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With the rapid growth in the number of wireless applications, services and devices,
using a single wireless technology such as a second generation (2G) and third gener-
ation (3G) wireless system would not be efficient to deliver high speed data rate and
quality-of-service (QoS) support to mobile users in a seamless way. The next genera-
tion wireless systems (also sometimes referred to as Fourth generation (4G) systems)
are being devised with the vision of heterogeneity in which a mobile user/device will
be able to connect to multiple wireless networks (e.g., WLAN, cellular, WMAN)
simultaneously.
標簽：
Heterogeneous
Wireless
Networks
Access
上傳時間：
2020-05-27
上傳用戶：shancjb
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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.
標簽：
HSDPAHSUPA
Access
Speed
Radio
UMTS
High
for
上傳時間：
2020-05-27
上傳用戶：shancjb
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With the rapid growth of the wireless mobile applications, wireless voice has
begun to challenge wireline voice, whereas the desire to access e-mail, surf the
Web or download music (e.g., MP3) wirelessly is increasing for wireless data.
While second generation (2G) cellular wireless systems, such as cdmaOne1,
GSM2 and TDMA3, introduced digital technology to wireless cellular systems
to deal with the increasing demand for wireless applications, there is still the
need for more spectrally efficient technologies for two reasons. First, wireless
voice capacity is expected to continue to grow. Second, the introduction of
high-speed wireless data will require more bandwidth.
標簽：
Wireless
Systems
Mobile
Beyond
and
3G
上傳時間：
2020-05-30
上傳用戶：shancjb
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At recent major international conferences on wireless communications,
there have been several sessions on beyond third generation (3G) or fourth
generation(4G)mobilecommunicationssystems,wheremodulation/demod-
ulation and multiplexing/multiple access schemes related to multicarrier
techniques have drawn a lot of attention. We often met at the conference
venuesandrealizedthatnobookcoveredthebasicsofmulticarriertechniques
to recent applications aiming at the 4G systems. Therefore, we decided to
write a book on multicarrier techniques for 4G mobile communications
systems.
標簽：
Communications
Multicarrier
Techniques
Mobile
for
4G
上傳時間：
2020-05-31
上傳用戶：shancjb
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It is more than a decade since GSM was first commercially available. After some unexpected delay, it
seems that finally UMTS is here to stay as a 3G system standardised by 3GPP, at least for another ten
years. UMTS will enable multi-service, multi-rate and flexible IP native-based mobile technologies to be
used in wide area scenarios and also pave the way for a smooth transition from circuit switched voice
networks to mobile packet services.
標簽：
Management
Strategies
Resource
Radio
上傳時間：
2020-06-01
上傳用戶：shancjb
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Convergence between the two largest networks (Telecom and IP) is taking place
very rapidly and at diff erent levels: (1) network level: unifi cation of IP networks
with traditional Telecom networks through evolving standards (Session Initiation
Protocol (SIP), Realtime Transfer Protocol (RTP), SS7, 3G) to support interopera-
bility; (2) service level: traditional Telecom services like voice calls are being provi-
sioned on the IP backbone (VoIP), while traditional IP services (most data-driven
services such as multimedia, browsing, chatting, gaming, etc.) are accessible over
the Telecom network.
標簽：
Platforms
Delivery
Service
上傳時間：
2020-06-01
上傳用戶：shancjb
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Software defined radio (SDR) is an exciting new field for the wireless indus-
try; it is gaining momentum and beginning to be included in commercial
and defense products. The technology offers the potential to revolutionize
the way radios are designed, manufactured, deployed, and used. SDR prom-
ises to increase flexibility, extend hardware lifetime, lower costs, and reduce
time to market
標簽：
Software
Defined
Radio
for
3G
上傳時間：
2020-06-01
上傳用戶：shancjb
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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
上傳時間：
2020-06-01
上傳用戶：shancjb
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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
上傳時間：
2020-06-01
上傳用戶：shancjb
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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).
標簽：
Communications
Networking
Wireless
上傳時間：
2020-06-01
上傳用戶：shancjb
