In the Americas this is called D-AMPS, or known just as digital cellular. In Europe, GSM is employed as 2G standard. Both GSM and D-AMPS use TDMA multiplexing. Another widely spread 2G standard in the Americas and in Asia is IS-95 also known as CDMA due to the multiplexing technology employed.
2.5G services are already available in many countries and 3G will be widely available in many countries during 2004. Work on 4G has already started although its scope is not clear yet.