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White Paper V600
16 August 2005
How 3G works
3G brings together two powerful forces: wideband
radio communications and IP-based services.
Together, these enable advanced multimedia serv-
ices.
Making 3G a reality depends on technology devel-
opments in different areas. These include amend-
ments to the radio interface to support wideband
communications, as well as amendments in the
core network. Supporting technologies such as
WAP, Bluetooth, Java, MMS and streaming, are
also important.
GPRS
Short for General Packet Radio Service, GPRS is a
standard for wireless communications.
GPRS provides packet data, rather than circuit
switched data. This means that as a user you pay
for data sent and received, and not for time spent
online. There is, more or less, a permanent connec-
tion at all times.
GPRS is implemented by adding new packet data
nodes and upgrading existing nodes, to provide a
routing path for packet data between the mobile
terminal and a gateway node. The gateway node
will provide interworking with external packet data
networks for access to the Internet and intranets.
Benefits
• Faster data speeds and “permanent connec-
tion” mobility.
• Instantaneous connection set-up.
• Connection to an abundance of data sources
around the world, through support for multiple
protocols, including IP.
WCDMA
WCDMA (Wideband Code Division Multiple
Access) is a wideband radio technique that pro-
vides far higher data rates than other radio tech-
niques available today, up to 384 kbps, and highly
efficient use of radio spectrum.
The higher bandwidth that WCDMA provides will
deliver the full potential of 3G. For example,
WCDMA allows simultaneous access to several
voice, video and data services.
WCDMA is fully compliant with IMT-2000 (Interna-
tional Mobile Telecommunications-2000) and is the
air interface technology for standards in the 2 GHz
band (the IMT-2000 core band), known as UMTS
(Universal Mobile Telecommunication System) in
Europe and ARIB (Association of Radio Industry
Businesses) in Japan.
UMTS
UMTS and WCDMA are often used as synonyms.
The European Telecommunications Standard Insti-
tute (ETSI) chose the name UMTS to define the
system when positioned in the 2.1 GHz band,
which will be the case in Europe and other parts of
the world where this frequency is available. In the
Americas though, WCDMA will have to use other
parts of the frequency band.
UMTS is part of the International Telecommunica-
tions Union’s IMT-2000 vision of a global family of
3G mobile communications systems. UMTS
includes WCDMA radio access technologies
together with a core network specification based
on the GSM/MAP (Mobile Application Part) stand-
ard. Please visit the 3GPP site for more information
at www.3gpp.org
.
Handover/service continuity
The scope of this text includes service require-
ments for handover maintaining continuity of serv-
ice to a wireless terminal, as it moves between the
radio coverage area, or “cells”, associated with dif-
ferent base station sites. This functionality is called
“handover”. It is a key requirement to allow for dual
or multi-mode terminals to handover traffic from
UTRAN to other radio systems such as GERAN and
vice versa.
This part describes the general principles for serv-
ice continuity within UMTS Radio Access Network,
within GSM/GPRS and between UMTS Radio