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.
標簽： Networks Packet EPC and 4G
上傳時間： 2020-05-27
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Mobile multimedia communication is increasingly in demand because of the basic need to communi- cate at any time, anywhere, using any technology. In addition, to voice communication, people have a desire to access a range of other services that comprise multimedia elements—text, image, animation, high fidelity audio and video using mobile communication networks. To meet these demands, mobile communication technologies has evolved from analog to digital, and the networks have passed through a number of generations from first generation (1G) to fourth generation (4G).
標簽： Communications Multimedia Concepts Mobile
上傳時間： 2020-05-30
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The roots of this book were planted about a decade ago. At that time, I became increasingly convinced that wide-area and metropolitan-area networks, where much of my group’s research has been centered at that time, were in good shape. Although research in these fields was (and still is) needed, that’s not where the networking bottleneck seemed to be. Rather, the bottleneck was (and still is in many places) in the access networks, which choked users’ access to information and services. It was clear to me that the long-term solution to that problem has to involve optical fiber access networks.
上傳時間： 2020-05-31
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Ever since ancient times, people continuously have devised new techniques and technologies for communicating their ideas, needs, and desires to others. Thus, many forms of increasingly complex communication systems have appeared over the years. The basic motivations behind each new one were to improve the transmission fidelity so that fewer errors occur in the received message, to increase the transmission capacity of a communication link so that more infor- mation could be sent, or to increase the transmission distance between relay sta- tions so that messages can be sent farther without the need to restore the signal fidelity periodically along its path.
標簽： Communications Essentials Optical
上傳時間： 2020-05-31
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Recent decades have shown a tremendous expansion of the Internet. The number of connected terminals has increased by orders of magnitude, traffic has grown exponen- tially, coverage has become ubiquitous and worldwide, and today’s sophisticated Web 2.0 applications are increasingly providing services which hitherto have been the realm of telecommunications, such as Skype and video conferencing. This has even led to the thought that access to the Internet might one day be a universal right of every citizen. This evolution will accelerate in the coming decades.
標簽： Networking Personal Networks Wireless
上傳時間： 2020-05-31
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Commoditization is a serious threat to the telecommunications industry. Most CSPs offer similar services at rates designed to win what has become a price war. As a result, many face decreasing margins and difficulty sustaining differentiation based on prices or products alone. On top of commoditization, CSPs also face competition from OTT providers and an increasingly knowledgeable and demanding customer base. With access to growing amounts of data from an ever-increasing number of sources and devices, today’s empowered, savvy consumers know what they want and expect to get it.
標簽： RestoringConnections_IBM_CPL
上傳時間： 2020-06-01
上傳用戶：shancjb
A mobile ad-hoc network (MANET) is formed by multiple moving nodes equipped with wireless transceivers. The mobile nodes communicate with each other through multi-hop wireless links, where every node can transmit and receive information. Mobile ad-hoc networks have become increasingly important in areas where deployment of communications infrastructure is difficult.
標簽： Telecommunications Modeling
上傳時間： 2020-06-01
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Wireless communication has become increasingly important not only for professional appli- cations but also for many fields in our daily routine and in consumer electronics. In 1990, a mobile telephone was still quite expensive, whereas today most teenagers have one, and they use it not only for calls but also for data transmission. More and more computers use wireless local area networks (WLANs), and audio and television broadcasting has become digital.
標簽： Applications and Theory OFDM CDMA of
上傳時間： 2020-06-01
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Wireless communications has become a field of enormous scientific and economic interest. Recent success stories include 2G and 3G cellular voice and data services (e.g., GSM and UMTS), wireless local area networks (WiFi/IEEE 802.11x), wireless broadband access (WiMAX/IEEE 802.16x), and digital broadcast systems (DVB, DAB, DRM). On the physical layer side, traditional designs typically assume that the radio channel remains constant for the duration of a data block. However, researchers and system designers are increasingly shifting their attention to channels that may vary within a block. In addition to time dispersion caused by multipath propagation, these rapidly time-varying channels feature frequency dispersion resulting from the Doppler effect. They are, thus, often referred to as being “doubly dispersive.”
標簽： Time-Varying Channels
上傳時間： 2020-06-01
上傳用戶：shancjb
Recent advances in wireless communication technologies have had a transforma- tive impact on society and have directly contributed to several economic and social aspects of daily life. increasingly, the untethered exchange of information between devices is becoming a prime requirement for further progress, which is placing an ever greater demand on wireless bandwidth. The ultra wideband (UWB) system marks a major milestone in this progress. Since 2002, when the FCC allowed the unlicensed use of low-power, UWB radio signals in the 3.1–10.6GHz frequency band, there has been significant synergistic advance in this technology at the cir- cuits, architectural and communication systems levels. This technology allows for devices to communicate wirelessly, while coexisting with other users by ensuring that its power density is sufficiently low so that it is perceived as noise to other users.
上傳時間： 2020-06-01
上傳用戶：shancjb
