Wireless technology has been evolving at a breakneck speed. The total number of cell-phones in use (as of 2011) was over 6 billion for a 7 billion world population [1] constituting 87% of the world population. Additionally, with user convenience be- coming paramount, more and more functions are being implemented wirelessly.
标签： Front-Ends Cognitive Receiver Radio
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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 capability of radio waves to provide almost instantaneous distant communications without interconnecting wires was a major factor in the explosive growth of communica- tions during the 20th century. With the dawn of the 21st century, the future for communi- cations systems seems limitless. The invention of the vacuum tube made radio a practical and affordable communications medium.
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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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The General Packet Radio Service (GPRS) allows an end user to send and receive data in packet transfer mode within a public land mobile network (PLMN) without using a permanent connection between the mobile station (MS) and the external network during data transfer. This way, GPRS opti- mizes the use of network and radio resources (RRs) since, unlike circuit- switched mode, no connection between the MS and the external network is established when there is no data flow in progress. Thus, this RR optimiza- tion makes it possible for the operator to offer more attractive fees.
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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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Following chapter introduces the mobile communication, gives a short history of wireless communication evolution, and highlights some application scenarios predestined for the use of mobile devices. Cellular and wireless based systems related to different generations of mobile communication, including GSM, IS-95, PHS, AMPS, D-AMPS, cdma2000 and WCDMA are also described by this Chapter. Much attention in this chapter is given to express the wireless based networks, such as Wi-Fi and WiBro/WiMax, and wireless broadcasting systems, including DMB, DVB-H, and ISDB-T. We conclude the chapter with the future vision of mobile communication evolution
标签： Technologies Enhanced Access Radio
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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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Providing QoS while optimizing the LTE network in a cost efficient manner is very challenging. Thus, radio scheduling is one of the most important functions in mobile broadband networks. The design of a mobile network radio scheduler holds several objectives that need to be satisfied, for example: the scheduler needs to maximize the radio performance by efficiently distributing the limited radio re- sources, since the operator’s revenue depends on it.
标签： Communications Future Mobile LTE
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Currently, the information and communications technology (ICT) industry sector accounts for about 2–6% of the energy consumption worldwide, and a significant por- tion of this is contributed by the wireless and mobile communications industry. With the proliferation of wireless data applications, wireless technology continues to increase worldwide at an unprecedented growth rate. This has resulted in an increased number of installed base stations and higher demand on power grids and device power usage, causing an increased carbon footprint worldwide.
标签： Communication Networks Green Radio
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