Download or read book D modulation Aveugle En Interception de Signaux Mimo written by Steredenn DAUMONT and published by Omniscriptum. This book was released on 2018-02-28 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les systèmes MIMO (Multiple Input Multiple Output) ont été proposés par le laboratoire Bell dans les années 90 afin d'augmenter le débit des transmissions. Par la suite, ces systèmes ont été utilisés pour augmenter la fiabilité de la transmission en introduisant de la redondance. L'objectif de cet ouvrage est de proposer des techniques d'estimation, en aveugle, des symboles transmis sur des canaux MIMO. La séparation aveugle de sources, ou BSS pour Blind Source Separation, permet d'estimer les symboles transmis de manière aveugle i.e. sans connaissance du canal de transmission ou de symboles pilotes. Cependant la BSS estime les sources à une rotation et permutation près. D'autres part, les méthodes de BSS utilisant un gradient stochastique sont lentes à converger, ce qui les rend difficilement utilisables sur des canaux variant rapidement dans le temps. Ainsi les axes de recherches sont l'exploitation de la redondance introduite par les codes STBC pour lever des ambiguïtés générées par la BSS, puis l'implémentation de certains critères de manière analytique et enfin l'initialisation d'un filtre de Kalman par la BSS.

Download or read book Techniques de d modulation aveugle en interception de signaux MIMO written by Steredenn Daumont and published by . This book was released on 2009 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les systèmes MIMO ont été proposés par le laboratoire Bell afin d'augmenter le débit des transmissions. Par la suite ces systèmes ont été utilisés pour augmenter la fiabilité de la transmission en utilisant des codes introduisant de la redondance. Cette thèse CIFRE est menée en collaboration entre la société IPSIS-IT Link et l'équipe SCEE de Supélec membre du laboratoire IETR. L’objectif de cette thèse est de proposer des techniques d’estimation, en aveugle, des symboles transmis sur des canaux MIMO. La séparation aveugle de sources, ou BSS pour Blind Source Separation, permet d'estimer de manière aveugle, i.e. sans connaissance du canal de transmission et de symboles pilotes, les symboles transmis. C'est ce type de méthode que nous utiliserons principalement dans cette thèse. Cependant, la BSS estime les sources à une rotation et permutation près. D’autre part, les méthodes de BSS utilisant un gradient stochastique sont lentes à converger, ce qui les rend difficilement utilisables sur des canaux variant rapidement dans le temps. Ainsi, les axes de recherche exploités durant cette thèse sont : - L'exploitation de la redondance introduite par les codes STBC pour lever les ambiguïtés introduites par la BSS. - L’implémentation de certains critères de manière analytique. Les méthodes analytiques implémentées de manière adaptative convergent rapidement dans le temps, permettant ainsi une utilisation sur des canaux qui varient rapidement dans le temps. - L’initialisation du filtre de Kalman, connu pour ses qualités de poursuite, par la séparation aveugle de sources. Ce type d’association permet de poursuivre des canaux instantanés ou convolutifs variant dans le temps.

Download or read book Interception des signaux issus de communications MIMO written by Vincent Choqueuse and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Les communications multi-antennes, désignées par l'acronyme MIMO (Multiple-Input Multiple-Output), permettent d'atteindre des débits et une qualité de transmission élevés en exploitant la diversité spatiale du canal de propagation. De part leurs performances, les systèmes MIMO sont au coeur des futurs standards de réseaux sans- fil et de téléphonie mobile et devraient occuper prochainement une place importante dans le canal hertzien. Cette thèse, intitulée « Interception des signaux issus de communications MIMO », aborde ces systèmes dans le contexte non coopératif c'est-à-dire lorsque le récepteur ne dispose d'aucune information sur la configuration de l'émetteur, le canal de propagation et sur le niveau de bruit. L'étude se situe en aval des étapes de synchronisation et suppose que les échantillons reçus sont préalablement ramenés en bande de base et échantillonnés au rythme d'un échantillon par symbole. Sous ces hypothèses, nous proposons plusieurs algorithmes pour identifier en aveugle les paramètres de l'émetteur tels que le nombre d'antennes, le codage spatio-temporel et la modulation. Les applications concernées sont variées et touchent aussi bien le domaine civil (développement de récepteurs MIMO auto-configurants) que le domaine militaire

Download or read book S paration et reconnaissance des signaux d interception en t l communications written by Maciej Pedzisz and published by . This book was released on 2006 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cette thèse aborde le contexte de la surveillance civile ou de la Guerre Électronique, où l'on peut être confronté aux problèmes de reconnaissance automatique et de séparation aveugle de plusieurs modulations. Elle s’articule autour de 3 parties principales. La première, traite les problèmes liés à la synchronisation des fréquences porteuses. Ces problèmes résultent de la méconnaissance de la modulation utilisée et de la précision insuffisante des méthodes d’estimation spectrale classiques (signaux multi- composantes). Deux nouvelles approches sont proposées pour stabiliser les constellations des signaux captés. La deuxième partie introduit deux algorithmes de reconnaissance automatique de modulations numériques. Ces algorithmes sont basés sur de nouvelles caractéristiques distinctives afin d’assurer la classification préliminaire ainsi que la classification raffinée. Les résultats expérimentaux ont montré que les deux méthodes sont capables de classifier correctement des modulations de type MPSK, MQAM et MFSK, et peuvent être facilement mises en œuvre pour d'autres types de signaux. Enfin, dans la troisième partie, la séparation aveugle des mélanges convolutifs indéterminés est abordée. En se basant sur une seule observation d'un mélange de deux signaux numériques, un nouveau critère de séparation, ainsi qu'une nouvelle structure d'un récepteur-séparateur sont proposés. Grâce à cette nouvelle structure, il devient possible d'estimer simultanément les réponses impulsionnelles des filtres d'émission et des canaux de transmission, ainsi que les suites de symboles émis par les deux sources.

Download or read book Automatic Modulation Classification written by Zhechen Zhu and published by John Wiley & Sons. This book was released on 2015-02-16 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Automatic Modulation Classification (AMC) has been a key technology in many military, security, and civilian telecommunication applications for decades. In military and security applications, modulation often serves as another level of encryption; in modern civilian applications, multiple modulation types can be employed by a signal transmitter to control the data rate and link reliability. This book offers comprehensive documentation of AMC models, algorithms and implementations for successful modulation recognition. It provides an invaluable theoretical and numerical comparison of AMC algorithms, as well as guidance on state-of-the-art classification designs with specific military and civilian applications in mind. Key Features: Provides an important collection of AMC algorithms in five major categories, from likelihood-based classifiers and distribution-test-based classifiers to feature-based classifiers, machine learning assisted classifiers and blind modulation classifiers Lists detailed implementation for each algorithm based on a unified theoretical background and a comprehensive theoretical and numerical performance comparison Gives clear guidance for the design of specific automatic modulation classifiers for different practical applications in both civilian and military communication systems Includes a MATLAB toolbox on a companion website offering the implementation of a selection of methods discussed in the book

Download or read book Geolocation of RF Signals written by Ilir Progri and published by Springer Science & Business Media. This book was released on 2011-01-15 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geolocation of RF Signals—Principles and Simulations offers an overview of the best practices and innovative techniques in the art and science of geolocation over the last twenty years. It covers all research and development aspects including theoretical analysis, RF signals, geolocation techniques, key block diagrams, and practical principle simulation examples in the frequency band from 100 MHz to 18 GHz or even 60 GHz. Starting with RF signals, the book progressively examines various signal bands – such as VLF, LF, MF, HF, VHF, UHF, L, S, C, X, Ku, and, K and the corresponding geolocation requirements per band and per application – to achieve required performance objectives of up to 0o precision. Part II follows a step-by-step approach of RF geolocation techniques and concludes with notes on state-of-the-art geolocation designs as well as advanced features found in signal generator instruments. Drawing upon years of practical experience and using numerous examples and illustrative applications, Ilir Progri provides a comprehensive introduction to Geolocation of RF Signals, and includes hands-on real world labs and applications using MATLAB in the areas of: RF signals specifications, RF geolocation distributed wireless communications networks and RF geolocation. Geolocation of RF Signals—Principles and Simulations will be of interest to government agency program managers industry professionals and engineers, academic researchers, faculty and graduate students who are interested in or currently designing, developing and deploying innovative geolocation of RF Signal systems.

Download or read book Indoor Geolocation Systems written by Ilir F. Progri and published by Springer. This book was released on 2015-02-19 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this book is introduce and discuss indoor geolocation systems —theory and applications for over 20 years. The first part of the book is dedicated to the theory of indoor geolocation systems, which consists of five chapters. In the first chapter, geolocation systems is introduced. In the second chapter, the state-of-the-art radio geolocation systems are classified. Illustrations include GPS and GLONASS. The third chapter deals with the issues of identity with the state-of-the-art indoor geolocation systems Giftet Inc., Locatalite, GPS repeaters, the Integrinautics pseudolite as to obtaining an observable or several observables for indoor geolocation. The fourth chapter consists of a detailed discussion on fixed and Doppler-based navigation algorithms suitable for indoor geolocaiton systems and advanced signal processing techniques for indoor geolocation receiver design, which includes Maximum Likelihood Receiver and Bayesian Monte Carlo Markov Chain. Chapter 5 (or the last chapter of part 1 or of the theory) discusses the indoor geolocaiton channel and proposes a mathematical model for the unified geolocation channel.

Download or read book Automatic Modulation Recognition of Communication Signals written by Elsayed Azzouz and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: Automatic modulation recognition is a rapidly evolving area of signal analysis. In recent years, interest from the academic and military research institutes has focused around the research and development of modulation recognition algorithms. Any communication intelligence (COMINT) system comprises three main blocks: receiver front-end, modulation recogniser and output stage. Considerable work has been done in the area of receiver front-ends. The work at the output stage is concerned with information extraction, recording and exploitation and begins with signal demodulation, that requires accurate knowledge about the signal modulation type. There are, however, two main reasons for knowing the current modulation type of a signal; to preserve the signal information content and to decide upon the suitable counter action, such as jamming. Automatic Modulation Recognition of Communications Signals describes in depth this modulation recognition process. Drawing on several years of research, the authors provide a critical review of automatic modulation recognition. This includes techniques for recognising digitally modulated signals. The book also gives comprehensive treatment of using artificial neural networks for recognising modulation types. Automatic Modulation Recognition of Communications Signals is the first comprehensive book on automatic modulation recognition. It is essential reading for researchers and practising engineers in the field. It is also a valuable text for an advanced course on the subject.

Download or read book Digital Communication over Fading Channels written by Marvin K. Simon and published by John Wiley & Sons. This book was released on 2005-02-11 with total page 936 pages. Available in PDF, EPUB and Kindle. Book excerpt: The four short years since Digital Communication over Fading Channels became an instant classic have seen a virtual explosion of significant new work on the subject, both by the authors and by numerous researchers around the world. Foremost among these is a great deal of progress in the area of transmit diversity and space-time coding and the associated multiple input-multiple output (MIMO) channel. This new edition gathers these and other results, previously scattered throughout numerous publications, into a single convenient and informative volume. Like its predecessor, this Second Edition discusses in detail coherent and noncoherent communication systems as well as a large variety of fading channel models typical of communication links found in the real world. Coverage includes single- and multichannel reception and, in the case of the latter, a large variety of diversity types. The moment generating function (MGF)-based approach for performance analysis, introduced by the authors in the first edition and referred to in literally hundreds of publications, still represents the backbone of the book's presentation. Important features of this new edition include: * An all-new, comprehensive chapter on transmit diversity, space-time coding, and the MIMO channel, focusing on performance evaluation * Coverage of new and improved diversity schemes * Performance analyses of previously known schemes in new and different fading scenarios * A new chapter on the outage probability of cellular mobile radio systems * A new chapter on the capacity of fading channels * And much more Digital Communication over Fading Channels, Second Edition is an indispensable resource for graduate students, researchers investigating these systems, and practicing engineers responsible for evaluating their performance.

Download or read book The Mobile Radio Propagation Channel written by J. D. Parsons and published by Wiley. This book was released on 1996-03-01 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offers in-depth discussions of multipath phenomena and its effects on narrowband and wideband signals. Presents basic information about the mobile radio channel and introduces some fundamental VHF and UHF propagation. Surveys signal strength prediction methods applicable over irregular terrain and in urban, suburban and rural areas as well as methods of channel sounding and simulation.