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.
Wavelength division multiplexing (WDM) refers to a multiplexing and transmission
scheme in optical telecommunications fibers where different wavelengths, typically
emitted by several lasers, are modulated independently (i.e., they carry independent
information from the transmitters to the receivers). These wavelengths are then
multiplexed in the transmitter by means of passive WDM filters, and likewise they
are separated or demultiplexed in the receiver by means of the same filters or
coherent detection that usually involves a tunable Local oscillator (laser).
Today wireless is becoming the leader in communication choices among
users. It is not anymore a backup solution for nomadic travellers but really a
newmoodnaturallyusedeverywhereevenwhenthewiredcommunicationsare
possible. Many technologies evolve then continuously, changing the telecom-
munication world. We talk about wireless Local area networks (WLANs), wire-
less personal area networks (WPANs), wireless metropolitan area networks
(WMANs), wireless wide area networks (WWANs), mobile ad hoc networks
(MANETs), wireless sensor networks (WSNs) and mesh networks. Since we
can find today a multitude of wireless technologies we decided to group a
numberofcomplementarytechnologiesintoonedocumenttomakeiteasierfor
areadertounderstandsomeofthetechnicaldetailsofeachmedia.
Notwithstanding its infancy, wireless mesh networking (WMN) is a hot and
growing field. Wireless mesh networks began in the military, but have since
become of great interest for commercial use in the last decade, both in Local
area networks and metropolitan area networks. The attractiveness of mesh
networks comes from their ability to interconnect either mobile or fixed
devices with radio interfaces, to share information dynamically, or simply to
extend range through multi-hopping.
During the past three decades, the world has seen signifi cant changes in the telecom-
munications industry. There has been rapid growth in wireless communications, as
seen by large expansion in mobile systems. Wireless communications have moved
from fi rst-generation (1G) systems primarily focused on voice communications to
third-generation (3G) systems dealing with Internet connectivity and multi-media
applications. The fourth-generation (4G) systems will be designed to connect wire-
less personal area networks (WPANs), wireless Local area networks (WLANs) and
wireless wide-area networks (WWANs).
This chapter provides extensive coverage of existing mobile wireless technologies. Much of the
emphasis is on the highly anticipated 3G cellular networks and widely deployed wireless Local
area networks (LANs), as the next-generation smart phones are likely to offer at least these two
types of connectivity. Other wireless technologies that either have already been commercialized or
are undergoing active research and standardization are introduced as well. Because standardization
plays a crucial role in developing a new technology and a market, throughout the discussion
standards organizations and industry forums or consortiums of some technologies are introduced.
In addition, the last section of this chapter presents a list of standards in the wireless arena.
This book paves the path toward fourth generation (4G) mobile communica-
tion by introducing mobility in heterogeneous IP networks with both third
generation (3G) and wireless Local area networks (WLANs), which is seen as
one of the central issues in the becoming 4G of telecommunications networks
and systems. This book presents a thorough overview of 3G networks and
standards and discusses interworking and handover mechanisms between
WLANs and the Universal Mobile Telecommunication System (UMTS).
Battery systems for energy storage are among the most relevant technologies of the
21 st century. They – in particular modern lithium-ion batteries (LIB) – are enablers
for the market success of electric vehicles (EV) as well as for stationary energy
storage solutions for balancing fluctuations in electricity grids resulting from the
integrationofrenewableenergysourceswithvolatilesupply 1 .BothEVandstationary
storage solutions are important because they foster the transition from the usage
of fossil energy carriers towards cleaner renewable energy sources. Furthermore,
EV cause less Local air pollution and noise emissions compared to conventional
combustion engine vehicles resulting in better air quality especially in urban areas.
Unfortunately, to this day, various technological and economic challenges impede a
broad application of batteries for EV as well as for large scale energy storage and
load leveling in electricity grids.
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