OSCILLATORS are key building blocks in integrated transceivers. In wired and wireless communication terminals, the receiver front-end selects, amplifies and converts the desired high-frequency signal to baseband. At baseband the signal can then be converted into the digital domain for further data processing and demodula- tion. The transmitter front-end converts an analog baseband signal to a suitable high- frequency signal that can be transmitted over the wired or wireless channel.
标签： High-Frequency Oscillator Design
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The motivation to write about the History of Wireless comes from Auguste Comte (1798-1857), a French philosopher who is termed the father of positivism and modem sociology [Les Maximes d'Auguste Comte (Auguste Comte's Mottos), http://www.membres.lycos.fr/clotilde/l: On ne connaitpas complgtement une science tant qu'on n'en saitpas l'histoire. (One does not know completely a science as long as one does not know its history.)
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The first Third Generation Partnership Project (3GPP) Wideband Code Division Multiple Access (WCDMA) networks were launched during 2002. By the end of 2005 there were 100 open WCDMA networks and a total of over 150 operators having frequency licenses for WCDMA operation. Currently, the WCDMA networks are deployedinUniversalMobileTelecommunicationsSystem(UMTS)bandaround2GHz in Europe and Asia including Japan and Korea. WCDMA in America is deployed in the existing 850 and 1900 spectrum allocations while the new 3G band at 1700/2100 is expected to be available in the near future. 3GPP has defined the WCDMA operation also for several additional bands, which are expected to be taken into use during the coming years.
标签： HSDPAHSUPA Access Speed Radio UMTS High for
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In this paper we revisit hybrid analog-digital precoding systems with emphasis on their modelling and radio-frequency (RF) losses, to realistically evaluate their benefits in 5G system implementations. For this, we decompose the analog beamforming networks (ABFN) as a bank of commonly used RF components and formulate realistic model constraints based on their S-parameters. Specifically, we concentrate on fully-connected ABFN (FC-ABFN) and Butler networks for implementing the discrete Fourier transform (DFT) in the RF domain. The results presented in this paper reveal that the performance and energy efficiency of hybrid precoding systems are severely affected, once practical factors are considered in the overall design. In this context, we also show that Butler RF networks are capable of providing better performances than FC-ABFN for systems with a large number of RF chains.
标签： Analog-Digital Precoding Hybrid
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Communication, a word that many associate with modern technology, actually has nothing to do with technology. At its core, communication involves nothing more than the spoken or written word, and symbolic languages like art and music. Technology has become synonymous with communication because technology has historically been the method by which communication to or by the general population takes place.
标签： Implementing 802.11
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This preface is somewhat different from prefaces found in similar books because it does not focus so much on the content of the book.We have instead chosen to write a few words about our own experiences from working with telephony services over Internet Protocol (IP). Here are our stories.
标签： Multimedia Telephony Cellular Systems over IMS
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This book is intended for RF planners, to serve as a practical tool in their daily work designing indoor radio distribution systems. Based on feedback from readers of the first edition it was clear to me that I needed to add more material and in depth description of the basics of indoor systems based on using repeaters; this has grown into a new Section 4.7. There was also a strong demand to add more detail and dedicate a full chapter to radio planning in tunnels, for both rail and road tunnels; and redundancy principles in the design focus for solving the challenge of handover zones. An entire Chapter 11 is now dedicated to tunnel radio planning.
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This book is intended for the RF planners, to serve as a practical tool in their daily work designing indoor radio distribution systems. It is not a complete book about all the deep aspects and corners of GSM, DCS, UMTS and HSPA networks, or all the core network systems. It is dedicated to the last 10–70 m of the network, the indoor air interface between the mobile user and the indoor mobile network.
标签： Practical Planning Indoor Guide Radio GSM for
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The information technology (IT) revolution is surely coming in this century, just as did the agricultural and industrial revolutions that have already so enriched our lives. As the IT revolution progresses, it is expected that almost all social struc- tures and economic activities will be changed substantially
标签： Communication Intelligent Systems
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When digital media is perceived only as a tool to deliver content the potential for using its affordances to explore meaning is lost. Rather than seeing media only as an access point, we can view it as a way to enhance the expressiveness of content. Today blogs, wikis, messaging, mash-ups, and social media (Facebook, Twitter, YouTube and others) offer authors ways to create narrative meaning that refl ects our new media culture. We can look to the past for similarities and parallels to better understand how to use social media as a creative tool with which to dialogue, collaborate, and create interactive narratives.
标签： Interactivity Social Media in
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