Cognitive radios have become a vital solution that allows sharing of the scarce
frequency spectrum available for wireless systems. It has been demonstrated
that it can be used for future wireless systems as well as integrated into 4G/5G
wireless systems. Although there is a great amount of literature in the design of
cognitive radios from a system and networking point of view, there has been very
limited available literature detailing the circuit implementation of such systems.
Our textbook, Radio Frequency Integrated Circuit Design for Cognitive Radios, is
the first book to fill a disconnect in the literature between Cognitive Radio systems
and a detailed account of the circuit implementation and architectures required to
implement such systems. In addition, this book describes several novel concepts
that advance state-of-the-art cognitive radio systems.
The single-carrier frequency division multiple access (SC-FDMA)
system is a well-known system that has recently become a preferred
choice for mobile uplink channels. This is attributed to its advantages
such as the low peak-to-average power ratio (PAPR) and the use of
frequency domain equalizers. Low PAPR allows the system to relax
the specifications of linearity in the power amplifier of the mobile
terminal, which reduces cost and power consumption.
The radio spectrum is one of the most precious resources which must be managed
to ensure efficient access for the wireless communication services which use it. The
allocation and management of spectrum are administered by the regulatory
authorities. Traditionally, spectrum allocation is carried out exclusively of its use in
large geographic areas and assigning frequency bands to specific users or service
providers is proved to be inefficient. Recently, substantial knowledge about
dynamic spectrum access scheme has been accumulated to enable efficient spectrum
sharing.
Radio frequency spectrum is a scarce and critical natural resource that is utilized for
many services including surveillance, navigation, communication, and broadcast-
ing. Recent years have seen tremendous growth in the use of spectrum especially by
commercial cellular operators. Ubiquitous use of smartphones and tablets is one
of the reasons behind an all-time high utilization of spectrum. As a result, cellular
operators are experiencing a shortage of radio spectrum to meet bandwidth
demands of users. On the other hand, spectrum measurements have shown that
much spectrum not held by cellular operators is underutilized even in dense urban
areas. This has motivated shared access to spectrum by secondary systems with no
or minimal impact on incumbent systems. Spectrum sharing is a promising
approach to solve the problem of spectrum congestion as it allows cellular operators
access to more spectrum in order to satisfy the ever-growing bandwidth demands of
commercial users.
Part I provides a compact survey on classical stochastic geometry models. The basic models defined
in this part will be used and extended throughout the whole monograph, and in particular to SINR based
models. Note however that these classical stochastic models can be used in a variety of contexts which
go far beyond the modeling of wireless networks. Chapter 1 reviews the definition and basic properties of
Poisson point processes in Euclidean space. We review key operations on Poisson point processes (thinning,
superposition, displacement) as well as key formulas like Campbell’s formula. Chapter 2 is focused on
properties of the spatial shot-noise process: its continuity properties, its Laplace transform, its moments
etc. Both additive and max shot-noise processes are studied. Chapter 3 bears on coverage processes,
and in particular on the Boolean model. Its basic coverage characteristics are reviewed. We also give a
brief account of its percolation properties. Chapter 4 studies random tessellations; the main focus is on
Poisson–Voronoi tessellations and cells. We also discuss various random objects associated with bivariate
point processes such as the set of points of the first point process that fall in a Voronoi cell w.r.t. the second
point process.
Wireless communications has become a field of enormous scientific and economic interest. Recent
success stories include 2G and 3G cellular voice and data services (e.g., GSM and UMTS), wireless
local area networks (WiFi/IEEE 802.11x), wireless broadband access (WiMAX/IEEE 802.16x), and
digital broadcast systems (DVB, DAB, DRM). On the physical layer side, traditional designs typically
assume that the radio channel remains constant for the duration of a data block. However, researchers
and system designers are increasingly shifting their attention to channels that may vary within a block.
In addition to time dispersion caused by multipath propagation, these rapidly time-varying channels
feature frequency dispersion resulting from the Doppler effect. They are, thus, often referred to as
being “doubly dispersive.”
Recent advances in wireless communication technologies have had a transforma-
tive impact on society and have directly contributed to several economic and social
aspects of daily life. Increasingly, the untethered exchange of information between
devices is becoming a prime requirement for further progress, which is placing an
ever greater demand on wireless bandwidth. The ultra wideband (UWB) system
marks a major milestone in this progress. Since 2002, when the FCC allowed the
unlicensed use of low-power, UWB radio signals in the 3.1–10.6GHz frequency
band, there has been significant synergistic advance in this technology at the cir-
cuits, architectural and communication systems levels. This technology allows for
devices to communicate wirelessly, while coexisting with other users by ensuring
that its power density is sufficiently low so that it is perceived as noise to other
users.
Once upon a time, cellular wireless networks provided two basic services: voice
telephony and low-rate text messaging. Users in the network were separated
by orthogonal multiple access schemes, and cells by generous frequency reuse
patterns [1]. Since then, the proliferation of wireless services, fierce competition,
andthe emergenceof new service classes such as wireless data and multimediahave
resulted in an ever increasing pressure on network operators to use resources in a
moreefficient manner.In the contextof wireless networks,two of the most common
resources are power and spectrum—and, due to regulations, these resources are
typically scarce. Hence, in contrast to wired networks, overprovisioning is not
feasible in wireless networks.
Visible light communications (VLC) is the name given to an optical wireless
communication system that carries information by modulating light in the visible spectrum
(400–700 nm) that is principally used for illumination [1–3]. The communications signal
is encoded on top of the illumination light. Interest in VLC has grown rapidly with the
growth of high power light emitting diodes (LEDs) in the visible spectrum. The
motivation to use the illumination light for communication is to save energy by exploiting
the illumination to carry information and, at the same time, to use technology that is
“green” in comparison to radio frequency (RF) technology, while using the existing
infrastructure of the lighting system.
Although the origins of radio frequency based wireless networking can be
traced back to the University of Hawaii’s ALOHANET research project
in the 1970s, the key events that led to wireless networking becoming
one of the fastest growing technologies of the early 21st century have
been the ratification of the IEEE 802.11 standard in 1997, and the
subsequent development of interoperability certification by the Wi-Fi
Alliance (formerly WECA).
