In general there are three different techniques for performance evaluation of systems and networks: mathematical analysis, measurements, and computer simulation. All These techniques have their strength and weaknesses. In the literature there are plenty of discussions about when to use which technique, how to apply it, and which pitfalls are related to which evaluation technique.
標簽： Simulation Modeling Network Tools and for
上傳時間： 2020-05-31
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Many wireless communications channels consist of multiple signal paths from the transmitter to receiver. This multiplicity of paths leads to a phenomenon known as multipath fading. The multiple paths are caused by the presence of objects in the physical environment that, through the mechanisms of propagation, alter the path of radiated energy. These objects are referred to as scatterers. In the past, researchers often looked at ways to mitigate multipath scattering, such as in diversity systems. Multiple-input, multiple-output (MIMO) systems, on the other hand, use multipath diversity to their advantage; a MIMO system has the ability to translate increased spatial diversity into increased channel capacity.
標簽： Multiple-Output Multiple-Input Channel Models
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European Research Framework programs are public policy instruments designed to strengthen European competitiveness through cooperation. Although they have a fixed time frame, determined research themes, and a specific expected impact, the achievements in research and development (R&D) made by These funded proj- ects pave the way for a research continuum.
標簽： Communications Horizons Wireless Mobile New and in
上傳時間： 2020-05-31
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In the past few decades, a technological revolution has occurred that has changed the way we live in dramatic ways. This technological revolution is the result of the emergence and evolution of a wide variety of new wireless networking tech- nologies. Now people using These technologies are able to access the network and control many applications at will with their handheld devices anywhere, anytime. Although These technologies have made a long lasting impact in the revolution, it has also opened up various challenging issues which are yet to be resolved to make them more efficient and cost-effective.
標簽： Next-Generation Technologies Wireless
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The roots of this book were planted about a decade ago. At that time, I became increasingly convinced that wide-area and metropolitan-area networks, where much of my group’s research has been centered at that time, were in good shape. Although research in These fields was (and still is) needed, that’s not where the networking bottleneck seemed to be. Rather, the bottleneck was (and still is in many places) in the access networks, which choked users’ access to information and services. It was clear to me that the long-term solution to that problem has to involve optical fiber access networks.
上傳時間： 2020-05-31
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The ever-increasing demand for private and sensitive data transmission over wireless net- works has made security a crucial concern in the current and future large-scale, dynamic, and heterogeneous wireless communication systems. To address this challenge, computer scientists and engineers have tried hard to continuously come up with improved crypto- graphic algorithms. But typically we do not need to wait too long to find an efficient way to crack These algorithms. With the rapid progress of computational devices, the current cryptographic methods are already becoming more unreliable. In recent years, wireless re- searchers have sought a new security paradigm termed physical layer security. Unlike the traditional cryptographic approach which ignores the effect of the wireless medium, physi- cal layer security exploits the important characteristics of wireless channel, such as fading, interference, and noise, for improving the communication security against eavesdropping attacks. This new security paradigm is expected to complement and significantly increase the overall communication security of future wireless networks.
標簽： Communications Physical Security Wireless Layer in
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This book is a result of the recent rapid advances in two related technologies: com- munications and computers. Over the past few decades, communication systems have increased in complexity to the point where system design and performance analysis can no longer be conducted without a significant level of computer sup- port. Many of the communication systems of fifty years ago were either power or noise limited. A significant degrading effect in many of These systems was thermal noise, which was modeled using the additive Gaussian noise channel.
標簽： Communication Principles Simulation Systems of
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Communication has been one of the deepest needs of the human race throughout recorded history. It is essential to forming social unions, to educating the young, and to expressing a myriad of emotions and needs. Good communication is central to a civilized society. The various communication disciplines in engineering have the purpose of providing technological aids to human communication. One could view the smoke signals and drum rolls of primitive societies as being technological aids to communication, but communication technology as we view it today became important with telegraphy, then telephony, then video, then computer communication, and today the amazing mixture of all of These in inexpensive, small portable devices.
標簽： communication Principles digital of
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Wireless means different things to different people. For this book, it refers to the radio systems that provide point-to-point, point-to-multipoint, and Earth-space communications over transmission links that propagate outside buildings through the lower atmosphere. Wireless systems are being built that provide data transmission between computers and other devices on one’s own desk. These are part of the wireless world but not the part where, except for interference perhaps, the atmosphere has any influence. The intent of this book is to provide a description of the physical phenomena that can affect propagation through the atmosphere, present sample measurements and statistics, and provide models that system designers can use to calculate their link budgets and estimate the limitations the atmosphere may place on their design.
標簽： Communication Propagation Handbook Wireless for
上傳時間： 2020-05-31
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This book provides the essential design techniques for radio systems that operate at frequencies of 3 MHz to 100 GHz and which will be employed in the telecommunication service. We may also call These wireless systems, wireless being synonymous with radio, Telecommunications is a vibrant indus- try, particularly on the ‘‘radio side of the house.’’ The major supporter of this upsurge in radio has been the IEEE and its 802 committees. We now devote ? . an entire chapter to wireless LANs WLANs detailed in IEEE 802.11. We also now have subsections on IEEE 802.15, 802.16, 802.20 and the wireless ? . ? metropolitan area network WMAN . WiFi, WiMax,, and UWB ultra wide- . band are described where These comparatively new radio specialties are demonstrating spectacular growth.
標簽： Telecommunication Design System Radio for
上傳時間： 2020-06-01
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