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Universal Mobile Telephone System

Universal Mobile Telephone System (UMTS) is one of the third-generation (3G) mobile phone technologies. It represents the European answer to the ITU-IMT2000 (International Telecommunications Union-International Mobile Telecommunication2000) requirements for 3G Cellular radio systems.

It supports up to 2 Mbit/s data transfer rates, although typical users can expect performance of around 64 kbit/s in a heavily loaded real-world system. However, this is still much greater than the 9600 bit/s of a single GSM, error-corrected data channel or multiple 9600 bit/s channels in HSCSD, and offers the first prospect of practical inexpensive access to the World Wide Web on a mobile device and general use of MMS. The precursor to 3G is the now widely used GSM mobile telephony system, referred as 2G. There is also an evolution path from 2G, called GPRS, alias 2.5G. GPRS supports a much better data rate (upto a maximum of 112kilobits per second) and deployed in many places where GSM is used.

Marketing material for UMTS has emphasised the possibility of mobile videoconferencing, although whether there is actually a mass market for this service remains untested.

Other possible uses for UMTS include the downloading of music.

There exists other proposals for the ITU-IMT2000 requirements for 3G systems besides UMTS like: CDMA2000 proposed under the American IS standards including 1xEVDO (up to 2 MByte/s data only), 1xEVDV (greater than 2 MByte/s with voice support)and other proprietary systems including iBurst from Arraycom, Flarion and wCDMA-TDD (IPWireless).

Universal Mobile Telecommunications System (UMTS) is a European 3rd generation mobile phone system. This broadband radio system targets to circuit and packet switching data services and offering multimedia services up to 2 Mbit/s. The services requiring lower data rate like phone calls a world wide coverage is established with satellites.

UMTS is based on GSM technology so that parts of GSM networks can be used as they are or with minor changes in UMTS. UMTS and other similar 3rd generation systems are targeted to be compliant to IMT-2000 family, where the same terminal equipment could be used around the world with the second generation systems. The frequency bands allocated to the 3rd generation systems are 1885–2025 MHz and 2110–2200 MHz.

The structure of UMTS resembles GSM system, but a major difference is the air interface forming Generic Radio Access Network (GRAN). It can be connected to various back bone networks like Internet, ISDN, GSM or to UMTS network. GRAN includes the three lowest layers of OSI model. The network layer (OSI 3) protocols form Radio Resource Management protocol (RRM). They manage the bearer channels between the mobile terminals and the fixed network including the handovers.

See also 3GPP - the 3G standardisation body.