3G Defined
3G (Third Generation) is a generic name for a set of mobile technologies set to
be launched by the end of 2001 which use a host of high-tech infrastructure networks, handsets, base stations, switches
and other equipment to allow mobiles to offer high-speed Internet access, data, video and CD-quality music services.
Data speeds in 3G networks should be show speeds of to up to 2
Megabits per second, an increase on current technology.
2G/2.5G Defined
GSM for example is a 2G technology. It
uses TDMA technology, proving data speeds of 9.6kbps/14.4kbps. The packet radio upgrade to GSM, called GPRS,
can have speeds of up to 114kbps. GPRS an interim technology towards 3G, and hence is known as 2.5G. GSM might go
the same way as the older first generation (1G) NMT and AMPS networks in 8-15 years because of the use of newer
and better UMTS technology
CDMA
The new 3G services are almost all flavours of technolgies based on the generic name, CDMA (Code
Division Multiple Access). CDMA is a digital wireless technology that allows multiple users to share radio
frequencies at the same time without interfering with each other. A telephone or data call is assigned a unique code
that distinguishes it from others and and since the signals hop among different frequencies.
Current 2G services using the original CDMA "IS-95" technology are
know as cdmaOne. 3G services will use new high-speed versions of CDMA called W-CDMA,
or its competing technology, cdma2000.
IMT-2000
IMT-2000 In all, these technologies fall under the ITUs generic name of IMT-2000
(International Mobile Telecommunications 2000). But when the ITU tried to unify and standardise 3G technologies, no
consensus was reached. There were thus five terrestrial standards developed as part of the IMT-2000 program. Instead,
depending on where in the world 3G will be implemented, the 3G standard will be based on CDMA variants cdma2000 or
W-CDMA.
CDMA 3G Variants
CDMA 3G Variants (in the IMT-2000 Family) The primary CDMA variants that will be used
in IMT-2000 3G networks are W-CDMA (Wideband CDMA) and cdma2000, which are similar but not the same, so
that W-CDMA handsets will not work with cdma2000 handsets and visa versa.
W-CDMA (Wideband CDMA)
W-CDMA (Wideband CDMA) W-CDMA is the competitor to cdma2000 and one of two 3G
standards that makes use of a wider spectrum than CDMA and therefore can transmit and receive information for faster and
more efficiently.
Co-developed by NTT DoCoMo, it is being backed by most European mobile operators and
is expected to compete with cdma2000 to be the de facto 3G standard UMTS
(W-CDMA) In Europe, 3G W-CDMA networks are known as UMTS (Universal Mobile Telephony
System) another name for w-CDMA/3G services. Governments in the region held UMTS auctions for 3G licences netting
$108 billion in 2000. FOMA (W-CDMA)
Japanese giant NTT DoCoMo Inc brand name for 3G services is FOMA (Freedom of Mobile Multimedia Access).
Based on the W-CDMA format, FOMA services for a limited number of users is to begin at
the end of May, with full commercial services due in October 2001. cdma2000
Then there is cdma2000, the other 3G standard. It is the upgarde to cdmaOne. It
can use of a wider spectrum than CDMA and therefore can transmit and receive information faster and more efficiently,
making fast Internet data, video, and CD-quality music transmission possible. There are however new cdma2000 variants
called cdma2000 1X, 1X-EV-DV, 1X EV-DO, and cdma2000 3X.
They deliver 3G services while occupying a very small amount of current spectrum (1.25
MHz per carrier) as opposed to UMTS which requires completely NEW spectrum (hence the auctions).
That is why cddma2000 is considered slightly more technologically advanced than the competing
W-CDMA standard. CDMA2000 is not constrained to only the IMT band; it is defined to operate in existing cellular and PCS
spectrum as well as IMT spectrum, thereby maximizing flexibility for operators. Cdma2000 is expected to be compatible
with with CDMA and GSM/TDMA networks so that GSM networks can "overlay" a cdma2000 network over their GSM
networks.
GPRS (General Packet Radio Services)
GPRS Terminals can provide up to 170kbps data speeds!
GSM's new GPRS (General Packet Radio Services) data transmission
technology is optimized for "bursty" datacom services such as wireless Internet/intranet and multimedia
services. It is also known as GSM-IP (Internet Protocol) because it will connect users directly to
Internet Service Providers.
One of the main benefits of this new packet-switched technology is that
users are always connected, always on-line, and may be charged only for the amount of data that is transported.
Voice calls can be made simultaneously over GSM-IP while a data connection is operating - depending on the phone Class
and Type.
In a Class 8 device for example, there are four times as many receive
channels as there are transmit channels, to accommodate the higher bandwidth demands of data reception.
A class B terminal means that in the idle mode, there is a choice of
whether to make a voice call, which would be with a circuit switched connection or whether to transmit data, which would
be sent in a packet format.
Users will also benefit from fast and easy 170 kbps data access
to different services.
Ericsson for example offers
a robust IP end-to-end GPRS solution with open interfaces enabling integration into multi-vendor networks.
The company's GPRS solution also offers leading-edge security for
wireless use of intranet and corporate LAN services.
GPRS is a smooth add-on to integrate into existing networks. For new
operators, it's also attractive to launch GPRS networks to provide competitive datacom services.
GPRS roaming
GPRS roaming is a basic requirement for making future global mobile
Internet services possible for GPRS subscribers in other operators' GPRS networks.
GRX, as specified in the IR.34 recommendations laid down by the
International Roaming Expert Group (IREG) of the GSM Association, is a centralised IP routing network for
interconnecting GPRS networks. GRX based GPRS roaming has now been implemented successfully for the first time in the
world, with a solution that is fully compliant with the GSM Association recommendation. The tests were executed by
combining Sonera's GPRS system and Nokia's packet core network by a backbone network solution that uses Sonera's GPRS
Roaming Exchange. The solution is also designed to meet the roaming needs of future 3G networks.
Motorola's GPRS solution
introduces two new network nodes into the GSM PLMN (Public Land Mobile Network) - the SGSN and the GGSN.
A number of new interfaces are added to connect the SGSN and GGSN to
the appropriate GSM and non-GSM elements required to provide global packet data service.
Motorola's GPRS infrastructure solution is designed around a powerful
IP routing engine, providing operators with a scalable and flexible solution that can tailor the packet switching
capability in line with the predicted data subscriber growth.
The SGSN tracks packet capable mobile locations, performs
security functions and access control. The GGSN interfaces with external packet data networks (PDNs) to provide the
routing destination for data to be delivered to the subscriber's mobile terminal and to send mobile-originated data to
its intended destination.
The GGSN is connected with SGSNs via an IP-based GPRS backbone
network. The PCU performs radio functions and GPRS network functions. The PCU interfaces to the OMC-G, base station
controller and SGSN.
Earlier in 1999, Motorola and Cisco Systems Inc., the worldwide
leader in networking for the Internet, announced a strategic alliance to develop and deliver a New World framework for
Internet-based, wireless networks. This collaboration will deliver the first all-IP platform for the wireless industry,
which unites different standards for wireless services worldwide, and introduce an open, Internet-based platform for
integrated data, voice and video services over cellular networks.
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