The insinuation of telecommunications into the daily fabric of our lives has been
arguably the most important and surprising development of the last 25 years. Before
this revolution, telephone service and its place in our lives had been largely stable
for more than a generation. The growth was, so to speak, lateral, as the global reach
of telecommunications extended and more people got telephone service. The
distinction between oversea and domestic calls blurred with the advances in
switching and TransmisSion, undersea cable, and communication satellites. Traffic
on the network remained overwhelmingly voice, largely in analog format with
facsimile (Fax) beginning to make inroads.
Advances in communication and networking technologies are rapidly making ubiq-
uitous network connectivity a reality. Wireless networks are indispensable for
supporting such access anywhere and at any time. Among various types of wire-
less networks, multihop wireless networks (MWNs) have been attracting increasing
attention for decades due to its broad civilian and military applications. Basically,
a MWN is a network of nodes connected by wireless communication links. Due
to the limited TransmisSion range of the radio, many pairs of nodes in MWNs may
not be able to communicate directly, hence they need other intermediate nodes to
forward packets for them. Routing in such networks is an important issue and it
poses great challenges.
This book is about multipoint cooperative communication, a key technology to
overcome the long-standing problem of limited TransmisSion rate caused by inter-
point interference. However, the multipoint cooperative communication is not an
isolated technology. Instead, it covers a vast range of research areas such as the
multiple-input multiple-outputsystem, the relay network, channel state information
issues, inter-point radio resource management operations, coordinated or joint
TransmisSions, etc. We suppose that any attempt trying to thoroughly analyze the
multipoint cooperative communication technology might end up working on a
cyclopedia for modern communication systems and easily get lost in discussing all
kinds of cooperative communication schemes as well as the associated models and
their variations.
his research aims at creating broadband tunable, fully integrated filters for the application of
cognitive radio and signal classification receivers. The approach under study is the N-path filter
technique which is capable of translating a baseband impedance to a reference frequency creating
a tunable filter. The traditional N-path filter suffers from fundamental architectural limitations,
namely : a trade-off between insertion loss and out-of-band rejection, reference clock feed-
through, and jammer power handling limitations. In the first approach, the fundamental trade-
off of the traditional N-path filter between insertion loss and out-of-band rejection is improved by
a TransmisSion line (T-line) N-path filter technique.
Ever since ancient times, people continuously have devised new techniques and
technologies for communicating their ideas, needs, and desires to others. Thus,
many forms of increasingly complex communication systems have appeared
over the years. The basic motivations behind each new one were to improve the
TransmisSion fidelity so that fewer errors occur in the received message, to
increase the TransmisSion capacity of a communication link so that more infor-
mation could be sent, or to increase the TransmisSion distance between relay sta-
tions so that messages can be sent farther without the need to restore the signal
fidelity periodically along its path.
The ever-increasing demand for private and sensitive data TransmisSion over wireless net-
works has made security a crucial concern in the current and future large-scale, dynamic,
and heterogeneous wireless communication systems. To address this challenge, computer
scientists and engineers have tried hard to continuously come up with improved crypto-
graphic algorithms. But typically we do not need to wait too long to find an efficient way
to crack these algorithms. With the rapid progress of computational devices, the current
cryptographic methods are already becoming more unreliable. In recent years, wireless re-
searchers have sought a new security paradigm termed physical layer security. Unlike the
traditional cryptographic approach which ignores the effect of the wireless medium, physi-
cal layer security exploits the important characteristics of wireless channel, such as fading,
interference, and noise, for improving the communication security against eavesdropping
attacks. This new security paradigm is expected to complement and significantly increase
the overall communication security of future wireless networks.
In this book, we present the basic pinciples that underlie the analysis and design of digital communication system.The subject of digital communications involves the TransmisSion of information in digital form from a source that generates the information to one or more destinations.
Wireless means different things to different people. For this book, it refers
to the radio systems that provide point-to-point, point-to-multipoint, and
Earth-space communications over TransmisSion links that propagate outside
buildings through the lower atmosphere. Wireless systems are being built
that provide data TransmisSion between computers and other devices on
one’s own desk. These are part of the wireless world but not the part where,
except for interference perhaps, the atmosphere has any influence. The intent
of this book is to provide a description of the physical phenomena that can
affect propagation through the atmosphere, present sample measurements
and statistics, and provide models that system designers can use to calculate
their link budgets and estimate the limitations the atmosphere may place on
their design.
One of the prerequisites for the development of telecommunication services is the
understanding of the propagation of the waves, either acoustic, electromagnetic,
radio or light waves, which are used for the TransmisSion of information.
In this work, we shall limit ourselves to the study of radio waves: this term
apply to the electromagnetic waves used in radio communications. Their
frequency spectrum is very broad, and is divided into the following frequency
bands : ELF waves (f < 3 kHz), VLF (3-30 kHz), LF waves (30-300 kHz), MF
waves (300-3000 kHz), HF (3-30 MHz), VHF waves (30-300 MHz), UHF waves
(300-3000 MHz), SHF waves (3-30 GHz), EHF waves (30-300 GHz) and sub-
EHF waves (300-3000 GHz).
By inventing the wireless transmitter or radio in 1897, the Italian physicist Tomaso
Guglielmo Marconi added a new dimension to the world of communications. This
enabled the TransmisSion of the human voice through space without wires. For this
epoch-making invention, this illustrious scientist was honored with the Nobel Prize
for Physics in 1909. Even today, students of wireless or radio technology remember
this distinguished physicist with reverence. A new era began in Radio
Communications.
