History of Mobile Phone: Generation

Analog cellular telephony (1G)
The first commercial fully automated cellular network (the 1G generation) was launched in Japan by NTT in 1979. The initial launch network covered the full metropolitan area of Tokyo's over 20 million inhabitants with a cellular network of 23 base stations.
The second launch of 1G networks was the simultaneous launch of the Nordic Mobile Telephone (NMT) system in Denmark, Finland, Norway and Sweden in 1981.
NMT was the first mobile phone network featuring international roaming. The Swedish electrical engineer Östen Mäkitalo started to work on this vision in 1966, and is considered as the father of the NMT system and some consider him also the father of the cellular phone.
The first NMT installations as well as the First AMPS installations were based on the Ericsson AXE digital exchange nodes.

Digital mobile communication (2G)
The first "modern" network technology on digital 2G (second generation) cellular technology was launched by Radiolinja in 1991 in Finland on the GSM standard which also marked the introduction of competition in mobile telecoms when Radiolinja challenged incumbent Telecom Finland who ran a 1G NMT network. The first data services appeared on mobile phones starting with person-to-person SMS text messaging in Finland in 1993. It has a stable call quality and the right of standby time.

Wideband mobile communication (3G)
In 2001 the first commercial launch of 3G (Third Generation) was again in Japan by NTT DoCoMo on the WCDMA standard. The standard 2G CDMA networks became 3G compliant with the adoption of Revision A to EV-DO. Revision A of EV-DO makes several additions to the protocol while keeping it completely backwards compatible with older versions of EV-DO. The beginning of the third-generation mobile phone one of the goals is to develop a universal can ba a wireless communication system.

Reference: http://en.wikipedia.org/wiki/Mobile_phone