UMTS (Universal Mobile Telecommunications System) is a so-called "third-generation (3G)," broadband , packet -based transmission of text, digitized voice, video, and multimedia at data rates up to and possibly higher than 2 megabits per second ( Mbps ), offering a consistent set of services to mobile computer and phone users no matter where they are located in the world. Based on the Global System for Mobile ( GSM ) communication standard, UMTS, endorsed by major standards bodies and manufacturers, is the planned standard for mobile users around the world by 2002. Once UMTS is fully implemented, computer and phone users can be constantly attached to the Internet as they travel and, as they roaming service , have the same set of capabilities no matter where they travel to. Users will have access through a combination of terrestrial wireless and satellite transmissions. Until UMTS is fully implemented, users can have multi-mode devices that switch to the currently available technology (such as GSM 900 and 1800) where UMTS is not yet available.
Today's cellular telephone systems are mainly circuit-switched , with connections always dependent on circuit availability. packet-switched connection, using the Internet Protocol ( IP ), means that a virtual connection is always available to any other end point in the network. It will also make it possible to provide new services, such as alternative billing methods (pay-per-bit, pay-per-session, flat rate, asymmetric bandwidth, and others). The higher bandwidth of UMTS also promises new services, such as video conferencing. UMTS promises to realize the Virtual Home Environment ( VHE ) in which a roaming user can have the same services to which the user is accustomed when at home or in the office, through a combination of transparent terrestrial and satellite connections.
Trials of UMTS technology, using advanced mobile phone/computing device prototypes, are currently being conducted by Nortel Networks and BT (British Telecommunications).
The electromagnetic radiation spectrum for UMTS has been identified as frequency bands 1885-2025 MHz for future IMT-2000 systems, and 1980-2010 MHz and 2170-2200 MHz for the satellite portion of UMTS systems.