Wireless cellular technology or mobile communications started with first generation mobile phones, popularly known as 1G. It was an analog telecommunications system, introduced in 1979 and continued to mid of the 1980s.
1G mobile communication system was introduced in Japan in 1979 by Nippon Telegraph and Telephone (NTT). Initially, it started in Tokyo and within next five years expanded to cover the whole of Japan.
In 1981, Nordic Mobile Telephone (NMT) was launched in European countries. In 1983, Ameritech launched 1G mobiles in the USA using Motorola mobile phones. Use of mobile communication system was then followed by several countries.
The previous wireless communication technologies were push-to-talk systems and sparsely used wireless phones in military and maritime applications. The main difference between the existing wireless communication systems and 1G was the introduction of cellular technology. Here, land area was divided into small sectors known as cells. Each cell had a base station, which used radio signals and a transceiver for communicating with mobile devices. Bade stations were connected to telephone networks. Frequency modulation techniques were used for voice calls by base stations.
Analog signals were prone to interferences. So the communication was noisy.
Analog systems did not support adequate encryption systems. So, security was a vital issue and tapping could not be controlled.