Author: Khaled Dridi
Publisher:
ISBN:
Category :
Languages : fr
Pages : 0
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Book Description
Cette thèse a pour objectif de proposer de nouvelles approches d'ordonnancement, de coopération et de gestion de la mobilité dans les réseaux sans fil de type IEEE 802.11. Le maintien de la qualité de service (QoS), au niveau MAC, représente la caractéristique fondamentale de ces approches. L'analyse des mécanismes existants nous a conduits à retenir le protocole EDCF, supportant la QoS, comme une base de travail pour l'ensemble de nos propositions. Dans le but de pallier certaines faiblesses du standard 802.11, une nouvelle architecture à base de multi-ordonnanceurs HCF-T, est proposée. Les performances obtenues sont exprimées en termes de gestion du trafic, de maintien du débit, d'élimination de collisions et de réduction de la charge du réseau. Ensuite, un schéma coopératif est présenté et analysé. Il comporte une étude de deux protocoles de relayage AAF et DAF ainsi qu'une évaluation d'un ensemble de techniques de combinaison au niveau du récepteur. Concernant la problématique de la mobilité, nous avons retenu et analysé un scénario prenant en considération les différentes situations rencontrées dans un modèle réel. Un algorithme de résolution multi-couvertures est proposé afin de traiter l'accès dans les zones de recouvrement. Cette étude a mené à distinguer trois régimes de mobilité : faible, moyen et fort. Les performances sont évaluées en fonction des métriques MAC et pour chaque mode de mobilité, un schéma de synthèse est établi.
Author: Xavier Begaud
Publisher: John Wiley & Sons
ISBN: 1118586573
Category : Technology & Engineering
Languages : en
Pages : 217
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Book Description
Ultra Wide Band Technology (UWB) has reached a level of maturity that allows us to offer wireless links with either high or low data rates. These wireless links are frequently associated with a location capability for which ultimate accuracy varies with the inverse of the frequency bandwidth. Using time or frequency domain waveforms, they are currently the subject of international standards facilitating their commercial implementation. Drawing up a complete state of the art, Ultra Wide Band Antennas is aimed at students, engineers and researchers and presents a summary of internationally recognized studies.
Author: Alain Sibille
Publisher: Academic Press
ISBN: 0123821959
Category : Technology & Engineering
Languages : es
Pages : 385
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Book Description
Foreword from Arogyaswami Paulraj, Professor (Emeritus), Stanford University (USA) - The first book to show how MIMO principles can be implemented in today's mobile broadband networks and components - Explains and solves some of the practical difficulties that arise in designing and implementing MIMO systems - Both theory and implementation sections are written in the context of the most recent standards: IEEE 802.11n (WiFi); IEEE 802.16 (WIMAX); 4G networks (3GPP/3GPP2, LTE)
Author: Paolo Prandoni
Publisher: Collection Savoir suisse
ISBN: 2940222207
Category : Signal processing
Languages : en
Pages : 392
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Book Description
With a novel, less classical approach to the subject, the authors have written a book with the conviction that signal processing should be taught to be fun. The treatment is therefore less focused on the mathematics and more on the conceptual aspects, the idea being to allow the readers to think about the subject at a higher conceptual level, thus building the foundations for more advanced topics. The book remains an engineering text, with the goal of helping students solve real-world problems. In this vein, the last chapter pulls together the individual topics as discussed throughout the book into an in-depth look at the development of an end-to-end communication system, namely, a modem for communicating digital information over an analog channel.
Author: Roberto Verdone
Publisher: Springer Science & Business Media
ISBN: 144712314X
Category : Computers
Languages : en
Pages : 696
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Book Description
Reporting the findings of COST 2100, a major European intergovernmental project, this volume offers system designers a good source of guidelines based on channel characterization and measurement-based modeling, as well as worthwhile ideas for future research.
Author: Eric Brousseau
Publisher: Cambridge University Press
ISBN: 1107013429
Category : Business & Economics
Languages : en
Pages : 463
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Book Description
An interdisciplinary survey of the issues surrounding the governance of the Internet.
Author: Neil Gershenfeld
Publisher: Cambridge University Press
ISBN: 9780521580441
Category : Computers
Languages : en
Pages : 390
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Book Description
The Physics of Information Technology explores the familiar devices that we use to collect, transform, transmit, and interact with electronic information. Many such devices operate surprisingly close to very many fundamental physical limits. Understanding how such devices work, and how they can (and cannot) be improved, requires deep insight into the character of physical law as well as engineering practice. The book starts with an introduction to units, forces, and the probabilistic foundations of noise and signalling, then progresses through the electromagnetics of wired and wireless communications, and the quantum mechanics of electronic, optical, and magnetic materials, to discussions of mechanisms for computation, storage, sensing, and display. This self-contained volume will help both physical scientists and computer scientists see beyond the conventional division between hardware and software to understand the implications of physical theory for information manipulation.
Author: Michel Le Bellac
Publisher: Cambridge University Press
ISBN: 1139457047
Category : Science
Languages : en
Pages : 179
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Book Description
Quantum information and computation is a rapidly expanding and cross-disciplinary subject. This book, first published in 2006, gives a self-contained introduction to the field for physicists, mathematicians and computer scientists who want to know more about this exciting subject. After a step-by-step introduction to the quantum bit (qubit) and its main properties, the author presents the necessary background in quantum mechanics. The core of the subject, quantum computation, is illustrated by a detailed treatment of three quantum algorithms: Deutsch, Grover and Shor. The final chapters are devoted to the physical implementation of quantum computers, including the most recent aspects, such as superconducting qubits and quantum dots, and to a short account of quantum information. Written at a level suitable for undergraduates in physical sciences, no previous knowledge of quantum mechanics is assumed, and only elementary notions of physics are required. The book includes many short exercises, with solutions available to instructors through
[email protected].
Author: Francine Krief
Publisher: John Wiley & Sons
ISBN: 1118580893
Category : Technology & Engineering
Languages : en
Pages : 235
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Book Description
This book focuses on green networking, which is an important topic for the scientific community composed of engineers, academics, researchers and industrialists working in the networking field. Reducing the environmental impact of the communications infrastructure has become essential with the ever increasing cost of energy and the need for reducing global CO2 emissions to protect our environment. Recent advances and future directions in green networking are presented in this book, including energy efficient networks (wired networks, wireless networks, mobile networks), adaptive networks (cognitive radio networks, green autonomic networking), green terminals, and industrial research into green networking (smart city, etc.).
Author: Bixio Rimoldi
Publisher: Cambridge University Press
ISBN: 1107116457
Category : Computers
Languages : en
Pages : 313
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Book Description
A comprehensive text that takes a unique top-down approach to teaching the fundamentals of digital communication for a one-semester course.
