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Contribution A Loptimisation Des Performances Des Recepteurs Pour Les Futures Generations De Communications Mobiles
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Book Synopsis Contribution à l'optimisation des performances des récepteurs pour les futures générations de communications mobiles by : Chakib Belkhiri
Download or read book Contribution à l'optimisation des performances des récepteurs pour les futures générations de communications mobiles written by Chakib Belkhiri and published by . This book was released on 2005 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'accès à plusieurs services à partir d'un seul terminal mobile fait de la conversion homodyne l'architecture favorite pour les futurs systèmes de communication. Cependant, cette structure est très sensible aux nonlinéarités. Par conséquent, une linéarité élevée, une bonne isolation, et une forte réjection du mode commun, sont recommandées au niveau de chaque bloc RF, et particulièrement des mélangeurs. En outre, ces systèmes doivent couvrir des plages de fréquences assez larges pour permettre l'accès aux divers services proposés aux utilisateurs. De leur coté les VCOs doivent avoir des plages d'excursion importantes pour éviter la redondance des oscillateurs et minimiser ainsi la consommation. C'est donc l'optimisation des performances des mélangeurs et des VCOs qui est présentée dans ce mémoire. La combinaison des deux concepts classiques du mélange a aboutit à des topologies du type amplificateurs à contre réaction variable, permettant d'obtenir un mélange linéaire avec un gain de conversion important. Plusieurs circuits mélangeurs conçus en CMOS et BiCMOS montrent l'intérêt de cette topologie. D'autre part, l'élargissement de la bande d'excursion des VCOs par l'utilisation de la technique de compensation de la réactance et des oscillateurs push push a été démontré.
Book Synopsis Contribution à l'optimisation des performances des amplificateurs de puissance utilisés dans les terminaux portables pour les communications mobiles de futures générations by : Sylvain Reed
Download or read book Contribution à l'optimisation des performances des amplificateurs de puissance utilisés dans les terminaux portables pour les communications mobiles de futures générations written by Sylvain Reed and published by . This book was released on 2005 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ce mémoire présente une nouvelle technique d'optimisation de performances des amplificateurs de puissance dédiés aux terminaux de radiocommunication mobiles de troisième génération. Le fonctionnement de ces composants doit être optimisé sur une grande dynamique de puissance de sortie. C'est pourquoi une nouvelle technique d'optimisation est développée : "amplificateur à polarisation dynamique adaptative". Elle consiste à injecter, au niveau du circuit de polarisation de base des transistors HBT constituant l'amplificateur de puissance, un signal qui est fonction de l'enveloppe du signal à amplifier et de la puissance de sortie. Ce signal peut être calculé dans la partie numérique du terminal mobile. Un nouveau banc de caractérisation a été conçu pour déterminer les signaux de polarisation optimaux. Un prototype a été réalisé en technologie hybride. Celui-ci permet de valider la technique développée. De plus, une conception monolithique a été développée pour démontrer son intégrabilité.
Book Synopsis Mobile Fading Channels by : Matthias Pätzold
Download or read book Mobile Fading Channels written by Matthias Pätzold and published by Wiley-Blackwell. This book was released on 2002-04 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mobile channel fading is a loss in transmission intensity caused by changes in the transmission medium. By dealing with the modelling, analysis and simulation of mobile fading channels this text provides a fundamental understanding of many issues in the area of mobile fading channel modelling.; The main topics addressed in the volume are: fundamentals of stochastic and deterministic channel models and modelling and simulation of frequency-nonselective and frequency-selective fading channels. The guide also features methods for the design and realization of efficient channel simulators and fast channel simulators and MATLAB-programs for the evaluation and simulation of mobile fading channels.
Download or read book ICREEC 2019 written by Ahmed Belasri and published by Springer Nature. This book was released on 2020-06-10 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights peer reviewed articles from the 1st International Conference on Renewable Energy and Energy Conversion, ICREEC 2019, held at Oran in Algeria. It presents recent advances, brings together researchers and professionals in the area and presents a platform to exchange ideas and establish opportunities for a sustainable future. Topics covered in this proceedings, but not limited to, are photovoltaic systems, bioenergy, laser and plasma technology, fluid and flow for energy, software for energy and impact of energy on the environment.
Book Synopsis Disaster risk reduction in school curricula: case studies from thirty countries by :
Download or read book Disaster risk reduction in school curricula: case studies from thirty countries written by and published by UNESCO. This book was released on 2012 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ultra Wide Band Antennas by : Xavier Begaud
Download or read book Ultra Wide Band Antennas written by Xavier Begaud and published by John Wiley & Sons. This book was released on 2013-03-04 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 :Food and Agriculture Organization of the United Nations Publisher :Food & Agriculture Org. ISBN 13 :9789251045411 Total Pages :20 pages Book Rating :4.0/5 (454 download)
Book Synopsis What is the Code of Conduct for Responsible Fisheries? by : Food and Agriculture Organization of the United Nations
Download or read book What is the Code of Conduct for Responsible Fisheries? written by Food and Agriculture Organization of the United Nations and published by Food & Agriculture Org.. This book was released on 2001 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The actual Code of conduct is also available (1996) (ISBN 9251038341).
Book Synopsis Belief Functions: Theory and Applications by : Sébastien Destercke
Download or read book Belief Functions: Theory and Applications written by Sébastien Destercke and published by Springer. This book was released on 2018-09-07 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 5th International Conference on Belief Functions, BELIEF 2018, held in Compiègne, France, in September 2018.The 33 revised regular papers presented in this book were carefully selected and reviewed from 73 submissions. The papers were solicited on theoretical aspects (including for example statistical inference, mathematical foundations, continuous belief functions) as well as on applications in various areas including classification, statistics, data fusion, network analysis and intelligent vehicles.
Download or read book MIMO written by Alain Sibille and published by Academic Press. This book was released on 2010-12-03 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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)
Book Synopsis Torques and Attitude Sensing in Earth Satellites by : Siegfried Fred Singer
Download or read book Torques and Attitude Sensing in Earth Satellites written by Siegfried Fred Singer and published by . This book was released on 1964 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Pervasive Mobile and Ambient Wireless Communications by : Roberto Verdone
Download or read book Pervasive Mobile and Ambient Wireless Communications written by Roberto Verdone and published by Springer Science & Business Media. This book was released on 2012-01-02 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 :Food and Agriculture Organization of the United Nations Publisher :Food & Agriculture Org. ISBN 13 :9789251039717 Total Pages :52 pages Book Rating :4.0/5 (397 download)
Book Synopsis Aquaculture Development by : Food and Agriculture Organization of the United Nations
Download or read book Aquaculture Development written by Food and Agriculture Organization of the United Nations and published by Food & Agriculture Org.. This book was released on 1997 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides annotations to the Principles of Article 9 of the Code of Conduct for Responsible Fisheries. These annotations are meant to serve as general guidance, and should be taken as suggestions or observations intended to assist those interested in identifying their own criteria and options for actions, as well as partners for collaboration, in support of sustainable aquaculture development.
Book Synopsis Biotechnology and Sustainable Development by : Ismail Serageldin
Download or read book Biotechnology and Sustainable Development written by Ismail Serageldin and published by CABI. This book was released on 2003 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on the first scientific conference convened at the Library of Alexandria, 'Biotechnology and Sustainable Development: Voices of the South and North', which was held in Alexandria, Egypt, in March 2002, this book contains overviews of agriculture, health, ethics and the environment. It discusses how dramatic improvements in food security, health, and lifestyle could accrue to the poor people of developing countries through the applications of new technologies.
Download or read book Massive MIMO written by Hien Quoc Ngo and published by Linköping University Electronic Press. This book was released on 2015-01-16 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last ten years have seen a massive growth in the number of connected wireless devices. Billions of devices are connected and managed by wireless networks. At the same time, each device needs a high throughput to support applications such as voice, real-time video, movies, and games. Demands for wireless throughput and the number of wireless devices will always increase. In addition, there is a growing concern about energy consumption of wireless communication systems. Thus, future wireless systems have to satisfy three main requirements: i) having a high throughput; ii) simultaneously serving many users; and iii) having less energy consumption. Massive multiple-input multiple-output (MIMO) technology, where a base station (BS) equipped with very large number of antennas (collocated or distributed) serves many users in the same time-frequency resource, can meet the above requirements, and hence, it is a promising candidate technology for next generations of wireless systems. With massive antenna arrays at the BS, for most propagation environments, the channels become favorable, i.e., the channel vectors between the users and the BS are (nearly) pairwisely orthogonal, and hence, linear processing is nearly optimal. A huge throughput and energy efficiency can be achieved due to the multiplexing gain and the array gain. In particular, with a simple power control scheme, Massive MIMO can offer uniformly good service for all users. In this dissertation, we focus on the performance of Massive MIMO. The dissertation consists of two main parts: fundamentals and system designs of Massive MIMO. In the first part, we focus on fundamental limits of the system performance under practical constraints such as low complexity processing, limited length of each coherence interval, intercell interference, and finite-dimensional channels. We first study the potential for power savings of the Massive MIMO uplink with maximum-ratio combining (MRC), zero-forcing, and minimum mean-square error receivers, under perfect and imperfect channels. The energy and spectral efficiency tradeoff is investigated. Secondly, we consider a physical channel model where the angular domain is divided into a finite number of distinct directions. A lower bound on the capacity is derived, and the effect of pilot contamination in this finite-dimensional channel model is analyzed. Finally, some aspects of favorable propagation in Massive MIMO under Rayleigh fading and line-of-sight (LoS) channels are investigated. We show that both Rayleigh fading and LoS environments offer favorable propagation. In the second part, based on the fundamental analysis in the first part, we propose some system designs for Massive MIMO. The acquisition of channel state information (CSI) is very importantin Massive MIMO. Typically, the channels are estimated at the BS through uplink training. Owing to the limited length of the coherence interval, the system performance is limited by pilot contamination. To reduce the pilot contamination effect, we propose an eigenvalue-decomposition-based scheme to estimate the channel directly from the received data. The proposed scheme results in better performance compared with the conventional training schemes due to the reduced pilot contamination. Another important issue of CSI acquisition in Massive MIMO is how to acquire CSI at the users. To address this issue, we propose two channel estimation schemes at the users: i) a downlink "beamforming training" scheme, and ii) a method for blind estimation of the effective downlink channel gains. In both schemes, the channel estimation overhead is independent of the number of BS antennas. We also derive the optimal pilot and data powers as well as the training duration allocation to maximize the sum spectral efficiency of the Massive MIMO uplink with MRC receivers, for a given total energy budget spent in a coherence interval. Finally, applications of Massive MIMO in relay channels are proposed and analyzed. Specifically, we consider multipair relaying systems where many sources simultaneously communicate with many destinations in the same time-frequency resource with the help of a massive MIMO relay. A massive MIMO relay is equipped with many collocated or distributed antennas. We consider different duplexing modes (full-duplex and half-duplex) and different relaying protocols (amplify-and-forward, decode-and-forward, two-way relaying, and one-way relaying) at the relay. The potential benefits of massive MIMO technology in these relaying systems are explored in terms of spectral efficiency and power efficiency.
Book Synopsis The Patient Will See You Now by : Eric Topol
Download or read book The Patient Will See You Now written by Eric Topol and published by Basic Books. This book was released on 2016-10-25 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: The essential guide by one of America's leading doctors to how digital technology enables all of us to take charge of our health A trip to the doctor is almost a guarantee of misery. You'll make an appointment months in advance. You'll probably wait for several hours until you hear "the doctor will see you now"-but only for fifteen minutes! Then you'll wait even longer for lab tests, the results of which you'll likely never see, unless they indicate further (and more invasive) tests, most of which will probably prove unnecessary (much like physicals themselves). And your bill will be astronomical. In The Patient Will See You Now, Eric Topol, one of the nation's top physicians, shows why medicine does not have to be that way. Instead, you could use your smartphone to get rapid test results from one drop of blood, monitor your vital signs both day and night, and use an artificially intelligent algorithm to receive a diagnosis without having to see a doctor, all at a small fraction of the cost imposed by our modern healthcare system. The change is powered by what Topol calls medicine's "Gutenberg moment." Much as the printing press took learning out of the hands of a priestly class, the mobile internet is doing the same for medicine, giving us unprecedented control over our healthcare. With smartphones in hand, we are no longer beholden to an impersonal and paternalistic system in which "doctor knows best." Medicine has been digitized, Topol argues; now it will be democratized. Computers will replace physicians for many diagnostic tasks, citizen science will give rise to citizen medicine, and enormous data sets will give us new means to attack conditions that have long been incurable. Massive, open, online medicine, where diagnostics are done by Facebook-like comparisons of medical profiles, will enable real-time, real-world research on massive populations. There's no doubt the path forward will be complicated: the medical establishment will resist these changes, and digitized medicine inevitably raises serious issues surrounding privacy. Nevertheless, the result-better, cheaper, and more human health care-will be worth it. Provocative and engrossing, The Patient Will See You Now is essential reading for anyone who thinks they deserve better health care. That is, for all of us.
Book Synopsis Fluorine Magnetic Resonance Imaging by : Ulrich Flogel
Download or read book Fluorine Magnetic Resonance Imaging written by Ulrich Flogel and published by CRC Press. This book was released on 2016-10-26 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past decade, fluorine (19F) magnetic resonance imaging (MRI) has garnered significant scientific interest in the biomedical research community owing to the unique properties of fluorinated materials and the 19F nucleus. Fluorine has an intrinsically sensitive nucleus for MRI. There is negligible endogenous 19F in the body and thus there is no background signal. Fluorine-containing compounds are ideal tracer labels for a wide variety of MRI applications. Moreover, the chemical shift and nuclear relaxation rate can be made responsive to physiology via creative molecular design. This book is an interdisciplinary compendium that details cutting-edge science and medical research in the emerging field of 19F MRI. Edited by Ulrich Flögel and Eric Ahrens, two prominent MRI researchers, this book will appeal to investigators involved in MRI, biomedicine, immunology, pharmacology, probe chemistry, and imaging physics.
Book Synopsis Microdosimetry by : Lennart Lindborg
Download or read book Microdosimetry written by Lennart Lindborg and published by CRC Press. This book was released on 2017-07-06 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental microdosimetry deals with the measurement of charged particle energy deposition in tissue equivalent volumes, ranging in size from nanometres to micrometres. Microdosimetry is employed to improve our understanding of the relationship between radiation energy deposition, the resulting biological effects, and the appropriate quantities to be used in characterizing and quantifying radiation quality. Although many reviews and contributions to the field have been published over the past fifty years, this new book is the first to provide a single, up to date, and easily accessible account of experimental microdosimetry. This book is designed to be used in medical, radiation, and health physics courses and by Master’s and PhD students. In addition to serving as an introductory text to the field for graduate students, this book will also be of interest as a teaching and reference resource for graduate supervisors and established researchers. Drs. Lennart Lindborg and Anthony Waker have spent a life-time career in experimental microdosimetry research in academic, industrial and regulatory environments and have observed the development of the field from its early days as a recognized discipline; they bring to this book particular knowledge and experience in the design, construction, operation and use of tissue equivalent gas ionization counters and chambers.
