WCDMA System

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Air Interfaces for 3rd Generation Systems


Since 1985, ITU (International Telecommunications Union) has
been developing IMT-2000, previously termed Future Public Land
Mobile Telephone System (FPLMTS).
In 1992, the World Administrative Radio Conference (WARC) of
the ITU identified the frequencies around 2 GHz for future 3rd
generation mobile systems, both terrestrial and satellite.
Within the ITU, the 3rd generation systems are called
International Mobile Telephony 2000 (IMT-2000). In Europe, it
is called UMTS (Universal Mobile Telephone Service).
Original target: a single common global IMT-2000 air interface.
Specification has been created in 3GPP (the 3rd Generation
Partnership Project), which is the joint standardisation project of
the standardisation bodies from Europe, Japan, Korea, the USA
and China.



Europe
RACE I (Research of Advanced Communication Technologies
in Europe) program started the basic 3rd generation research
work in 1988.
RACE II program develops the CDMA-based CODIT (Code
Division Testbed) and TDMA-based ATDMA (Advanced
TDMA Mobile Access) air interfaces during 1992-95.
European research program ACTS (Advanced Communication
Technologies and Services) was launched at the end of 1995 to
support mobile communications research and development.
Within ACTS, the FRAMES (Future Radio Wideband Multiple
Access System) project was set up to define a proposal for a
UMTS radio access system.
Nokia, Siemens, Ericsson, France Telecom, CSEM/Pro Telecom.


Japan
ARIB (the Association for Radio Industries and
Businesses) was established in April 1993 to evaluate
possible 3rd generation systems around three different
main technologies based on WCDMA, WTDMA and
OFDMA.
The WCDMA technology in Japan was very similar to
that being considered in Europe in ETSI.
ARIB selected WCDMA, with both FDD and TDD
modes operation, in 1997.
WCDMA was chosen in ARIB before the process was
completed in ETSI.
ARIB contributed their WCDMA to 3GPP.


The United States
Main standardization activities for wireless systems are carried out in
TIA Engineering Committee TR45 and TR46, and in the T1
committee T1P1.
TR45.5 is responsible for the IS-95, TR45.3 for the IS-136, and T1P1
with TR46 are jointly for GSM1900.
Industry forums: UWCC for IS-136, CDMA Development Group
(CDG) for IS-95, and the GSM Alliance and GSM North America for
GSM.
In April 1997, CDG issued the Advanced Systems initiative to develop
the IS-95 based 3rd generation air interface proposal.
In 1997, proposals from Hughes, Lucent, Motorola, Nokia, Nortel,
Qualcomm, and Samsung, were submitted to TR45.5 for cdma2000,
all backward compatible to IS-95.
In March 1998, TR45.5 agreed on the basic framework for cdma2000:
cdma2000 1x has same bandwidth as IS-95 (1.25 MHz) and cdma2000
3x, also called multicarrier CDMA, three times the bandwidth of IS-95.