Wireless Multimedia Communications - Hardcover

Wesel, Ellen Kayata

Hardcover

ISBN 10: 0201633949 ISBN 13: 9780201633948

Publisher: Addison-Wesley, 1997

Synopsis

This book is a comprehensive guide to understanding the design of wireless multimedia communications systems. Covering mobile video, voice, and data communications, it provides both professionals and students with an introduction to the problems and solutions of communicating multimedia traffic at high data rates over a radio channel for short distances. Wireless Multimedia Communications begins with an examination of the physical layer of the Open Systems Interface (OSI) stack, modeling the radio channel impairments, including path loss and multipath distortion. The book addresses infrared and satellite wireless channels and the digital modulation approaches used to convey information over these channels. It compares possible approaches to transmitting multimedia traffic, including equalization, multicarrier modulation, and spread spectrum. The book also presents an in-depth discussion of error control, with a look at the emerging and promising field of turbo coding. At the data link layer, the book presents an evaluation of Medium Access Control (MAC) protocols, such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), and Carrier Sense Multiple Access (CSMA) in terms of their performance in carrying multimedia traffic over wireless channels. A number of possible approaches for extending ATM technology to wireless networks is also explored. In addition, this book addresses infrared LANs, describing available devices, impairments and their solutions, and the current Infrared Data Association (IrDA) standard. A general overview of international standardization activities includes a description of the IEEE 802.11 standard, the U.S. data-PCS standard, and the European (HIPERLAN) standard. Ellen Kayata Wesel is a Senior Scientist at Hughes Communications, Inc. (HCI), where she designs next-generation systems that enable high data rate, multimedia traffic over wireless channels. Previously, she worked in Apple Computer's research laboratories, where she specialized in the design of wireless LANs. Dr. Wesel has taught short courses on wireless communications at UCSC Extension and at UCLA Extension.

About this title

About the Author

Ellen Kayata Wesel is a Senior Scientist at Hughes Communications, Inc. where she designs next-generation systems that enable high data rate, mulitmedia traffic over wireless channels. Previously, she worked in Apple Computer's research laboratories, where she specialized in the design of wireless LANs. Dr. Wesel has taught short courses on wireless communications at UCSC Extension and at UCLA Extension.

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From the Back Cover

Wireless Multimedia Communications begins with an examination of the physical layer of the Open Systems Interface (OSI) stack, modeling the radio channel impairments, including path loss and multipath distortion. The book addresses infrared and satellite wireless channels and the digital modulation approaches used to convey information over these channels. It compares possible approaches to transmitting multimedia traffic, including equalization, multicarrier modulation, and spread spectrum. The book also presents an in-depth discussion of error control, with a look at the emerging and promising field of turbo coding.

At the data link layer, the book presents an evaluation of Medium Access Control (MAC) protocols, such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), and Carrier Sense Multiple Access (CSMA) in terms of their performance in carrying multimedia traffic over wireless channels. A number of possible approaches for extending ATM technology to wireless networks is also explored.

In addition, this book addresses infrared LANs, describing available devices, impairments and their solutions, and the current Infrared Data Association (IrDA) standard. A general overview of international standardization activities includes a description of the IEEE 802.11 standard, the U.S. data-PCS standard, and the European (HIPERLAN) standard.

0201633949B04062001

From the Inside Flap

Wireless networks support mobility. They allow you instantaneous access to the files on your desktop, the library, and your friends while you walk about your office, college, or hospital campus, about the city, or into the park. At present, the most successful wireless network in existence, the cellular network, carries only voice traffic and some low data rate messaging, but its users value staying connected via a small, portable phone.

New applications have defined the need for high data rate systems carrying multimedia traffic. Users enjoying multimedia applications such as videoconferencing, advanced web browsing, and interactive games on their desktop computers want to extend that capability to mobile environments.

A global, ubiquitous wireless network will allow its users to communicate with anyone, anywhere, and at any time. As wireless networks become common, new applications will evolve to take full advantage of this liberating shift in the way we work and play.

Indoor coverage ranges of tens of meters will be required to satisfy the desire to remain in contact. High data rates (on the order of tens or hundreds of megabits per second) will be needed to carry your multimedia communications. In addition, these networks must carry a multimedia traffic mix of data, video, and voice packets, each of which has different transfer requirements. For example, data packets require a low bit error rate environment, but tolerate latency well, whereas voice traffic is robust with respect to errors, but is delay-sensitive. End users will expect their link through the radio network to be interactive and robust. Clearly, consumers demand that this wireless communicator be a small, low power, portable device.

This book is an introduction to the problems and solutions of communicating multimedia traffic for short distances at high data rates over a radio channel. It provides the broad technical background necessary to understand the issues in high-rate wireless digital communications design. It is intended for use by graduate students about to embark on researching wireless communications and by professional engineers and project managers involved in wireless systems design. This book focuses on explaining concepts and introduces mathematical derivations strictly to reveal details of the phenomenon or to allow application of the concept. This book is the distillation of hundreds of journal papers I have studied, of wireless systems I have designed, of discussions I have had with other researchers, and of standards meetings I have attended.

The research and design of wireless networks is truly a multidisciplinary endeavor. This book covers several traditionally separate topics. The reader who wishes to study a subtopic in more detail should explore the set of relevant references Iive included at the end of each chapter. Some books focusing on specific aspects of wireless have begun to emerge; Wireless Multimedia Communications integrates these different topics into one convenient reference.

In this book, we explore the building blocks of wireless multimedia systems. Chapter 1 introduces current wireless systems, most of which are voice-oriented, such as the cellular network, or carry data at under 19.2 kbps. Chapter 2 examines the physical layer of the Open Systems Interface (OSI) stack, modeling the radio channel impairments, including path loss and multipath. Multipath is the major impediment in sending high data rates over a radio channel, and refers to a transmitted radio signal taking several different paths to reach a receiver. Because these paths are of different lengths, and the radio signals all travel at the same speed, they arrive at different times at the receiver, effectively smearing the transmitted signal, and making it harder to decode. Chapter 3 introduces the digital modulation approaches used to convey information over these channels.

In order to transmit at the high data rates, we need to mitigate the radio channelis multipath effects. Chapters 4 and 5 compare the effectiveness of mitigating solutions, including equalization, multicarrier modulation, and spread spectrum. In order to reduce the channel error rate to levels acceptable for carrying data, the system needs to include error-correction techniques. Chapter 6 presents methods to correct and/or detect errors in the received bits. We explore block, convolutional, and turbo codes over fading channels.

Moving up the OSI stack to the data link layer, Chapter 7 compares Medium Access Control (MAC) protocols in terms of their performance in carrying multimedia traffic over wireless channels. Some of the analysis used for wired networks cannot be reused here, because of underlying assumptions that do not apply to the wireless domain. We provide an overview of network issues such as multihop, roaming, and routing. Asynchronous Transfer Mode (ATM) is becoming an important protocol over the wired backbone, and researchers are working on extending its services to the wireless link. Chapter 8 discusses some of the possible approaches to support wireless ATM.

Chapter 9 introduces infrared local area networks (LANs) as a short-range complementary solution to wireless radio networks. The radio spectrum is regulated by the Federal Communications Commission (FCC) in the U.S. and the International Telecommunications Union (ITU) internationally. These bodies impose regulations and standards for use of all nongovernment bands. Chapter 10 reviews current spectrum and international standardization activities for high data rate multimedia wireless networks. The Glossary offers a handy collection of commonly used acronyms.

The book says little on the topics of security and encryption, or health and safety issues, except to point out the latest studies on these topics. Several other books cover cellular technologies and standards; I do not repeat such information here.

I have used this material in short courses offered by the University of California extension programs. My audience at UCLA-Extension and UCSC-Extension primarily consists of professionals who wish, by choice or job requirement, to expand into the field of wireless communications. I believe the teaching approach is equally valid for a graduate course. The text is also useful as a reference book for practicing engineers. 0201633949P04062001

Edition details

• Publisher: Addison-Wesley
• Publication date: 1997
• Language: English
• ISBN 10: 0201633949
• ISBN 13: 9780201633948
• Binding: Hardcover
• Edition number: 1
• Number of pages: 298