xiv PREFACE
The introduction to this book presents a brief look at why UWB is considered to
be such an exciting wireless technology for the near future. We examine Shannon’s
famous capacity equation and, as a consequence, look at the large-bandwidth
possibilities for high data rate communication.
Chapter 1 presents the basic properties of UWB. We examine the power spectral
density, basic pulse shape, and spectral shape of these pulses. The regulatory
requirements laid down by the FCC are briefly described. Why UWB is considered
to be a multipath-resistant form is also examined, and such basic features of merit
such as capacity and speed of data transmission are considered. We finish the
chapter with a look at the cost, size, and power consumption that is forecast for
UWB devices and chipsets.
Chapter 2 examines in detail how to generate pulse waveforms for UWB sys-
tems, for both simple cases, such as the Gaussian pulse shape, and more complex
orthogonal pulses. We examine the possibility of designing pulses to fit spectral
masks, such as mandated by regulators, or to avoid interference with other fre-
quency bands. We finish the chapter with a look at some practical constraints and
the effects of imperfections on these designer pulse shapes.
Chapter 3 looks at different signal-processing techniques for UWB systems. The
chapter begins with a review of basic signal-processing techniques, including both
time and frequency domain techniques. The Laplace, Fourier, and z-transforms
are reviewed and their application to UWB is discussed. Finally, some practical
issues, such as pulse detection and amplification, are discussed.
The wireless indoor channel and how it should be modeled for UWB commu-
nications is considered in Chapter 4. Following our basic pattern we define and
explore the basic concepts of wideband channel modeling and show a simplified
UWB multipath channel model that is amenable to both theoretical analysis and
simulation. Path loss effects and a two-ray model are presented. Finally, the
frequency domain autoregressive model is discussed.
Chapter 5 takes a look at some of the fundamental communication concepts
and how they should be applied to UWB. First, modulation methods applicable
to UWB are presented. A basic communication system consisting of transmitter,
receiver, and channel is discussed. Since most consumer communication systems
do not consist of only one user, multiple access techniques are introduced. The
simple capacity of a UWB system is derived. Since other wireless consumer com-
munication systems have already become popular, a comparison between UWB
and other wideband techniques is included. Finally, the chapter ends with a look
at interference to and from UWB systems.
Chapter 6 is concerned with ultra wideband antennas and arrays of antennas.
This is considered one of the most difficult problems that must be overcome before
the widespread commercialization of UWB devices takes place. Antenna funda-
mentals are first introduced, including Maxwell’s equations for free space, antenna
field regions, directivity, and gain. The suitability of conventional antennas for
UWB transmission and reception is discussed in detail. More suitable impulse