Wednesday, December 2, 2009

A History of Cellular Telephone Development

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Now a days cellular communication has become a part of human life the trends of mobile communication is as follows

1920s - 1940s

Research on frequency characteristics at Bell Labs

Edwin H. Armstrong invents frequency modulation in 1935.

Motorola develops the world's first hand-held portable two-way radio system, the Handie-Talkie.

AT&T introduces a mobile radiotelephone service in St. Louis in 1946. Calling is manual (operator invoked) and is half-duplex (i.e., requires that users "push to talk.").

1947

The cellular concept "materializes from nowhere" at Bell Labs. The use of low powered transmitters in cells permits greater capacity since frequencies can be reused in non-adjacent cells without cross-talk audio interference. The smaller the cells, the more often frequencies can be reused. Handoff is required when mobile units move between cells.

The FCC approves citizens' band radio (CB) service. The rapid expansion of this service and the demand for hand-held CB radio units fueled the development of portable radio units.

1950s

The FCC declines to allocate significant frequencies for mobile radio.

Bell Labs Scientists & Engineers continue low level of investigation into the cellular concept and publish a number of internal papers.

1960s

The FCC denies new spectrum for mobile radio, but convenes the "Advisory Committee for Land Mobile Radio Services" to examine the congestion in land mobile telephony.

AT&T "dusts off" cellular concept and begins serious work on it again.

AT&T develops mobile telephone service for the Amtrak Metroliner. It was a primitive forerunner of today's cellular systems, in which calls were handed off from base to base as the train progressed, triggered by sensors along the tracks.

The FCC opens Docket 18262 (known as the "Cellular Docket")

1970s

The FCC reallocates 115 MHz in the upper portion of the TV UHF band and sets aside new frequencies (64 MHz) for "land mobile communication." A decade of legal disputes over who gets what ensues.

The FCC authorizes AT&T to test the cellular concept in real urban conditions in Newark and Philadelphia.

Patent 3663762, MOBILE COMMUNICATION SYSTEM, applied for by Bell Labs.

Bell Labs files its classic "High-Capacity Mobile Telephone System Feasibility Studies and System Plan" report to the FCC. The report covered not only the technology of a cellular system, but service features, coverage, capacity growth, customer opinions on quality, and costs as well.

Bell Labs develops a microprocessor- based handoff system with fully digital switching. Low-cost frequency synthesizers are also developed.

The FCC grants experimental licenses and decides to authorize construction of two developmental systems: one in Chicago (licensed to Illinois Bell) and a second serving Baltimore, Md. and Washington, DC (licensed to American Radio Telephone Service Inc. (ARTS), now Cellular One, in partnership with Motorola).

The first commercial cellular system is installed in Tokyo by NTT in 1979.

1980s

The Nordic countries introduce a mobile phone system similar to AMPS in 1981.

The FCC adopts rules creating a commercial cellular radio telephone service.

On October 13, 1983, the pilot commercial cellular system of Illinois Bell begins operating in Chicago. The second pilot system run by ARTS in partnership with Motorola begins operation in Baltimore/Washingto n on December 16, 1983.

By 1984, Washington, DC has two competing cellular providers,

By 1988, many cellular systems (particularly New York and Los Angeles) are already becoming overloaded as the promise of nearly infinite expansion of capacity from cell splitting turns out to be more costly and difficult than foreseen.

1990s

Cellular construction permits have been issued for at least one system in every market in the United States.

1992

Cellular Subscriber count tops 10 million.

1994

Bell Labs engineers Joel Engel and Richard Frenkiel win National Medal of Technology for their work in cellular telephony.

Irwin Jacobs, CEO of Qualcomm, wins the National Medal of Technology for Qualcomm's development of CDMA.

1995

Cellular Subscriber count tops 25 million.

The PCS frequency bands are approved by the FCC(Federal communication Commission)
, launching new competitors to existing cellular systems.

1997

Cellular Subscriber count tops 50 million
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