The radio interface for UMTS

At the end of January 1998, ETSI/SMG reached a decision on the technology for the radio interface for UMTS (the Third Generation Wireless standard for Europe, and the ETSI proposal for the ITU IMT 2000 radio interface). This completes the first stage of the development of the UMTS radio access network, which required a year of intensive technical work by most of the major players in GSM. The second stage is to elaborate the full specification of the radio interface and submit this as a candidate to ITU/R for IMT 2000. The technical work on the definition of the UMTS radio interface started in earnest in December 1996 with a SMG 2 workshop, when presentations were made about potential technologies. It was clear that several alternatives appeared to be viable, and there was no consensus as to which of them would best meet the requirements of UMTS. It was therefore decided that the proposals which shared the same underlying technology would be grouped into five concept groups for further study. These proposals are based on wideband CDMA (W-CDMA), OFDMA (orthogonal frequency division multiple access), wideband TDMA, TDMA with spreading (WB TDMA/CDMA or TD/CDMA), and opportunity driven multiple access