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Ugweje WL040/Bidgolio-Vol I WL040-Sample.cls June 19, 2003 17:10 Char Count= 0
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Radio Frequency and Wireless
Communications
Radio Frequency and Wireless
Communications
Okechukwu C. Ugweje,The University of AkronIntroduction 177
Overview of RF Wireless Communication 177
Introduction 177
System Architecture 178
Radio Spectrum Classification 179
Radio Wave Characteristics 179
Forms of Radio Waves 180
Radio-Frequency-Based Systems 181
Radio Wave Propagation 183
Free Space Propagation 183
Reflection 183
Refraction 184
Diffraction 184
Scattering 184
Interference 184
Absorption 185
Doppler Effect 185
Path Loss 185
Shadowing 185Multipath Fading 185
Wireless Communication Techniques 186
Spread Spectrum 186
Diversity 186
Multiple Access 187
Cellular Communication 187
Cells 187
Clusters 188
Frequency Reuse 188
Interference 188
Cell Splitting 188
Cell Sectoring 188
Handoff 188
Emerging RF Wireless Technologies 188
Concluding Remarks 189
Glossary 189
Cross References 190
References 190INTRODUCTION
Radio-frequency (RF) wireless communication systems
have been around for many years with applications rang-
ing from garage door openers to satellite communication.
The technology has been advancing at an unprecedented
rate and its impact is evident in our daily lives. In many
parts of the world, wireless communication is the fastest
growing area of the communication industry, providing
a valuable supplement and alternative to existing wired
networks (Cellular Communications Services in the USA,
2003). Based on the number of subscribers to wireless
communication products and services, it is now the pre-
ferred method of communication (Wireless Communica-
tions, Market & Opportunities, 2003). Many systems for-
merly carried over the wire are now carried over wireless
media.
The remarkable success of cellular mobile radio tech-
nology has fundamentally changed the way people com-
municate and conduct business. The wireless revolution
has led to a new multi-billion-dollar wireless communi-
cations industry. Linking service areas, wireless commu-
nication has altered the way business is conducted. For
example, with a laptop computer, a wireless modem, and
a cellular phone, a business consultant can contact his
or her office and clients and conduct business while trav-
eling. While traveling, field service and sales personnelcan access corporate databases to check inventory sta-
tus, prepare up-to-the-minute price and delivery quotes,
modify schedule activities, and fulfill orders directly to the
factory. Company personnel can use two-way paging ser-
vices to stay in close contact, even when traditional wired
communication services are available. Handheld hybrid
phone-computer-fax machines feed information to wire-
less communication networks, allowing an executive to
make decisions while on a leisure outing.
In this chapter, we present a concise summary of the
subject of RF and wireless communication. This includes
a discussion of the general concepts and definitions of RF
wireless communication, various forms and applications
of RF wireless communication, and the concepts, prop-
erties, and behavior of radio waves. We also summarize
existing and emerging technologies for wireless commu-
nication. Of particular interest is the cellular mobile radio
system, which has become the most widespread RF wire-
less communication system.OVERVIEW OF RF WIRELESS
COMMUNICATION
Introduction
Wireless or RF communication began at the turn of
the 20th century, over 100 years ago, when Marconi177