This book is a result of the recent rapid advances in two related technologies: com- munications and computers. Over the past few decades, communication systems have increased in complexity to the point where system design and performance analysis can no longer be conducted without a significant level of computer sup- port. Many of the communication systems of fifty years ago were either power or noise limited. A significant degrading effect in many of these systems was thermal noise, which was modeled using the additive Gaussian noise channel.
标签： Communication Principles Simulation Systems of
上传时间： 2020-05-31
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It was only a few years ago that “ubiquitous connectivity” was recognized as the future of wireless communication systems. In the era of ubiquitous connectivity, it was expected that the broadband mobile Internet experience would be pervasive, and seamless connectivity on a global scale would be no surprise at all. The quality of service would be guaranteed no matter when/where/what the users wanted with the connectivity. Connectivity would even be extended to object-to-object communication, where no human intervention was required. All objects would become capable of autonomous communication.
标签： Protocols Radio LTE-A LTE for and
上传时间： 2020-06-01
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The first gem of wisdom I ever acquired about consulting, obtained many years ago from a former schoolmate, was to ensure that everything is plugged in: no continuity, no data. Wires carry voltages and currents from one place to another. Their behavior is reasonably simple and predictable—at least for sufficiently low data rates and short lengths—and they can be seen, grabbed, traced, and tugged.
标签： RF Engineering
上传时间： 2020-06-01
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When 3GPP started standardizing the IMS a few years ago, most analysts expected the number of IMS deploymentsto grow dramatically as soon the initial IMS specifications were ready (3GPP Release 5 was functionallyfrozenin the first half of 2002and completedshortly after that). While those predictions have proven to be too aggressive owing to a number of upheavals hitting the ICT (Information and Communications Technologies) sector, we are now seeing more and more commercial IMS-based service offerings in the market. At the time of writing (May 2008), there are over 30 commercial IMS networks running live traffic, addingup to over10million IMS users aroundthe world; the IMS is beingdeployedglobally. In addition, there are plenty of ongoing market activities; it is estimated that over 130 IMS contracts have been awarded to all IMS manufacturers. The number of IMS users will grow substantially as these awarded contracts are launched commercially. At the same time, the number of IMS users in presently deployed networks is steadily increasing as new services are introduced and operators running these networks migrate their non-IMS users to their IMS networks.
标签： Multimedia Subsystem The IMS 3G IP
上传时间： 2020-06-01
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Some tine ago it become apparent the the first edition of this book was rapidly approaching its sell-by date,since many aspects needed revise.There were two obvious courses of action : to forget the whole thing and concentrate my energies on other pursuits such as golf or fishing, or to embark on a new edition.For several reasons Iwas persuaded that a new edition was a worthwhile endeavour;many people had made complimentary remakrs or written complinentary letters about the first edition and I understood that it had become a recommended text for several postgraduate coures.
标签： TMobile Radio Propagation Channel
上传时间： 2020-06-01
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Having dealt with in-depth analysis of SS#7, GSM and GPRS networks I started to monitor UTRAN interfaces approximately four years ago. Monitoring interfaces means decoding the data captured on the links and analysing how the different data segments and messages are related to each other. In general I wanted to trace all messages belonging to a single call to prove if the network elements and protocol entities involved worked fine or if there had been failures or if any kind of suspicious events had influenced the normal call proceeding or the call’s quality of service. Cases showing normal network behaviour have been documented in Kreher and Ruedebusch (UMTS Signaling. John Wiley & Sons, Ltd, 2005), which provides examples for technical experts investigating call flows and network procedures.
标签： Performance Measurement Practical Guide UMTS
上传时间： 2020-06-01
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Static electricity is the most ancient form of electricity known to humans. More than 2000 years ago, the Greeks recognized the attraction between certain mate- rials when they were rubbed together; indeed, the word electricity comes from the Greek elektron, which means amber. During the seventeenth and eighteenth centuries, several key experiments were conducted to understand and measure static electricity. But the discovery of electromagnetism and its formidable break- through has rapidly outgrown interest in static electricity. Even today, where the industrial applications of static electricity are not insignificant, they cannot compare with those of electromagnetism and electrodynamics.
标签： Understand Discharge Electro Static
上传时间： 2020-06-05
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Thanks to the advances in micromachining fabrication technologies and significant cost reduction due to mass production, miniature sensors of angular rate, or gyroscopes, found their way into the everyday life of every user of modern gadgets, such as smart phones, tablets or even wristwatches. Often without realising, many of us are carrying in our pockets fully equipped with all necessary sensors complete inertial navigation systems that not so long ago were available only for advanced vehicles in sea, land, air or space. Accelerometers and gyroscopes are found in specifications of any gadget supposed to react to user movements. And one of the most commonly used type of gyroscopes used to developed these systems is Coriolis vibratory gyroscope (CVG).
标签： Gyroscopes Vibratory Coriolis
上传时间： 2020-06-06
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A few years ago I stood before an audience at a customer’s facility explaining the merits of micromachining technology. The small conference room was packed, and all ears were attentive. Everyone was eager to learn about thismysteriousbuzzword, “MEMS.”Although many in the audience were nodding in a sign of comprehension, the glazed lookson their facesbetrayed them. Thisexperience isnot unique, but one that isrepeated frequently in auditoriumsaround the world.
上传时间： 2020-06-06
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There have been many developments in the field of power electronics since the publication of the second edition, almost five years ago. Devices have become bigger and better - bigger silicon die, and current and voltage ratings. However, semiconductor devices have also become smaller and better, integrated circuit devices, that is. And the marriage of low power integrated circuit tecnology and high power semiconductors has resulted in benefit to both fields.
标签： Electronics Handbook Edition Power
上传时间： 2020-06-07
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