Rapid growth of wireless communication services in recent decades has created
a huge demand of radio spectrum. Spectrum scarcity and utilization inefficiency
limit the development of wireless networks. Cognitive radio is a promising tech-
nology that allows secondary users to reuse the underutilized licensed spectrum of
primary users. The major challenge for spectrum sharing is to achieve high spectrum
efficiency while making non-intrusive access to the licensed bands. This requires in-
formation of availability and quality of channel resources at secondary transmitters,
however, is difficult to be obtained perfectly in practice.
This book was born from the perception that there is much more to spectrum use
and sharing than one sees reflected in publications, whether academic, commercial
or political. the former – in good research style – tend towards reductionism and
concentrate on specific, detailed aspects. commercial publications tend to empha-
size the positive aspects and they tend to put promise above practice. Given the ever
increasing pace of technology development and recent successes of new wireless
technologies, some pundits predict large-scale spectrum scarcity, potentially lead-
ing to economic catastrophe. Although economic theory has a hard time explaining
recent events that shook the world economy, the notion of spectrum scarcity is intui-
tively acceptable, even if not correct or immediately relevant.
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.
RECOMMENDATION ITU-R M.1653*,**
Operational and deployment requirements for wireless access systems including radio local area networks in the mobile service to facilitate sharing between these systems and systems in the Earth exploration-satellite service (active)
and the space research service (active) in the band 5 470-5 570 MHz
within the 5 460 5 725 MHz range
Distributed applications, devices, and services appear in many different arrangements in an
enterprise. At your company, you probably access data from your intranet services, from
computers distributed throughout the company network, and from services across the firewall out
on the Web. For example, you might access a calendar-sharing application or a financial
application to fill out expense sheets. Someone must maintain all these applications. Not only the
applications, but also the hardware that supports them must be maintained. Resource management
encompasses both applications and hardware. In fact, both application and hardware management
can be supported through the development of Java Management Extensions (JMX) resource
management software. This book will show how you can use JMX to manage and monitor all
your resources across an enterprise—both software and hardware.
