The first question most readers of an O’Reilly book might ask is about the choice of the cover animal. In this case, “why a duck?” Well, for the record, our first choice was a unicorn decked out in glitter and a rainbow sash. That response always gets a laugh (we are sure you just giggled a little), but it also brings to the surface a common perception of software-defined networks among many expe‐ rienced network professionals. Although we think there is some truth to this perception, there is certainly more meat than myth to this unicorn.
標(biāo)簽： Networks Software Defined SDN
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
This book was born from the perception that there is much more to spectrum use and sharing than one sees reflected in publications, whether academic, commercial or political. the former – in good research style – tend towards reductionism and concentrate on specific, detailed aspects. commercial publications tend to empha- size the positive aspects and they tend to put promise above practice. Given the ever increasing pace of technology development and recent successes of new wireless technologies, some pundits predict large-scale spectrum scarcity, potentially lead- ing to economic catastrophe. Although economic theory has a hard time explaining recent events that shook the world economy, the notion of spectrum scarcity is intui- tively acceptable, even if not correct or immediately relevant.
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
Ultra-wideband (UWB) technology enables high data-rate short-range communica- tion, in excess of hundredmegabit-per-secondsand up to multi-gigabit-per-seconds, over a wide spectrum of frequencies, while keeping power consumption at low lev- els. This low power operation results in a less-interfering co-existence with other existed communication technologies (e.g., UNII bands). In addition to carrying a huge amount of data over a distance of up to 230 feet at very low power (less than 0.5mW), the UWB signal has the ability to penetrate through the doors and other obstacles that tend to reflect signals at more limited bandwidths and higher power densities.
標(biāo)簽： Silicon-Based Front-Ends RF
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
Since the first edition of the book was published, the field of modeling and simulation of communication systems has grown and matured in many ways, and the use of simulation as a day-to-day tool is now even more common practice. Many new modeling and simulation approaches have been developed in the recent years, many more commercial simulation packages are available, and the evolution of powerful general mathematical applications packages has provided still more options for computer-aided design and analysis. With the current interest in digital mobile communications, a primary area of application of modeling and simulation is now to wireless systems of a different flavor than the traditional ones.
標(biāo)簽： Communication Simulation Systems of
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
Spread-spectrum communication is a core area within the field of digital communication. Originally used in military networks as countermeasures against the threats of jamming and interception, spread-spectrum systems are now widely used in commercial applications and are part of several wireless and mobile communication standards. Although spread-spectrum communication is a staple topic in textbooks on digital communication, its treatment is usually cursory. This book is designed to provide a more intensive examination of the subject that is suitable for graduate students and practicing engineers with a solid background in the theory of digital communication. As the title indicates, this book stresses principles rather than specific current or planned systems, which are described in manyotherbooks.My goal in this bookis to providea concisebut lucidexplanation of the fundamentals of spread-spectrum systems with an emphasis on theoretical principles.
標(biāo)簽： Spread-Spectrum Communication Systems 2nd
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
The serious study of the practice of how to determine the appropriate content of a specification is a seldom-appreciated pastime. Those who have the responsibility to design a product would prefer a greater degree of freedom than permitted by the con- tent of a specification. Many of those who would manage those who would design a product would prefer to allocate all of the project funding and schedule to what they consider more productive labor. These are the attitudes, of course, that doom a project to defeat but they are hard to counter no matter how many times repeated by design engineers and managers. A system engineer who has survived a few of these experiences over a long career may retire and forget the past but we have an endur- ing obligation to work toward changing these attitudes while trying to offer younger system engineers a pathway toward a more sure success in requirements analysis and specification publishing.
標(biāo)簽： Requirements Analysis System
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
In this book we focus on the basic signal processing that underlies current and future ultra wideband systems. By looking at signal processing in this way we hope this text will be useful even as UWB applications mature and change or regulations regarding ultra wideband systems are modified. The current UWB field is extremely dynamic, with new techniques and ideas being presented at every communications and signal-processing conference. The basic signal-processing techniques presented in this text though will not change for some time to come. Thus, we have taken a somewhat theoretical approach, which we believe is longer lasting and more useful to the reader in the long term than an up-to-the-minute summary that is out of date as soon as it is published.
標(biāo)簽： Wideband Signals Systems Ultra 1st
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
The continuing explosive growth in mobile communication is demanding more spectrally efficient radio access technologies than the prevalent second generation (2G) systems such as GSM to handle just the voice traffic. We are already witnessing high levels of mobile penetration exceeding 70% in some countries. It is anticipated that by 2010 more than half of all communications will be carried out by mobile cellular networks. On the other hand, the information revolution and changing life habits are bringing the requirement of commu- nicating on a multimedia level to the mobile environment. But the data handling capabilities and flexibility of the 2G cellular systems are limited.
標(biāo)簽： Planning Network UMTS
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
Welcome to the world of wireless communications and the logical extension to the broadband architectures that are emerging as the future of the industry. No aspect of communications will be untouched by the wireless interfaces;no part of our working environment will be left untouched either. As the world changes and the newer technologies emerge, we can expect to see more in the line of untethered communications than in the wired inter- faces.
標(biāo)簽： Broadband Wireless Handbook
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
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.
標(biāo)簽： Understand Discharge Electro Static
上傳時(shí)間： 2020-06-05
上傳用戶：shancjb
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