In 1973 a cellular telephone switching plan was described by Fluhr and Nussbaum, In 1977 a cellular telephone data signaling systemwas described by Hachenburg et al.. In 1979 a U.S. Patent 4,152,647, was issued May 1, 1979 to Charles A. Gladden and Martin H. Parelman, both of Las Vegas, Nevada for an emergency cellular system for rapid deployment in areas where there was no cellular service, and assigned by them to the United States Government.
 First generation: Cellular networks
Main article: 1G
The maintechnological development that distinguished the First Generation mobile phones from the previous generation was the use of multiple cell sites, and the ability to transfer calls from one site to the next as the user travelled between cells during a conversation. The first commercially automated cellular network (the 1G generation) was launched in Japan by NTT in 1979. The initial launch network coveredthe full metropolitan area of Tokyo's over 20 million inhabitants with a cellular network of 23 base stations. Within five years, the NTT network had been expanded to cover the whole population of Japan and became the first nation-wide 1G network.
Analog Motorola DynaTAC 8000X Advanced Mobile Phone System mobile phone as of 1983
The next 1G network to launch was 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 work on this vision in 1966, and is considered to be the father of the NMT system, and by some the father of the cellular phone itself. The NMT installations were based on the Ericsson AXE digitalexchange nodes.
Several other countries also launched 1G networks in the early 1980s including the UK, Mexico and Canada. A two year trial started in 1981 in Baltimore and Washington DC with 150 users and 300 Motorola DynaTAC pre-production phones. This took place on a seven tower cellular network that covered the area. The DC area trial turned into a commercial services in about 1983 with fixedcellular car phones also built by Motorola. They later added the 8000X to their Cellular offerings. A similar trial and commercial launch also took place in Chicago by Ameritech in 1983 using the famous first hand-held mobile phone Motorola DynaTAC.
As mentioned above, in 1982 the FCC approved AT&T's 1971 proposal for Advanced Mobile Phone System (AMPS) and allocated frequencies in the 824–894 MHzband. Analog AMPS was superseded by Digital AMPS in 1990.
In 1984, Bell Labs developed modern commercial cellular technology (based, to a large extent, on the Gladden, Parelman Patent), which employed multiple, centrally controlled base stations (cell sites), each providing service to a small area (a cell). The cell sites would be set up such that cells partially overlapped. In a cellular...