The introduction of cells for mobile phone base stations, invented in 1947 by Bell Labs engineers at AT&T, was further industrialized by Bell Labs during the 1960s. Due to their low establishment expenses and fast exploitation, mobile phone networks have since spread hastily throughout the world, outstripping the growth of fixed telephony.
The zero generation (0G) of mobile telephones was introduced in 1945. 0G mobile telephones, such as Mobile Telephone Service, were not officially categorized as mobile phones, since they did not sustain the automatic change of channel frequency during calls, which allows the user to shift from one cell (the base station coverage area) to another cell, an attribute called "handover".
The first marketable cellular network was launched in Japan by NTT in 1979. Fully automatic cellular networks were first introduced in the beginning to mid 1980s (the 1G generation) with the Nordic Mobile Telephone (NMT) system in 1981. This was followed by an explosion in mobile telephone habit, particularly in Northern Europe.
The first "modern" network technology on digital 2G (second generation) cellular technology was launched by Radiolinja (now part of Elisa Group) in 1991 in Finland on the GSM standard which also striking the beginning of competition in mobile telecoms when Radiolinja challenged current Telecom Finland (now part of TeliaSonera) who ran a 1G NMT network. A decade after, the first commercial commence of 3G (Third Generation) was again in Japan by NTT DoCoMo on the WCDMA standard. However, Martin Cooper, a Motorola engineer, is accredited with the innovation of the modern mobile phone in the 1990s. Until the early 1990s, most mobile phones were too large to be carried in a jacket pocket, so they were normally installed in vehicles as car phones. With the miniaturization of digital apparatus, mobile phones have become more and handier over the years.