This was followed in 1981 by the simultaneous launch of the Nordic Mobile Telephone (NMT) system in Denmark, Finland, Norway and Sweden.Several other countries then followed in the early to mid-1980s.
A handheld mobile radio telephone service was envisioned in the early stages of radio engineering.
In 1917, Finnish inventor Eric Tigerstedt filed a patent for a "pocket-size folding telephone with a very thin carbon microphone".
Early predecessors of cellular phones included analog radio communications from ships and trains.
The race to create truly portable telephone devices began after World War II, with developments taking place in many countries.
The advances in mobile telephony have been traced in successive "generations", starting with the early "0G" (zeroth generation) services, such as Bell System's Mobile Telephone Service and its successor, the Improved Mobile Telephone Service.
These "0G" systems were not cellular, supported few simultaneous calls, and were very expensive.The first handheld mobile cell phone was demonstrated by Motorola in 1973.The first commercial automated cellular network was launched in Japan by Nippon Telegraph and Telephone in 1979.A mobile phone is a portable telephone that can make and receive calls over a radio frequency carrier while the user is moving within a telephone service area.The radio frequency link establishes a connection to the switching systems of a mobile phone operator, which provides access to the public switched telephone network (PSTN).Most modern mobile telephone services use a cellular network architecture, and therefore mobile telephones are often also called cellular telephones or cell phones.