Two of the major developments reshaping the telecommunications landscape are mobile wireless connectivity and the migration of voice telephone services to IP technology. Those two ideas come together in networks that carry voice services over a wireless LAN (VoWLAN). The purpose of this text is to provide network professionals with the technical background and practical guidance needed to deploy These networks successfully.
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Wavelength division multiplexing (WDM) refers to a multiplexing and transmission scheme in optical telecommunications fibers where different wavelengths, typically emitted by several lasers, are modulated independently (i.e., they carry independent information from the transmitters to the receivers). These wavelengths are then multiplexed in the transmitter by means of passive WDM filters, and likewise they are separated or demultiplexed in the receiver by means of the same filters or coherent detection that usually involves a tunable local oscillator (laser).
標簽： Multiplexing Wavelength Division
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The use of optical free-space emissions to provide indoor wireless commu- nications has been studied extensively since the pioneering work of Gfeller and Bapst in 1979 [1]. These studies have been invariably interdisciplinary in- volving such far flung areas such as optics design? indoor propagation studies? electronics design? communications systems design among others. The focus of this text is on the design of communications systems for indoor wireless optical channels. Signalling techniques developed for wired fibre optic net- works are seldom efficient since they do not consider the bandwidth restricted nature of the wireless optical channel.
標簽： Communication Wireless Optical Systems
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The advent of modern wireless devices, such as smart phones and MID 1 terminals, has revolutionized the way people think of personal connectivity. Such devices encompass multiple applications ranging from voice and video to high-speed data transfer via wireless networks. The voracious appetite of twenty-first century users for supporting more wireless applications on a single device is ever increasing. These devices employ multiple radios and modems that cover multiple frequency bands and multiple standards with a manifold of wireless applications often running simultaneously.
標簽： Architectures Wireless Receiver Design and
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A wireless ad-hoc network is a wireless network deployed without any infrastructure. In such a network, there is no access point or wireless router to forward messages among the computing devices. Instead, These devices depend on the ad-hoc mode of their wireless net‐ work interface cards to communicate with each other. If the nodes are within the transmis‐ sion range of the wireless signal, they can send messages to each other directly. Otherwise, the nodes in between will forward the messages for them. Thus, each node is both an end system and a router simultaneously.
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Mobile radio communications are evolving from pure telephony systems to multimedia platforms offering a variety of services ranging from simple file transfers and audio and video streaming, to interactive applications and positioning tasks. Naturally, These services have different constraints concerning data rate, delay, and reliability (quality-of-service (QoS)). Hence, future mobile radio systems have to provide a large flexibility and scal- ability to match These heterogeneous requirements.
標簽： Communications Wireless Channels MIMO over
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This chapter provides extensive coverage of existing mobile wireless technologies. Much of the emphasis is on the highly anticipated 3G cellular networks and widely deployed wireless local area networks (LANs), as the next-generation smart phones are likely to offer at least These two types of connectivity. Other wireless technologies that either have already been commercialized or are undergoing active research and standardization are introduced as well. Because standardization plays a crucial role in developing a new technology and a market, throughout the discussion standards organizations and industry forums or consortiums of some technologies are introduced. In addition, the last section of this chapter presents a list of standards in the wireless arena.
標簽： Networking Wireless Complete
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Welcome to the third volume of the book entitled Technologies for the Wireless Future, which is produced by WWRF. The idea is to take the most important outputs from the working groups and special-interest groups that compose the Forum and bring them together in a series of one-volume surveys. The latest of These will give the reader a good overview of the WWRF approach to analyzing the future of wireless and mobile communications, as well as an insight into the trends themselves and the key technologies that will be deployed.
標簽： Wireless Research Forum World
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This effort started as an answer to the numerous questions the authors have repeatedly had to answer about electrostatic discharge (ESD) protection and input/output (1/0) designs. In the past no comprehensive book existed suffi- ciently covering These areas, and These topics were rarely taught in engineering schools. Thus first-time I/O and ESD protection designers have had consider- able trouble getting started. This book is in part an answer to such needs.
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As we enter the next millennium, there are clear technological patterns. First, the electronic industry continues to scale microelectronic structures to achieve faster devices, new devices, or more per unit area. Secondly, electrostatic charge, electrostatic discharge (ESD), electrical overstress (EOS) and electromagnetic emissions (EMI) continue to be a threat to These scaled structures. This dichotomy presents a dilemma for the scaling of semiconductor technologies and a future threat to new technologies. Technological advancements, material changes, design techniques, and simulation can fend off this growing concern – but to maintain this ever-threatening challenge, one must continue to establish research and education in this issue.
標簽： ESD-Phenomena-and-the-Reliability
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