UMTS StandardsW-CDMA is not the only standard suitable for the transmission rates and handoff’s, there are also competing access technologies such as CDMA2000, and other systems such as wCDMA-TDD, aka IPWireless. Flarion, and Arraycom’s iBurst. Although these systems exist, UMTS is expected to dominate these standards and become the global recognised standard for 3G.
That being said, IMT-2000 – the standard for the family of standards of 3G (as said so by the ITU), also counts EDGE – Enhanced Data Rates for Global Evolution, and TD-SCDMA from China, as well as W-CDMA, and CDMA2000.
As CDMA2000 is an easy upgrade from cdmaOne, therefore does not require new frequency allocation, it can operate in existing PCS spectrums. Existing GSM operators will most likely adopt UMTS, but because of the very high cost of obtaining new the new spectrum licences, and equipment, most will take a back seat to see how UMTS pans out before in use.
EDGE has being adopted in the USA, providers such as AT&T have taken EDGE as a temporary solution, Cingular and T-Mobile USA also plans to launch EDGE. EDGE is a short term upgrade for the GSM system, as it uses existing GSM frequency spectrum, it is compatible with current handsets.