.• La troisième contribution couvre la gestion des clés maîtres des utilisateurs, embarqués au sein des cartes SIM, utilisées au sein des réseaux d’opérateurs mobiles. Nos protocoles et mécanismes automa- tisent des changements réguliers et sûrs de la clé maître, et ajoutent de la diversité dans la gestion des clés de sessions pour minimiser l’impact en cas de révélation de ces dernières (par le biais d’un vol de base de donnée, par exemple)• La quatrième contribution introduit un nouveau paradigme de connectivité pour les réseaux mo- biles basé sur des communications 1−à−n. Le paradigme redéfinit les frontières de sécurité et place l’équipement utilisateur au centre d’un groupe authentifié mobile. Par conséquent, le changement de paradigme mène à la création de nouveaux protocoles pour l’authentification, la gestion de la mo- bilité et la négociation protégées de clés afin de fournir une protection de bout en bout entre deux équipements utilisateurs ou plus. / English:Heterogeneous Networks (HetNets) is the integration of multiple wireless technologies to increase the quality of service of the communications in mobile networks. This evolution is the next generation of Public Land Mobile Networks (PLMNs).Mobile and wireless network security mechanisms have largely focused on the protection of the User Equipment (UE) within the last mile (the last hop of the communication in the chain of connected devices) and on single connections. The single connectivity has reduced the development of the security to two party protocols, and they cover the authentication of the UE to the mobile network and the encryption on a single channel based on homogeneous communications through a unique technology.The current security and cryptographic mechanisms are not sufficient to protect correctly, and efficiently, parallel connections or their mobility in HetNets. The purpose of the PhD Thesis is to bring new security protocols and mechanisms to protect HetNets.The contributions, that are brought by the thesis, follow the evolution of HetNets through 4 contributions by starting from the wireless transmissions to the largest frame of HetNets architecture:• The first contribution focuses on the development of an new cryptographic primitives for wireless transmissions. The main property is to protect the frame from eavesdropping. The primitive introduces the notion of probabilistic brute force (meaning that an attacker cannot decide among different keys which the used one).• The second contribution proposes a new protocol to manage efficiently and securely the mobility of the UEs between different technologies inside HetNets.• The third contribution covers the management of the master secrets, embedded within the Universal Subscriber Identity Module (USIM), in large PLMNs. Our mechanisms and protocols automate regular and secure changes of the master secret, and they add diversity in the management of session keys to minimize the impact of key leakages (in case of credential database theft, for instance).• The fourth contribution introduces a new connectivity paradigm for mobile networks based on one-to- many communications. The paradigm redesigns the security borders and puts the UE in the center of a mobile authenticated group. Therefore, the paradigm shift leads to new security protocols for authentication, mobility management, and secure negotiation to provide end-to-end encryption between two or more UEs. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
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Customer service on the Czech mobile telecommunication market. Comparative Analysis / Zákaznické služby na českém mobilním telekomunikačním trhu. Komparativní analýzaHanzlík, Radek January 2013 (has links)
The main goal of this thesis is to compare the quality of customer service between the Mobile Network Operators (MNOs) and Mobile Virtual Network Operators (MVNOs) on the Czech mobile telecommunication market. The mystery shopping method is used as the source of data for the comparative analysis.
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Univerzální testovací zařízení pro ověření komunikačních parametrů technologie Narrowband IoT / Universal Tester of Radio Conditions for Narrowband IoT Communication TechnologyMožný, Radek January 2019 (has links)
Technology Narrowband IoT is a representative LPWA (Low Power Wide Area) tech-nology that due to its promising features aims for demands of the Internet of Thingsapplications for autonomous data sending from sensors in areas of poor mobile coverage.For such applications, it is beneficial to firstly map properties of communication technol-ogy in areas of intended use and evaluate whether or not is this technology applicable.This Master thesis deals with the design of the hand-held measuring device for evaluationof Narrowband IoT properties. The output of this thesis is firstly comparison of LPWAtechnologies secondly, design of the mentioned device and verification of its functional-ity. And in last part description of measurement of transmission delay for delay-tolerantapplications. Transmission delay is a critical parameter for delay-tolerant applications.Such an application can be, for example, smart electrometers for which there is definedmaximal allowed transmission delay of 10 seconds and therefore it is desirable to evalu-ate whether or not is the deployment of the communication technology Narrowband IoTsuitable in the intended area for delay-tolerant or even for delay-intolerant applications.
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Belief-aided Robust Control for Remote Electrical Tilt OptimizationJönsson, Jack January 2021 (has links)
Remote Electrical Tilt (RET) is a method for configuring antenna downtilt in base stations to optimize mobile network performance. Reinforcement Learning (RL) is an approach to automating the process by letting an agent learn an optimal control strategy and adapt to the dynamic environment. Applying RL in real world comes with challenges, for the RET problem there are performance requirements and partial observability of the system through exogenous factors inducing noise in observations. This thesis proposes a solution method through modeling the problem by a Partially Observable Markov Decision Process (POMDP). The set of hidden states are modeled as a high- level representation of situations requiring one of the possible actions uptilt, downtilt, no change. From this model, a Bayesian Neural Network (BNN) is trained to predict an observation model, relating observed Key Performance Indicators (KPIs) to the hidden states. The observation model is used for estimating belief state probabilities of each hidden state, from which decision of control action is made through a restrictive threshold policy. Experiments comparing the method to a baseline Deep Q- network (DQN) agent shows the method able to reach the same average performance increase as the baseline while outperforming the baseline in two metrics important for robust and safe control behaviour, the worst- case minimum reward increase and the average reward increase per number of tilt actions. / Fjärrstyrning av Elektrisk Lutning (FEL) är en metod för att reglera lutningen av antenner i basstationer för att optimera presentandan i ett mobilnätverk. Förstärkande Inlärning (FI) används som metod för att automatisera processen genom att låta en agent lära sig en optimal strategi för reglering och anpassa sig till den dynamiska miljön. Att tillämpa FI i ett verkligt scenario innebär utmaningar, för FEL specifikt finns det krav på en viss nivå av prestanda samt endast en delvis observerbarhet av systemet på grund av externa faktorer som orsakar brus i observationerna. I detta arbete föreslås en metod för att hantera detta genom att modellera problemet som en Delvis Observerbar Markovprocess (DOM). De dolda tillstånden modelleras för att representera situationer där var och en av de möjliga aktionerna behövs, det vill säga att luta antennen upp, ner eller inte ändra på lutningen. Utifrån denna modellering så tränas ett Bayesiskt Neuralt Nätverk (BNN) för att estimera en observationsmodel som kopplar observerade nyckeltal till de dolda tillstånden. Denna observationsmodel används för att estimera sannolikheten att vardera dolt tillstånd är det rätta. Utifrån dessa sannolikheter så görs valet av aktion genom ett tröskelvärde på sannolikheterna. Genom experiment som jämför metoden med en standardimplementering av en agent baserad på ett Djupt Qnätverk (DQN) visas att metoden har samma prestation när det kommer till en medelnivå på prestandaökning i nätverket. Metoden överträffar dock standardmetoden i två andra mätvärden som är viktiga ur aspekten säker och robust reglering, minimumvärdet på prestandaökningen samt medelökningen av prestandan per antal up- och nerlutningar som används.
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[en] DEVELOPMENT OF A SIMULATION TOOL FOR CELLULAR NETWORK PLANNING AND PERFORMANCE EVALUATION BASED ON THE SIGNALING LOAD / [pt] DESENVOLVIMENTO DE UMA FERRAMENTA DESIMULAÇÃO PARA PLANEJAMENTO E ANÁLISE DO DESEMPENHO DE REDES CELULARES A PARTIR DA CARGA DE SINALIZAÇÃO GERADARODRIGO CESAR D ALBRIEUX DE CARVALHO 14 June 2002 (has links)
[pt] Com o advento dos sistemas celulares de segunda e terceira
gerações é esperado que as operadoras se vejam obrigadas a
enfrentar um aumento dramático na carga de sinalização
que trafega sobre a parte fixa da rede móvel. Apesar disso,
são raros os provedores de serviços de comunicações móveis
que possuem atualmente a capacidade de prever com
relativa precisão o montante desse aumento. Este trabalho
apresenta as etapas do desenvolvimento de uma ferramenta de
simulação para análise de desempenho de redes de
comunicação móvel celular com base na carga de sinalização
gerada pelos procedimentos que a mantém em operação. A
plataforma de simulação inclui um modelo de mobilidade e
teletráfego para caracterizar o processo de geração dos
cenários típicos de uma rede móvel celular e um modelo de
retardos para representação da rede de sinalização. Ao
final do estudo,são apresentados exemplos de aplicação da
ferramenta na obtenção de resultados sobre gerência de
status, gerência de localização, avaliação da carga de
sinalização,dimensionamento da rede de sinalização e
análise de desempenho para diferentes configurações de rede. / [en] The advent of second and third generation cellular systems
make cellular operators face dramatic increase in the
signaling traffic over the fixed part of the mobile
network. In spite of this, rare mobile communications
service providers are able to forecast the above mention
increase and quantify it with reasonable precision. This
work describes the development process of a simulation tool
for performance analysis of cellular mobile network based
on the signaling load generated by the procedures that
keeps it working. The simulation platform inlcudes a
mobility and teletraffic model to describe the generation
process of cellular mobile networks tipical scenarios and a
delay model to represent the signaling network. At the end,
examples showing the application of the simulation tool to
obtain results about status and location management,
signaling load evaluation, signaling network planning and
performance analysis for different network configurations
are presented.
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Legal and regulatory aspects of mobile financial servicesPerlman, Leon Joseph 11 1900 (has links)
The thesis deals with the emergence of bank and non-bank entities that provide a range of unique
transaction-based payment services broadly called Mobile Financial Services (MFS) to unbanked,
underserved and underbanked persons via mobile phones.
Models of MFS from Mobile Network Operators (MNOs), banks, combinations of MNOs and banks, and
independent Mobile Financial Services Providers are covered. Provision by non-banks of ‘bank-type’
services via mobile phones has been termed ‘transformational banking’ versus the ‘additive banking’
services from banks. All involve the concept of ‘branchless banking’ whereby ‘cash-in/cash out’ services
are provided through ‘agents.’
Funds for MFS payments may available through a Stored Value Product (SVP), particularly through a
Stored Value Account SVP variant offered by MNOs where value is stored as a redeemable fiat- or mobile
‘airtime’-based Store of Value.
The competitive, legal, technical and regulatory nature of non-bank versus bank MFS models is discussed,
in particular the impact of banking, payments, money laundering, telecommunications, e-commerce and
consumer protection laws. Whether funding mechanisms for SVPs may amount to deposit-taking such that
entities could be engaged in the ‘business of banking’ is discussed. The continued use of ‘deposit’ as the
traditional trigger for the ‘business of banking’ is investigated, alongside whether transaction and paymentcentric
MFS rises to the ‘business of banking.’
An extensive evaluation of ‘money’ based on the Orthodox and Claim School economic theories is
undertaken in relation to SVPs used in MFS, their legal associations and import, and whether they may be
deemed ‘money’ in law.
Consumer protection for MFS and payments generally through current statute, contract, and payment law
and common law condictiones are found to be wanting. Possible regulatory arbitrage in relation to MFS in
South African law is discussed.
The legal and regulatory regimes in the European Union, Kenya and the United States of America are
compared with South Africa. The need for a coordinated payments-specific law that has consumer
protections, enables proportional risk-based licensing of new non-bank providers of MFS, and allows for a
regulator for retail payments is recommended. The use of trust companies and trust accounts is
recommended for protection of user funds.
| vi / Public, Constitutional and International Law / LLD
|
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Legal and regulatory aspects of mobile financial servicesPerlman, Leon Joseph 11 1900 (has links)
The thesis deals with the emergence of bank and non-bank entities that provide a range of unique
transaction-based payment services broadly called Mobile Financial Services (MFS) to unbanked,
underserved and underbanked persons via mobile phones.
Models of MFS from Mobile Network Operators (MNOs), banks, combinations of MNOs and banks, and
independent Mobile Financial Services Providers are covered. Provision by non-banks of ‘bank-type’
services via mobile phones has been termed ‘transformational banking’ versus the ‘additive banking’
services from banks. All involve the concept of ‘branchless banking’ whereby ‘cash-in/cash out’ services
are provided through ‘agents.’
Funds for MFS payments may available through a Stored Value Product (SVP), particularly through a
Stored Value Account SVP variant offered by MNOs where value is stored as a redeemable fiat- or mobile
‘airtime’-based Store of Value.
The competitive, legal, technical and regulatory nature of non-bank versus bank MFS models is discussed,
in particular the impact of banking, payments, money laundering, telecommunications, e-commerce and
consumer protection laws. Whether funding mechanisms for SVPs may amount to deposit-taking such that
entities could be engaged in the ‘business of banking’ is discussed. The continued use of ‘deposit’ as the
traditional trigger for the ‘business of banking’ is investigated, alongside whether transaction and paymentcentric
MFS rises to the ‘business of banking.’
An extensive evaluation of ‘money’ based on the Orthodox and Claim School economic theories is
undertaken in relation to SVPs used in MFS, their legal associations and import, and whether they may be
deemed ‘money’ in law.
Consumer protection for MFS and payments generally through current statute, contract, and payment law
and common law condictiones are found to be wanting. Possible regulatory arbitrage in relation to MFS in
South African law is discussed.
The legal and regulatory regimes in the European Union, Kenya and the United States of America are
compared with South Africa. The need for a coordinated payments-specific law that has consumer
protections, enables proportional risk-based licensing of new non-bank providers of MFS, and allows for a
regulator for retail payments is recommended. The use of trust companies and trust accounts is
recommended for protection of user funds.
| vi / Public, Constitutional and International Law / LL. D.
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