Nov 16, 2010

Century of violence and mobile phone part 5

Handheld cell phone
Two 1991 GSM mobile phones with several AC adapters
Martin Cooper, a Motorola researcher and executive, made the first analogue mobile phone call on a prototype model in 1973. There was a long race between Motorola and Bell Labs to produce the first such portable mobile phone. Cooper is the first inventor named on "Radio telephone system" filed on October 17, 1973 with the US Patent Office and later issued as US Patent 3,906,166.
Other named contributors on the patent included Cooper's boss, John F. Mitchell, Motorola's chief of portable communication products, who successfully pushed Motorola to develop wireless communication products that would be small enough to use outside the home, office or automobile and he participated in the design of the cellular phone.
Using a heavy prototype mobile phone, Cooper made the first handheld cellular phone call on April 3, 1973 to Dr. Joel S. Engel of Bell Labs
First generation: Cellular networks

The technological 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 covered the 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.

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 digital exchange 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 fixed cellular 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 MHz band.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 system, a signal between a base station (cell site) and a terminal (phone) only need be strong enough to reach between the two, so different base stations could operate using the same frequencies with little or no interference.
Vodafone made the UK's first mobile call at a few minutes past midnight on 1 January 1985.
The technology in these early networks was pushed to the limit to accommodate increasing usage. The base stations and the mobile phones utilised variable transmission power, which allowed range and cell size to vary. As the system expanded and neared capacity, the ability to reduce transmission power allowed new cells to be added, resulting in more, smaller cells and thus more capacity. The evidence of this growth can still be seen in the many older, tall cell site towers with no antennae on the upper parts of their towers. These sites originally created large cells, and so had their antennae mounted atop high towers; the towers were designed so that as the system expanded—and cell sizes shrank—the antennae could be lowered on their original masts to reduce range.

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