Wireless penetration has witnessed explosive growth over the last two decades.
Accordingly, wireless devices have become much denser per unit area, resulting
in an overcrowded usage of wireless resources. To avoid radio interferences and
packet collisions, wireless stations have to exchange control messages to coordinate
well. The EXISTING wisdoms of conveying control messages could be classified into
three categories: explicit, implicit, or hybrid.
According to the statistics of the Federal Communications Commission
(FCC), temporal and geographical variations in the utilization of the as-
signed spectrum range from 15% to 85%. The limited available radio spec-
trum and the inefficiency in spectrum usage necessitate a new commu-
nication paradigm to exploit the EXISTING spectrum dynamically.
The new digital radio system DAB (Digital Audio Broadcasting, nowadays often called
Digital Radio) is a very innovative and universal multimedia broadcast system which will
replace the EXISTING AM and FM audio broadcast services in many parts of the world in
the future. It was developed in the 1990s by the Eureka 147/DAB project. DAB is very
well suited for mobile reception and provides very high robustness against multipath
reception. It allows use of single frequency networks (SFNs) for high frequency
efficiency.
The first Third Generation Partnership Project (3GPP) Wideband Code Division
Multiple Access (WCDMA) networks were launched during 2002. By the end of 2005
there were 100 open WCDMA networks and a total of over 150 operators having
frequency licenses for WCDMA operation. Currently, the WCDMA networks are
deployedinUniversalMobileTelecommunicationsSystem(UMTS)bandaround2GHz
in Europe and Asia including Japan and Korea. WCDMA in America is deployed in the
EXISTING 850 and 1900 spectrum allocations while the new 3G band at 1700/2100 is
expected to be available in the near future. 3GPP has defined the WCDMA operation
also for several additional bands, which are expected to be taken into use during the
coming years.
This paper covers the keynote address delivered by the
Chairman of the COST Action 285 at the Symposium. It outlines the
studies undertaken by the members of the Action with the objective of
enhancing EXISTING modeling and simulation tools and to develop new ones
for research in emerging multiservice telecommunication networks. The
paper shows how the scope of COST Action 285 has been enriched by the
contributions made at the Symposium.
All wireless communication standards, EXISTING and under development, adopt or
consider adopting orthogonal frequency-division multiplexing (OFDM) as the
modulation technique. It is clear that OFDM has become the definitive modulation
scheme in current and future wireless communication systems.
Developers, manufacturers and marketers of products incorporating short-
range radio systems are experts in their fields—security, telemetry,
medical care, to name a few. Often they add a wireless interface just to
eliminate wires on an EXISTING wired product. They may adapt a wireless
subsystem, which is easy to integrate electrically into their system, only to
find that the range is far short of what they expected, there are frequent
false alarms, or it doesn’t work at all. It is for these adapters of wireless
subsystems that this book is primarily intended.
Rapid progress in information and communications technology (ICT) induces
improved and new telecommunications services and contributes greatly to society
in general and to vendors and network and service providers. In addition to EXISTING
services such as telephony or leased line services, spread of the Internet, the Internet
Protocol (IP) phone, and new communications services like IPTV are making great
progress with the development of digital subscriber lines (DSL) and high - speed
communications technologies like fi ber to the home (FTTH).
Public telephone operators and new independent wireless operators through-
out the world are deploying wireless access in an effort to drastically reduce
delivery costs in the most expensive part of the network?the local loop.
Available radio technology enables both EXISTING and new entrants to access
subscribers in a rapid manner and deliver their basic telephony products and
broadband-enhanced services.
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.
