History Of Mobile Phones

The history of mobile phones charts the development of devices which connect wirelessly to the public switched telephone network. The transmission of speech by radio has a longand varied history going back to Reginald Fessenden's invention and shore-to-ship demonstration of radio telephony, through the Second World War with military use of radio telephonylinks. Hand-held radio transceivers have been available since the 1940s. Mobile telephones for automobiles became available from some telephone companies in the 1940s. Earlydevices were bulky and consumed high power and the network supported only a few simultaneous conversations. Modern cellular networks allow automatic and pervasive use of mobile phonesfor voice and data communications.
In the United States, engineers from Bell Labs began work on a system to allow mobile users to place and receive telephone calls from automobiles,leading to inaguation of mobile service on June 17, 1946 in St. Louis, Missouri. Shortly after, AT&T offered Mobile Telephone Service. A wide range of mostly incompatiblemobile telephone services offered limited coverage area and only a few available channels in urban areas. The introduction of cellular technology, which allowed re-use of frequenciesmany times in small adjacent areas covered by relatively low powered transmitters, made widespread adoption of mobile telephones economically feasible.
The advances in mobiletelephony can be traced in successive generations from the early "0G" services like MTS and it's successor Improved Mobile Telephone Service, to first generation (1G) analog cellularnetwork, second generation (2G) digital cellular networks, third generation (3G) broadband data services to the current state of the art, fourth generation (4G) native-IP networks.