Universal Mobile Telecommunications System (UMTS) is one of the third-generation (3G) mobile phone technologies. It uses W-CDMA as the underlying standard, is standardized by the 3GPP, and represents the European answer to the ITU IMT-2000 requirements for 3G Cellular radio systems.

Table of contents

1 Features 2 Technology 3 Other Standards

Features

UMTS 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 14.4 kbit/s of a single GSM error-corrected data channel or multiple 14.4 kbit/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, also known as 2.5G. GPRS supports a much better data rate (up to a maximum of 140.8kbit/s) and is packet based rather than connection oriented. It is 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.

Technology

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 3G 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 3G systems are 1885–2025 MHz and 2110–2200 MHz.

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

Other Standards