Author: Gene Wesley Marsh
Publisher:
ISBN:
Category : Infrared detectors
Languages : en
Pages : 234

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Book Description

Author: John R. Barry
Publisher: Springer Science & Business Media
ISBN: 1461527007
Category : Technology & Engineering
Languages : en
Pages : 186

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Book Description
The demand for wireless access to network services is growing in virtually all communications and computing applications. Once accustomed to unteathered opera tion, users resent being tied to a desk or a fixed location, but will endure it when there is some substantial benefit, such as higher resolution or bandwidth. Recent technolog ical advances, however, such as the scaling of VLSI, the development of low-power circuit design techniques and architectures, increasing battery energy capacity, and advanced displays, are rapidly improving the capabilities of wireless devices. Many of the technological advances contributing to this revolution pertain to the wireless medium itself. There are two viable media: radio and optical. In radio, spread-spectrum techniques allow different users and services to coexist in the same bandwidth, and new microwave frequencies with plentiful bandwidth become viable as the speed of the supporting low-cost electronics increases. Radio has the advantage of being available ubiquitously indoors and outdoors, with the possibility of a seam less system infrastructure that allows users to move between the two. There are unan swered (but likely to be benign) biological effects of microwave radiation at higher power densities. Optical communications is enhanced by advances in photonic devices, such as semiconductor lasers and detectors. Optical is primarily an indoor technology - where it need not compete with sunlight - and offers advantages such as the immediate availability of a broad bandwidth without the need for regulatory approval.

Author: Andrew Pengfei Tang
Publisher:
ISBN:
Category :
Languages : en
Pages : 104

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Book Description

Author: Mohammad Reza Pakravan
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
The emergence of portable computing devices is expected to accelerate the introduction of wireless Local Area Networks (LANs). Portable devices require connectivity with low power consumption, small size and weight. The demand for inexpensive, high-speed communication links satisfying these requirements his encouraged the research on infrared wireless communications. In this thesis, the fundamentals of infrared communications and different suitable configurations are reviewed. The basic nature of the infrared channel, the differences between the infrared channel and radio frequency channel and the important communication problems faced by infrared systems are explained. An infrared channel simulation algorithm that is used to estimate its impulse response is described. An extensive set of measurements has been performed to investigate the effects of receiver rotation, receiver shadowing, receiver displacement, transmission configuration and communications environments on the characteristics of the infrared channel. The characteristics of the wide-band measurement system that was used to collect the infrared channel transfer functions are presented. The objectives, procedures, results and conclusions of these measurements are discussed and reported. Diffusers are an important element of infrared transmission systems. They are used to control the radiation pattern of the transmitter for efficiency and eye-safety. Holographic diffusers have been designed and manufactured to provide better infrared radiation patterns. These diffusers were used in the measurement setup to assess the performance enhancements that can be achieved by using holographic diffusers. The results show uniform and efficient use of optical power and better tolerance to shadowing by using these devices.

Author: Rob Otte
Publisher: Springer Science & Business Media
ISBN: 1475730152
Category : Technology & Engineering
Languages : en
Pages : 159

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Book Description
Today, wireless infrared transmission has entered our homes, offices, industry and health care, with applications in the field of remote control, telemetry, and local communication. This book is about the underlying technology. As it is an outgrowth of my Ph.D. thesis, the emphasis is on fundamental aspects rather than industrial aspects, like the standardization effort by the IrDA [7]. I guess that this is not a drawback, as, eventually, the laws of physics apply to all of us! As the applied radiation is not necessarily in the infrared, throughout the book we usually prefer the term optical transmission. As most equipment is battery-powered, the emphasis is on power optimiza tion of the optical transmission system. System parameters as well as environ mental parameters that determine the eventual transmission quality are iden tified, to facilitate well-reasoned system design. Many design rules, based on calculations, measurements and simulations are presented to help the designer push the performance close to the limits set by nature and the available tech nology. The first chapters introduce the subject and the present the scope of the book. Then, the basic transmission link is introduced in chapter 3, and strate gies to optimize its signal-to-noise ratio are discussed. Lighting flicker is identi fied as a possible source of interference. Then, receiver noise and bandwidth are discussed in chapter 4, mainly based on the material presented in [66], [67], [69].

Author: Emmanuel Baleke Zyambo
Publisher:
ISBN:
Category : Telecommunication networks and computer systems
Languages : en
Pages : 0

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Book Description

Author: Roberto Ramirez-Iniguez
Publisher: CRC Press
ISBN: 1000654524
Category : Technology & Engineering
Languages : en
Pages : 294

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Book Description
Over the last three decades, interest in Infrared (IR) technology as a medium to convey information has grown considerably. This is reflected by the increasing number of devices such as laptops, PDAs, and mobile phones that incorporate optical wireless transceivers and also by the increasing number of optical wireless links available for indoor and

Author: Steve Hranilovic
Publisher: Springer Science & Business Media
ISBN: 0387227857
Category : Technology & Engineering
Languages : en
Pages : 197

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Book Description
This volume addresses the problem of designing efficient signalling and provides a link between the areas of communication theory and modem design for amplitude constrained linear optical intensity channel. It provides practical guidelines for the design of signalling sets for wireless optical intensity channels.

Author: Jack M. Holtzman
Publisher: Springer Science & Business Media
ISBN: 1461531446
Category : Technology & Engineering
Languages : en
Pages : 346

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Book Description
The past several years have been exciting for wireless communications. The public appetite for new services and equipment continues to grow. The Second Generation systems that have absorbed our attention during recent years will soon be commercial realities. In addition to these standard systems, we see an explosion of technical alternatives for meeting the demand for wireless communications. The debates about competing solutions to the same problem are a sign of the scientific and technical immaturity of our field. Here we have an application in search of technology rather than the reverse. This is a rare event in the information business. Happily, there is a growing awareness that we can act now to prevent the technology shortage from becoming more acute at the end of this decade. By then, market size and user expectations will surpass the capabilities of today's emerging systems. Third Generation Wireless Information Networks will place even greater burdens on technology than their ancestors. To discuss these issues, Rutgers University WINLAB plays host to a series of Workshops on Third Generation Wireless Information Networks. The first one, in 1989, had the flavor of a gathering of committed enthusiasts of an interesting niche of telephony. Presentations and discussions centered on the problems of existing cellular systems and technical alternatives to alleviating them. Although the more distant future was the announced theme of the Workshop, it drew only a fraction of our attention.

Author: Ke Wang
Publisher: CRC Press
ISBN: 1000765555
Category : Technology & Engineering
Languages : en
Pages : 201

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Book Description
This book aims to give an overview of recent developments in indoor near-infrared optical wireless communication technologies and systems, including basic theories, operating fundamentals, system architectures, modelling, experimental demonstrations, advanced techniques, and most recently, the research efforts towards integrations. Both line-of-sight and diffusive-signals-based options will be reviewed, to provide readers a complete picture about this rapidly developing area, which targets the provision of high-speed wireless connectivity to end- users in indoor environments, such as offices, homes and shopping centres, to satisfy the growing high-speed communication requirement. Provides a systematic approach for the fundamentals of indoor optical wireless communications. Provides an overview of recent developments in indoor infrared optical wireless communications, including theoretical fundamentals. Examines system architectures, modelling, experimental demonstrations, and the research efforts towards integrations. Dr. Ke Wang is an Australian Research Council (ARC) DECRA Fellow and a senior lecturer in the School of Engineering, Royal Melbourne Institute of Technology (RMIT University), VIC, Australia. He worked with the University of Melbourne, Australia, and Stanford University, California, before joining RMIT University. He has published over 110 peer-reviewed papers in top journals and leading international conferences, including over 20 invited papers. He has been awarded several prestigious national and international awards as recognition of research contributions, such as the Victoria Fellowship, the AIPS Young Tall Poppy Science Award, and the Marconi Society Paul Baran Young Scholar Award. His major areas of interest include: silicon photonics integration, opto-electronics integrated devices and circuits, nanophotonics, optical wireless technology for short-range applications, quasi-passive reconfigurable devices and applications and optical interconnects in data -centres and high-performance computing.