Ultra-wideband (UWB) radios are expected to play a revolutionary role in the future of wireless communications systems. The great interest in UWB communications was sparked by FCC rulings in February 2002 that authorized the unlicensed commercial deployment of UWB technology under a strict power control in 7500 MHz of spectrum. This fast-emerging technology uses extremely narrow and low-power RF pulses to transmit and receive information. Using short-duration pulses as the basic building block of communication results in exceptionally attractive features as well as unique technical challenges.
This book provides a comprehensive introduction to UWB communications systems in a simple and easy-to-understand language. It covers the fundamentals of short pulse generation and propagation, regulatory issues, concerns about UWB interference, and UWB applications and potential target markets. The following items characterize the book.
Detailed discussion of the fundamentals of UWB technology, short-pulse generation, UWB antennas, UWB modulation and multiple-access techniques, as well as UWB applications.
Comparative analysis of UWB, narrowband, and spread-spectrum wideband communication systems, emphasizing the strengths and weaknesses of UWB technology compared to traditional continuous-wave wireless communications techniques.
Full description of the interference issues relating to the coexistence of UWB systems with narrowband and wideband spread-spectrum communications systems, such as IEEE 802.11a/b wireless local area networks (WLANs), the Global Positioning System (GPS), and cellular phones.
Coverage of FCC regulations for UWB communications systems in the United States, as well as worldwide regulatory efforts.
Identification of UWB's potential target markets, such as military, entertainment, and automotive industries, including comprehensive market research and analysis on this promising technology.
Comprehensive bibliographies at the end of each chapter to help readers delve further into the concepts discussed in the book.
A concise glossary of all technical terms used throughout the book, which enables readers with minimal or no background in RF principles to benefit from this book.
Ultra-Wideband Communications is written for a broad range of readers. The simple language and full coverage of the technology makes this book a complete reference for individuals new to the field of UWB communications and for nontechnical readers, as well as a good study aid for undergraduate students so that they can better understand more technical textbooks. In addition, managers, marketers, analysts, purchasing agents, journalists, continuing education students, and engineers new to the field can all benefit from reading this book.
The book is organized in the following fashion:
Chapter 1 provides a comprehensive overview of UWB communications by covering its history and background. We discuss the concepts behind UWB communications as well as UWB's advantages and challenges. In this chapter, we explain in great detail the difference between UWB and spread-spectrum communications, and we examine the strengths and weaknesses of UWB compared to narrowband and spread-spectrum wideband communications. Chapter 1 covers the single-band and multiband approaches that are the two leading UWB techniques under consideration for IEEE standardization. This chapter also addresses current FCC and worldwide regulatory efforts for the commercialization of UWB. Finally, the chapter concludes with a brief discussion of UWB applications.
Chapter 2 concentrates on UWB pulse-generation techniques. In simple language, we introduce the concepts of pulse generation using step recovery diodes (SRDs) and drift step recovery diodes (DSRDs), as well as pulse shaping techniques. The chapter also presents a detailed discussion of UWB antenna concepts, including system and network considerations.
Chapter 3 focuses on the advantages and disadvantages of several modulation/demodulation schemes used for UWB pulse detection. The modulation techniques covered are on-off keying (OOK), pulse-amplitude modulation (PAM), pulse-position modulation (PPM), bi-phase modulation, and transmitted-reference (TR) modulation. The chapter also discusses the concepts behind energy detectors and classical matched filters (CMF), which are the basis for most pulse-detection techniques. Chapter 3 further explains UWB multiple-access techniques based on each modulation technique, as well as time-hopping and delay-hopping concepts to avoid catastrophic collisions in multiuser channels.
Chapter 4 examines the interference issues of UWB systems to existing narrowband and wideband radio services. Specific cases of UWB interference to IEEE 802.11a/b WLANs, GPS, and cellular phones are discussed thoroughly in terms of the UWB transmitter density that can degrade the performance of each radio service to a harmful level.
Chapter 5 provides a detailed and quantitative look at some key UWB applications of widespread interest in the entertainment, military and government, as well as automotive, industries. This chapter identifies the initial, existing, and future target markets for UWB in the commercial sector and offers a full market analysis in terms of UWB speed-to-market advantages, the technology's adaptation timeline, as well as market projections and forecasts for UWB products up to the year 2010.
Appendix A adds an in-depth theoretical analysis of UWB interference issues on WLAN, GPS, and cellular systems to complement the discussion in Chapter 4, especially for readers interested in theoretical derivations of formulas used for interference analysis.