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What is UMTS?UMTS (Universal Mobile Telecommunications System) was proposed as Europe’s candidate for IMT-2000 (International Mobile Telecommunications 2000) – the official standard for third generation (3G) networks from the ITU. Two things have prevented a unified approach to a single 3G standard: - spectrum allocation and network enabling technologies. On the spectrum allocation front, back in 1992 the World Administrative Radio Conference (WARC) allocated spectrum around the 2 GHz band for terrestrial and satellite services. Europe put the second set of GSM networks at 1800 MHz (Orange, One2One and Virgin in the UK) which is sufficiently far away not to interfere with the 2 GHz band. However, in the USA the 1900 MHz band has been adopted for what the Americans have termed PCS (Personal Communications Services) networks. Unfortunately, 1900 MHz equates to 1.9 GHz – too close to 2 GHz for comfort. So the ITU agreed a compromise where a whole range of different frequencies could be used for 3G. Hence the dream of everyone using 3G around the 2.1 GHz band disappeared. Next came problems with the which systems to use to build a 3G network. The EEC wanted to repeat its success with a GSM for 3G networks so it came up with UMTS. As a result of yet another compromise (this time between mainly European and Japanese manufacturers), a technology called Wideband CDMA (W-CDMA) became the official means for implementing UMTS. Although the ITU has accepted UMTS as an official standard for 3G, it also adopted two other standards: – CDMA2000 backed mainly by the USA and Korea, plus TD-SCDMA (Time Division- Synchronous CDMA) an outsider but invented by China, the biggest single market for mobile.
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