A wireless communication network can be viewed as a collection of nodes, located in some domain, which can in turn be transmitters or receivers (depending on the network considered, nodes may be mobile users, base stations in a cellular network, access points of a WiFi mesh etc.). At a given time, several nodes transmit simultaneously, each toward its own receiver. Each transmitter–receiver pair requires its own wireless link. The signal received from the link transmitter may be jammed by the signals received from the other transmitters. Even in the simplest model where the signal power radiated from a point decays in an isotropic way with Euclidean distance, the geometry of the locations of the nodes plays a key role since it determines the signal to interference and noise ratio (SINR) at each receiver and hence the possibility of establishing simultaneously this collection of links at a given bit rate. The interference seen by a receiver is the sum of the signal powers received from all transmitters, except its own transmitter.
标签： Stochastic Geometry Networks Wireless Volume and II
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Before I can present design concepts or tactical wireless communications and network challenges, I feel the need to mention the challenges of writing for a field where some information is not available for public domain and cannot be included in this book’s context. Another challenge is the use of military jargon and the extensive number of abbreviations (and abbreviations of abbreviations!) in the field. Engineering books are naturally dry, and I have attempted to make it light by presenting the concepts in layman’s terms before diving into the technical details. I am structuring this book in such a way as to make it useful for a specialized graduate course in tactical communications and networking, or as a reference book in the field.
标签： Communications Tactical Networks Wireless and
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Intensive development of digital technologies coincided in time with the beginning of the new era in telecommunications. It made possible to formalize many proce- dures of data exchange and to atomize some operations which made providing of serviceandmakeworkofmanytelecommunicationworkersmucheasier. Somenew telecommunication technologies were born out of the necessity for use of specific configurations of network elements and networks, as well as for a possibility of providing maximum characteristics of efficiency combined with high requirements to the stability of operation, the overcoming of different catastrophic situations and deadlockconditions,such as failuresand ”pending”of the networkandthe like. The thresholdbetweeninformationsystems andtelecommunicationsystems has become practically invisible. It resulted in such a new term as ”infocommunication”
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I love telecommunications. It is powerful and it empowers, with far-reaching consequences. It has demonstrated the potential to transform society and business, and the revolution has only just begun. With the invention of the telephone, human communications and commerce were forever changed: Time and distance began to melt away as a barrier to doing business, keeping in touch with loved ones, and being able to immediately respond to major world events. Through the use of computers and telecommunications networks, humans have been able to extend their powers of thinking, influence, and productivity, just as those in the Industrial Age were able to extend the power of their muscles, or physical self, through use of heavy machinery.
标签： Telecommunications Essentials
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A mobile ad-hoc network (MANET) is formed by multiple moving nodes equipped with wireless transceivers. The mobile nodes communicate with each other through multi-hop wireless links, where every node can transmit and receive information. Mobile ad-hoc networks have become increasingly important in areas where deployment of communications infrastructure is difficult.
标签： Telecommunications Modeling
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Rapid progress in information and communications technology (ICT) induces improved and new telecommunications services and contributes greatly to society in general and to vendors and network and service providers. In addition to existing services such as telephony or leased line services, spread of the Internet, the Internet Protocol (IP) phone, and new communications services like IPTV are making great progress with the development of digital subscriber lines (DSL) and high - speed communications technologies like fi ber to the home (FTTH).
标签： Telecommunications Networks
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When 3GPP started standardizing the IMS a few years ago, most analysts expected the number of IMS deploymentsto grow dramatically as soon the initial IMS specifications were ready (3GPP Release 5 was functionallyfrozenin the first half of 2002and completedshortly after that). While those predictions have proven to be too aggressive owing to a number of upheavals hitting the ICT (Information and Communications Technologies) sector, we are now seeing more and more commercial IMS-based service offerings in the market. At the time of writing (May 2008), there are over 30 commercial IMS networks running live traffic, addingup to over10million IMS users aroundthe world; the IMS is beingdeployedglobally. In addition, there are plenty of ongoing market activities; it is estimated that over 130 IMS contracts have been awarded to all IMS manufacturers. The number of IMS users will grow substantially as these awarded contracts are launched commercially. At the same time, the number of IMS users in presently deployed networks is steadily increasing as new services are introduced and operators running these networks migrate their non-IMS users to their IMS networks.
标签： Multimedia Subsystem The IMS 3G IP
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When thinking about mobile radio engineers there is a tendency to assume that the engineering function relates solely to the technical aspects of the network, such as the equipment design or the network design. That is certainly a key part of the role of a mobile radio engineer. However,increasinglyengineersarerequiredtointeractwithprofession- als from other divisions. The “complete wireless professional” should know about mobile networks; fixed networks; other types of mobile systems; regulatory and government policy; the requirements of the users; and financial, legal, and marketing issues.
标签： Communications Complete Wireless The
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The first practical examples of mobile communications were used in many countries like the USA, the UK and Germany in military services, and played a significant role in the First World War to transfer important information from the front to headquarters to take further actions. Good and secure wireless communications were an important need for all military services – army, navy and air force. In this respect, the Second World War was a big experimental battlefield for the development and evolution of mobile radio. It was in the interests of governments that after the Second World War the military investment should be paid back by civilian use, and all western European countries started their so-called first generation of mobile communication networks.
标签： Multimedia Business Mobile The
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Wireless communication has become increasingly important not only for professional appli- cations but also for many fields in our daily routine and in consumer electronics. In 1990, a mobile telephone was still quite expensive, whereas today most teenagers have one, and they use it not only for calls but also for data transmission. More and more computers use wireless local area networks (WLANs), and audio and television broadcasting has become digital.
标签： Applications and Theory OFDM CDMA of
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