The past two decades have witnessed the introduction and unprecedented growth of cellular
mobile telephony and wireless communications. Numerous wireless access technologies
have been introduced in the mobile communications market. While some have flourished
and formed the Basis of successful manufacturing and network operator businesses, many
have lived only for a short time and disappeared.
This thesis is about wireless communication in shared radio spectrum. Its origin and
motivation is ideally represented by the two quotations from above. In this thesis, the
support of Quality-of-Service (QoS) in cognitive radio networks is analyzed. New
approaches to distributed coordination of cognitive radios are developed in different
spectrum sharing scenarios. The Wireless Local Area Network (WLAN) 802.11 proto-
col of the Institute of Electrical and Electronics Engineers (IEEE) (IEEE, 2003) with
its enhancement for QoS support (IEEE, 2005d) is taken as Basis. The Medium Access
Control (MAC) of 801.11(e) is modified to realize flexible and dynamic spectrum
assignment within a liberalized regulation framework.
A series of features makes the mobile telecommunications industry an
interesting field of investigation for economists: the industry is experi-
encing veryfastmarketgrowthcombinedwithrapidtechnological change;
regulatory design in setting market structure is playing a very important
role; and oligopolistic competition is unfolding under various forms. The
number of subscribers to mobile networks is growing at a rapid rate on a
worldwide Basis, as shown in figure 1.1.
Wireless is one of the most rapidly developing technologies in our time, with dazzling
new products and services emerging on an almost daily Basis. These developments present
enormous challenges for communications engineers, as the demand for increased wireless
capacity grows explosively. Indeed, the discipline of wireless communications presents
many challenges to designers that arise as a result of the demanding nature of the physical
medium and the complexities in the dynamics of the underlying network.
Never have telecommunications operations and network management been so
important. Never has it been more important to move away from practices that date
back to the very beginning of the telecommunications industry. Building and con-
necting systems internally at low cost, on an as - needed Basis, and adding software
for supporting new networks and services without an overall architectural design
will not be cost effective for the future. Defi ning operations and network manage-
ment requirements at the 11th hour for new technologies, networks, and services
deployments must also change.
Communication protocols – for short protocols – form the Basis for the opera-
tion of computer networks and telecommunication systems. They are behavior
conventions which describe how communication systems interact with each other
in computer networks. Protocols define the temporal order of the interactions and
the formats of the data units exchanged. Communication protocols comprise a
wide range of different functions and mechanisms, such as the sending and receiv-
ing of data units, their coding/decoding, error control mechanisms, timer control,
flow control, and many others.
Telecommunications is today widely understood to mean the electrical means of
communicating over a distance. The first form of telecommunications was that of
the Telegraph, which was invented quite independently in 1837 by two scientists,
Wheatstone and Morse. Telegraphy was on a point-to-point unidirectional Basis and
relied on trained operators to interpret between the spoken or written word and the
special signals sent over the telegraph wire. However, the use of telegraphy did
greatly enhance the operations of railways and, of course, the dissemination of news
and personal messages between towns.
The goal of this book is to introduce the simulation methods necessary to describe
the behaviour of semiconductor devices during an electrostatic discharge (ESD).
The challenge of this task is the correct description of semiconductor devices under
very high current density and high temperature transients. As it stands, the book
can be no more than a snapshot and a summary of the research in this field
during the past few years. The authors hope that the book will provide the Basis
for further development of simulation methods at this current frontier of device
physics.
Although doing science is at the heart of discovery, the effort would have
very limited consequence in the long term without writingscience. As a social
enterprise that depends on collaboration, scientific inquiry requires its practi-
tioners to write on a regular Basis. From time to time, some members of the
scientific community have been critical of the overall quality of writing by re-
searchers.
The chief objective of Electric Machinery continues to be to build a strong
foundation in the basic principles of electromechanics and electric machinery.
Through all of its editions, the emphasis of Electric Machinery has been
on both physical insight and analytical techniques. Mastery of the material covered
will provide both the Basis for understanding many real-world electric-machinery
applications as well as the foundation for proceeding on to more advanced courses in
electric machinery design and control.
