Someone who wants to get to know the customs of a country frequently receives the advice to learn the language of that country. Why? Because the dif- ferences that distinguish the people of one country from those of another are reflected in the language. For example, the people of the islands of the Pacific do not have a term for war in their language. Similarly, some native tribes in the rain forests of the Amazon use up to 100 different terms for the color green.
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This book was conceived in such a special way. From our experience, and despite the increasing interest that we perceived amongst the research community in HAPS, there was not any book in the market entirely devoted to HAPS. We could only find some satellite communications books including only fragments related to HAPS, covering the ‘generalities’. A need for a reference book which could highlight state- of-the-art HAPS-related topics was therefore envisaged. Moreover, most of the information related to HAPS could only be found in technical reports, official recommendations, conference proceedings and journal papers.
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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 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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Fixed-mobile.convergence.and.voice-data.networks.have.merged.next-gen- eration,.value-added.applications.and.integrated.multimedia.services,.com- bining. Web. browsing,. instant. messaging,. presence,. voice. over. IP,. video. conferencing,. application. sharing,. telephony,. unified. messaging,. multi- media.content.delivery,.etc..on.top.of.different.network.technologies..The. convergence.of.the.communications.networks.is.motivated.by.the.need.to. support.many.forms.of.digital.traffic.as.well.as.to.amortize.implementation. and.operational.costs.of.the.underlying.networks..Historically,.the.approach. to. build. and. deploy. multimedia. services. has. focused. upon. single-point. solutions..
标签： Multimedia Subsystem Handbook IMS IP
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This book addresses two aspects of network operation quality; namely, resource management and fault management. Network operation quality is among the functions to be fulfilled in order to offer quality of service, QoS, to the end user. It is characterized by four parameters: – packet loss; – delay; – jitter, or the variation of delay over time; – availability. Resource management employs mechanisms that enable the first three parameters to be guaranteed or optimized. Fault management aims to ensure continuity of service.
标签： Ethernet Networks MPLS and IP
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For nearly a hundred years telecommunications provided mainly voice services and very low speed data (telegraph and telex). With the advent of the Internet, several data services became mainstream in telecommunications; to the point that voice is becoming an accessory to IP-centric data networks. Today, high-speed data services are already part of our daily lives at work and at home (web surfing, e-mail, virtual private networks, VoIP, virtual meetings, chats...). The demand for high-speed data services will grow even more with the increasing number of people telecommuting.
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In the nineteenth century, scientists, mathematician, engineers and innovators started investigating electromagnetism. The theory that underpins wireless communications was formed by Maxwell. Early demonstrations took place by Hertz, Tesla and others. Marconi demonstrated the first wireless transmission. Since then, the range of applications has expanded at an immense rate, together with the underpinning technology. The rate of development has been incredible and today the level of technical and commercial maturity is very high. This success would not have been possible without understanding radio- wave propagation. This knowledge enables us to design successful systems and networks, together with waveforms, antennal and transceiver architectures. The radio channel is the cornerstone to the operation of any wireless system.
标签： LTE-Advanced Generation Next and
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