According to the statistics of the Federal Communications Commission (FCC), temporal and geographical variations in the utilization of the as- signed spectrum range from 15% to 85%. The limited available radio spec- trum and the inefficiency in spectrum usage necessitate a new commu- nication paradigm to exploit the existing spectrum dynamically.
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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
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The term economics is generally understood to mean sound management. This is associated with openness, good faith, accurate figures and integrity in company accounts, with transparency ensured through satisfactory standards of good practice in relation to investors and the clients who have placed their trust in an organization’s managers.
标签： Communication NETWORKs Economy
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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
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At the time of writing, and to an extent never seen before, there is an expectation that almost any information or service that is available through communication systems in the office or home will be available wherever the user happens to be. This is placing incredible demands on wireless communications and has been the driver for the gen- esis and deployment of three generations of cellular systems in the space of 20 years.
标签： Deploying Wireless NETWORKs
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The new digital radio system DAB (Digital Audio Broadcasting, nowadays often called Digital Radio) is a very innovative and universal multimedia broadcast system which will replace the existing AM and FM audio broadcast services in many parts of the world in the future. It was developed in the 1990s by the Eureka 147/DAB project. DAB is very well suited for mobile reception and provides very high robustness against multipath reception. It allows use of single frequency NETWORKs (SFNs) for high frequency efficiency.
标签： Broadcasting Principles Digital Audio
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This thesis is about wireless communication in shared radio spectrum. Its origin and motivation is ideally represented by the two quotations from above. In this thesis, the support of Quality-of-Service (QoS) in cognitive radio NETWORKs is analyzed. New approaches to distributed coordination of cognitive radios are developed in different spectrum sharing scenarios. The Wireless Local Area Network (WLAN) 802.11 proto- col of the Institute of Electrical and Electronics Engineers (IEEE) (IEEE, 2003) with its enhancement for QoS support (IEEE, 2005d) is taken as basis. The Medium Access Control (MAC) of 801.11(e) is modified to realize flexible and dynamic spectrum assignment within a liberalized regulation framework.
标签： Quality-of-Service Distributed Support
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A series of features makes the mobile telecommunications industry an interesting field of investigation for economists: the industry is experi- encing veryfastmarketgrowthcombinedwithrapidtechnological change; regulatory design in setting market structure is playing a very important role; and oligopolistic competition is unfolding under various forms. The number of subscribers to mobile NETWORKs is growing at a rapid rate on a worldwide basis, as shown in figure 1.1.
标签： Telecommunications Economics Mobile of
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When joining Siemens in 2001, I also extended my research interest towards radio net- work planning methodologies. This area of research brought together my personal interest in mobile communications and in the design of efficient algorithms and data structures. Between 2001 and 2003, I participated in the EU project Momentum, which was target- ing the performance evaluation and optimization of UMTS radio NETWORKs. I
标签： Efficient Methods WCDMA for
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With the advancement of technology and miniaturization of electronic devices, applications of wireless sensor NETWORKs (WSNs) can be seen in diverse areas in our lives. In fact, these WSNs have gained a lot of attention from both the research community and industry, making them easily available on the market. An extensive amount of research, easy availability, and cheap cost make them useful in various types of futuristic applications as well.
标签： Communication Technologies Emerging
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