The past decades have witnessed wide demand and applications for wireless commu- nications in the human body area, that is, in the immediate Environment around a human body. These demands and applications especially focus on wireless transmis- sion and networking of personal information for user identification, healthcare and medical applications.
标签： communications modeling channel Body area
上传时间： 2020-05-26
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Cognitive radio has emerged as a promising technology for maximizing the utiliza- tion of the limited radio bandwidth while accommodating the increasing amount of services and applications in wireless networks. A cognitive radio (CR) transceiver is able to adapt to the dynamic radio Environment and the network parameters to maximize the utilization of the limited radio resources while providing flexibility in wireless access. The key features of a CR transceiver are awareness of the radio envi- ronment (in terms of spectrum usage, power spectral density of transmitted/received signals, wireless protocol signaling) and intelligence.
标签： Cognitive Wireless Network
上传时间： 2020-05-26
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Cooperation has been the subject of intensive study in the social and biological sciences, as well as in mathematics and artificial intelligence. The fundamental finding is that even egoists can sustain cooperation provided the structure of their Environment allows for repeated interactions (Axelrod 1984).
标签： Cooperation Wireless Networks in
上传时间： 2020-05-27
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The telecommunications industry is undoubtedly in a period of radical change with the advent of mobile broadband radio access and the rapid convergence of Internet and mobile services. Some of these changes have been enabled by a fundamental shift in the underlying technologies; mobile networks are now increasingly based on a pure Internet Protocol (IP) network architecture. Since the first edition of this book was published in 2009, a multitude of connected devices from eBook readers to smartphones and even Machine-to-Machine (M2M) technologies have all started to benefit from mobile broadband. The sea change over the last few years is only the beginning of a wave of new services that will fundamentally change our economy, our society, and even our Environment. The evolution towards mobile broadband is one of the core underlying parts of this revolution and is the focus of this book.
标签： Networks Packet EPC and 4G
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Our original effort in writing this book was to create a starting point for those in the business community who did not have a high level of technical expertise but needed to have some understanding of the technical functions of their information and communication technologies (ICT) in a corporate Environment. As was true with the first edition of this book, if you are already an engineer, find some other form of pleasure reading—this text is not designed for you!
标签： Communications Introduction Technologies to
上传时间： 2020-05-27
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Nature is seldom kind. One of the most appealing uses for radio- telephone systems—communication with people on the move—must over- come radio transmission problems so difficult they challenge the imagina- tion. A microwave radio signal transmitted between a fixed base station and a moving vehicle in a typical urban Environment exhibits extreme variations in both amplitude and apparent frequency.
标签： Communications Microwave Mobile
上传时间： 2020-05-28
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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.
标签： Multiple-Output Multiple-Input Channel Models
上传时间： 2020-05-31
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This book on Project Management is intended as a quick reference covering important aspects of project management that should be understood by managers in the telecommunications Environment. This book is organized with an introduction, which introduces the value chain in telecommunications and illustrates the type of project, which one might encounter in a telecommunications company.
标签： Telecommunications Management Managers Project
上传时间： 2020-05-31
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This paper presents a Hidden Markov Model (HMM)-based speech enhancement method, aiming at reducing non-stationary noise from speech signals. The system is based on the assumption that the speech and the noise are additive and uncorrelated. Cepstral features are used to extract statistical information from both the speech and the noise. A-priori statistical information is collected from long training sequences into ergodic hidden Markov models. Given the ergodic models for the speech and the noise, a compensated speech-noise model is created by means of parallel model combination, using a log-normal approximation. During the compensation, the mean of every mixture in the speech and noise model is stored. The stored means are then used in the enhancement process to create the most likely speech and noise power spectral distributions using the forward algorithm combined with mixture probability. The distributions are used to generate a Wiener filter for every observation. The paper includes a performance evaluation of the speech enhancer for stationary as well as non-stationary noise Environment.
标签： Telecommunications Processing Signal for
上传时间： 2020-06-01
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The continuing explosive growth in mobile communication is demanding more spectrally efficient radio access technologies than the prevalent second generation (2G) systems such as GSM to handle just the voice traffic. We are already witnessing high levels of mobile penetration exceeding 70% in some countries. It is anticipated that by 2010 more than half of all communications will be carried out by mobile cellular networks. On the other hand, the information revolution and changing life habits are bringing the requirement of commu- nicating on a multimedia level to the mobile Environment. But the data handling capabilities and flexibility of the 2G cellular systems are limited.
上传时间： 2020-06-01
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