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When 3GPP started standardizing the IMS a few years ago, most analysts expected the
number of IMS deploymentsto grow dramatically as soon the initial IMS specifications were
ready (3GPP Release 5 was functionallyfrozenin the first half of 2002and completedshortly
after that). While those predictions have proven to be too aggressive owing to a number of
upheavals hitting the ICT (Information and COMMUNICATIONs Technologies) sector, we are
now seeing more and more commercial IMS-based service offerings in the market. At the
time of writing (May 2008), there are over 30 commercial IMS networks running live traffic,
addingup to over10million IMS users aroundthe world; the IMS is beingdeployedglobally.
In addition, there are plenty of ongoing market activities; it is estimated that over 130 IMS
contracts have been awarded to all IMS manufacturers. The number of IMS users will grow
substantially as these awarded contracts are launched commercially. At the same time, the
number of IMS users in presently deployed networks is steadily increasing as new services
are introduced and operators running these networks migrate their non-IMS users to their
IMS networks.
標簽：
Multimedia
Subsystem
The
IMS
3G
IP
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When thinking about mobile radio engineers there is a tendency to
assume that the engineering function relates solely to the technical
aspects of the network, such as the equipment design or the network
design. That is certainly a key part of the role of a mobile radio engineer.
However,increasinglyengineersarerequiredtointeractwithprofession-
als from other divisions. The “complete wireless professional” should
know about mobile networks; fixed networks; other types of mobile
systems; regulatory and government policy; the requirements of the
users; and financial, legal, and marketing issues.
標簽：
COMMUNICATIONs
Complete
Wireless
The
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The first practical examples of mobile COMMUNICATIONs were used in many countries like
the USA, the UK and Germany in military services, and played a significant role in the
First World War to transfer important information from the front to headquarters to take
further actions. Good and secure wireless COMMUNICATIONs were an important need for all
military services – army, navy and air force. In this respect, the Second World War was a big
experimental battlefield for the development and evolution of mobile radio. It was in the
interests of governments that after the Second World War the military investment should
be paid back by civilian use, and all western European countries started their so-called first
generation of mobile communication networks.
標簽：
Multimedia
Business
Mobile
The
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2020-06-01
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When thinking about mobile radio engineers there is a tendency to
assume that the engineering function relates solely to the technical
aspects of the network, such as the equipment design or the network
design. That is certainly a key part of the role of a mobile radio engineer.
However,increasinglyengineersarerequiredtointeractwithprofession-
als from other divisions.
標簽：
COMMUNICATIONs
Professional
Complete
Wireless
The
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2020-06-01
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Long-TermEvolution(LTE)isarguablyoneofthemostimportantstepsinthecurrentphaseof
the development of modern mobile COMMUNICATIONs. It provides a suitable base for enhanced
services due to increased data throughput and lower latency figures, and also gives extra
impetus to the modernization of telecom architectures. The decision to leave the circuit-
switched domainoutofthescope ofLTE/SAEsystem standardization might soundradical but
itindicatesthatthetelecomworldisgoingstronglyfortheall-IPconcept----andthedeployment
of LTE/SAE is concrete evidence of this global trend.
標簽：
Deployment
Handbook
LTE-SAE
The
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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.”
標簽：
Time-Varying
Channels
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T
his book covers basic COMMUNICATIONs theory and practical imple-
mentation of transmitters and receivers. In so doing, I focus on dig-
ital modulation, demodulation methods, probabilities, detection of
digital signals, and spread spectrum system design and analysis. This book
was written for those who want a good understanding of the basic prin-
ciples of digital wireless communication systems, including spread spec-
trum techniques. This book also provides a good intuitive and practical
approach to digital COMMUNICATIONs. Therefore it is a valuable resource for
anyoneinvolvedinwirelessCOMMUNICATIONsandtransceiverdesignfordig-
ital COMMUNICATIONs. The reader will gain a broad understanding of basic
communication principles for transceiver design, digital COMMUNICATIONs,
and spread spectrum, along with examples of many types of commercial
and military data link systems.
標簽：
Transceiver
System
Design
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In this book we focus on the basic signal processing that underlies current and
future ultra wideband systems. By looking at signal processing in this way we
hope this text will be useful even as UWB applications mature and change or
regulations regarding ultra wideband systems are modified. The current UWB
field is extremely dynamic, with new techniques and ideas being presented at every
COMMUNICATIONs and signal-processing conference. The basic signal-processing
techniques presented in this text though will not change for some time to come.
Thus, we have taken a somewhat theoretical approach, which we believe is longer
lasting and more useful to the reader in the long term than an up-to-the-minute
summary that is out of date as soon as it is published.
標簽：
Wideband
Signals
Systems
Ultra
1st
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The continuing explosive growth in mobile communication is demanding more spectrally
efficient radio access technologies than the prevalent second generation (2G) systems such as
GSM to handle just the voice traffic. We are already witnessing high levels of mobile
penetration exceeding 70% in some countries. It is anticipated that by 2010 more than half of
all COMMUNICATIONs will be carried out by mobile cellular networks. On the other hand, the
information revolution and changing life habits are bringing the requirement of commu-
nicating on a multimedia level to the mobile environment. But the data handling capabilities
and flexibility of the 2G cellular systems are limited.
標簽：
Planning
Network
UMTS
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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.
標簽：
Communication
Visible
Light
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2020-06-01
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