This book is exclusively dedicated to WiMAX. The focus of the book is
on the applications of WiMAX networks, with delivery of multimedia
content to wireless and mobile devices being the Area of greatest atten-
tion. WiMAX has crossed a number of major milestones in the recent
past.
With this book at your fingertips, you, the reader, and I have something in common. We share
the same interest in mobile radio channels. This Area attracted my interest first in autumn 1992
whenImovedfromindustrytoacademiatofindachallengeinmylifeandtopursueascientific
career. Since then, I consider myself as a student of the mobile radio channel who lives for
modelling, analyzing, and simulating them. While the first edition of this book resulted from
my teaching and research activities at the Technical University of Hamburg-Harburg (TUHH),
Germany, the present second edition is entirely an outcome of my work at the University of
Agder, Norway.
Wireless metropolitan Area networks (WirelessMANs) is emerging as a promising
broadband wireless access (BWA) technology to provide high-speed, high bandwidth
efficiency and high-capacity multimedia services for residential as well as enterprise
applications. It is observed that WirelessMAN (e.g., WiMAX) is even regarded as a 4G
technology. For the success of the WirelessMANs, international standardization organiza-
tions are very actively specifying the standards IEEE 802.16, ETSI HiperMAN and Korea
WiBro.
At the macroscopic level of system layout, the most important issue is path loss. In the
older mobile radio systems that are limited by receiver noise, path loss determines SNR and
the maximum coverage Area. In cellular systems, where the limiting factor is cochannel
interference, path loss determines the degree to which transmitters in different cells interfere
with each other, and therefore the minimum separation before channels can be reused.
In recent years, the research and developments in the Area of RF and microwave
technologies have progressed significantly due to the growing demand for applica-
bility in wireless communication technologies. Starting from 1992, wireless com-
munication technologies have become quite mature. In the modern era of electronic
developments, design of wireless handsets is an example of integration of many di-
verse skill sets. Classical books in the Areas of microwave technology provide us
with an in-depth knowledge of electromagnetic fundamentals.
Notwithstanding its infancy, wireless mesh networking (WMN) is a hot and
growing field. Wireless mesh networks began in the military, but have since
become of great interest for commercial use in the last decade, both in local
Area networks and metropolitan Area networks. The attractiveness of mesh
networks comes from their ability to interconnect either mobile or fixed
devices with radio interfaces, to share information dynamically, or simply to
extend range through multi-hopping.
Mobile wireless communications are in constant evolution due to the continu-
ously increasing requirements and expectations of both users and operators.
Mass multimedia* services have been for a long time expected to generate a large
amount of data traffic in future wireless networks [1]. Mass multimedia services
are, by definition, purposed for many people. In general, it can be distinguished
between the distribution of any popular content over a wide Area and the distribu-
tion of location-dependent information in highly populated Areas. Representative
examples include the delivery of live video streaming content (like sports compe-
titions, concerts, or news) and file download (multimedia clips, digital newspa-
pers, or software updates).
Optical wireless communication is an emerging and dynamic research and development
Area that has generated a vast number of interesting solutions to very complicated
communication challenges. For example, high data rate, high capacity and minimum
interference links for short-range communication for inter-building communication,
computer-to-computer communication, or sensor networks. At the opposite extreme is
a long-range link in the order of millions of kilometers in the new mission to Mars
and other solar system planets.
The roots of this book were planted about a decade ago. At that time, I became
increasingly convinced that wide-Area and metropolitan-Area networks, where much
of my group’s research has been centered at that time, were in good shape. Although
research in these fields was (and still is) needed, that’s not where the networking
bottleneck seemed to be. Rather, the bottleneck was (and still is in many places) in
the access networks, which choked users’ access to information and services. It was
clear to me that the long-term solution to that problem has to involve optical fiber
access networks.
