IMT-2000 is the term used by the International Telecommunications Union (ITU) for a set of globally harmonized standards for third generation (3G) mobile telecoms services and equipment. 3G services are designed to offer broadband cellular access at speeds of 2Mbps, which will allow mobile multimedia services to become possible. In 1998, the ITU called for proposals for IMT-2000 from different interested parties and it received many different ideas based on time division multiple access (TDMA) and code division multiple access (CDMA) technology. The European Telecommunications Standards Institute (ETSI) and Global System for Mobile Communications (GSMC) companies, such as the infrastructure vendors Nokia and Ericsson, are backing wideband code division multiple access (W-CDMA), whilst the US vendors, including Qualcomm and Lucent Technologies, are backing CDMA2000.
To take account of the different vested interests, the ITU has proposed that IMT-2000 is a CDMA-based standard, which encompasses three different modes of operation, each of which should be able to work over both the GSM and IS-41 network architectures. The three modes are as follows:
- Direct sequence frequency division duplex (FDD). Based on the first operational node of the UMTS terrestrial radio access (UTRA) proposal, this mode is supported by the GSM network operators and vendors, plus Japan's ARIB community
- Multi-carrier FDD. Based on the CDMA2000 proposal of the US Telecommunications Industry Association, this mode is supported by the US cellular network operators and vendors
- Time division duplex. Based on the second operational node of the UTRA proposal, this unpaired band solution has been harmonised with China's TD-SCDMA proposal
The green light for the development of these services was given at the ITU's World Radiocommunication Conference, held from 8 May to 3 June 2000 in Istanbul, Turkey. This decision provides for a number of frequency bands available on a global basis for countries wishing to implement IMT-2000. Making use of existing mobile and mobile-satellite frequency allocations, the agreement also provides for a high degree of flexibility, to allow operators to migrate towards IMT-2000 according to market and other national considerations.
At the same time, it does not preclude the use of these bands for other types of mobile applications, or by other services to which these bands are allocated - a key factor that enabled the consensus to be reached. While the decision of the Conference globally provides for the licensing and manufacturing of IMT-2000 in the identified bands on a globally harmonized basis, each country will decide on the timing of availability at the national level according to their specific needs.
The frequencies for IMT-2000 were allocated in two phases, the first made in 1992 when IMT-2000 began development, and the second set at the recent conference. The bands that had initially been identified in 1992, on the basis of which licensing has already been made or is under way in many parts of the world, remained unchanged. Around 100 licenses are expected to be awarded worldwide by the year 2002. These bands are 1885-2025MHz and 2110-2200MHz. The additional bands identified for the terrestrial component of IMT-2000 are: 806-960MHz, 1710-1885MHz and 2500-2690MHz. All bands globally identified for IMT-2000 have equal status.
The only IMT-2000 system that was fully operational in the first quarter of 2002 was NTT DoCoMo's 3G service which went online in October 2001. This runs to the ITU' standards (W-CDMA) and spectrum frequency (1.9-2GHz). Other operators plan to start commercial services by the end of 2002 when handsets become available. These include Telenor Mobile and Netcom in Norway; Sonera and Radiolinja in Finland; and Orange Sverige, Europolitan, Hi3g, and Tele2 in Sweden.
In other areas operators have reported field trials and experiments in W-CDMA across these frequencies. These include: Orange SA in France; Telecom Italia Mobile in Italy; Manx Telecom on the Isle of Man; and Monaco Telecoms in Monaco. Operators in Japan and the Republic of Korea have begun to implement systems on other spectra for a similar time-scale.