UMTS History
As GSM deployments were occuring in Europe and elsewhere in the
early 1990s, ETSI in the mid-1990s was investigating several technologies that
would meet the requirements specified by ITU as part of IMT-2000. One of the
critical roles was the evaluation of the radio access system to be used for
UMTS. Among the several proposals that were being evaluated for the air
interface, WCDMA was selected by ETSI as the technology of choice. This was also
partly influenced by other countries (including Japan and Korea) selecting WCDMA
as the preferred radio technology for 3G networks.
At the same time, other standards bodies were working on
specifications for meeting the IMT-2000 requirements. In order to coordinate the
standardization of WCDMA and the specification of a common technology on a
global basis, several standards organizations and companies (including vendors
and operators) created a partnership in 1998 called third-generation partnership
project (3GPP).
The scope of 3GPP was to produce a globally applicable standard for a 3G mobile
system based on the evolution of GSM networks and the radio access technologies
that they support. The scope was subsequently amended to include the maintenance
and development of the Global System for Mobile communication (GSM).
Standardization efforts also include evolved radio access technologies such as
GPRS and EDGE.
3GPP released its first version of the specifications for UMTS
in 1999, referred to as Release 99. The access networks in Release 99 include
GPRS, EDGE, and WCDMA-based UTRAN. Further releases include Release 4, which
included minor enhancements and corrections and was completed in 2001, and
Release 5, which concluded in 2002. Release 5 includes a new subsystem called
the IP multimedia subsystem (IMS), which is based on IPv6 and supports new
services and support for the IETF's Session Initiation Protocol (SIP). Release 5
also enhances WCDMA radio technology with high-speed downlink packet access.
With this enhancement, data rates up to 10 Mbps can be achieved on the downlink.
Work on Release 6 is ongoing and aspects of this are discussed in Chapter 15.
Sections
