An Introduction to Ultra Wideband Communication Systems

1.5. Overview of the Book

This book is designed to be an interdisciplinary study of UWB communication systems. The development of channel models for UWB communication systems requires extensive data on propagation of UWB signals. Both experimental and simulation techniques can be used to examine the propagation of UWB signals in indoor and indoor/outdoor environments. In Chapter 2, "Channel Measurement and Simulation," time domain and frequency domain measurement methods for UWB channel sounding and their advantages and disadvantages are discussed. The electromagnetic simulation of UWB signal propagation in indoor environments is also addressed in Chapter 2. In Chapter 3, channel models and UWB link budgets are developed based on data collected from extensive UWB propagation measurements.

A critical component of UWB propagation, the antenna, is covered in Chapter 4. This chapter presents a detailed parametric study of time and frequency domain characteristics of both the antenna and scattering structures that must be considered in the performance estimates of UWB links. Additionally, mathematical modeling is presented that allows the antenna effects to be theoretically integrated into the UWB channel models.

As discussed previously in this chapter, transmitter and receiver design presents a unique challenge for UWB systems, particularly with the emphasis on low power, low cost devices. Chapter 5, "Transmitter Design," describes several widely used signal generation and modulation/signaling schemes unique to both I-UWB and MC-UWB. Chapter 6 provides a comprehensive review of a wide variety of UWB receiver architectures, with an emphasis on different mechanisms for optimally demodulating the received UWB signal.

UWB signals will encounter interference from many sources, primarily from relatively narrowband systems. In addition, UWB signals will also affect a large number of narrowband radios; of critical importance is the potential interference with GPS, E-911, and navigation bands. In Chapter 7, we assess, via analysis and simulations, the interference caused by UWB signals, as well as the impact of narrowband interference on a UWB receiver.

Simulation of UWB communication systems is unique in that it emphasizes the transient nature of UWB systems, and it is the focus of Chapter 8, "Simulation." This chapter covers several subjects important to efficient and accurate simulation of UWB communication systems, including challenges introduced by the simulation of UWB, architectural approaches to simulating UWB communication systems, and simulation models for UWB communication systems components.

Chapter 9, "Networking," addresses networking issues for networks of directly connected UWB nodes and larger ad hoc networks where network formation and multihop routing is required. In Chapter 9, we will examine several design issues related to UWB networks, including data link layer design, architectures of multihop ad hoc networks, and corresponding routing schemes, as well as related issues such as performance and Quality of Service (QoS) management.

Chapter 10, "Applications and Case Studies," explores the wide range of applications that can exploit the unique properties of I-UWB. Practical examples will be discussed from among some of the first commercial UWB products that feature several of the diverse set of UWB applications, including precision location, radar, imaging, distributed sensors, and high-speed communication. Appendix A of Chapter 10 provides a brief overview of the IEEE 802.15.3a preliminary standard that describes the MAC and PHY layers^[6] of a wireless personal area network (WPAN).

^[6] At the time of publication, the PHY layer has not been fully determined; two alternative candidates remain.