Mobile Telephone System

Topics: Mobile phone, GSM, Cellular network Pages: 5 (1398 words) Published: March 9, 2013
Mobile Telephone System
* First generation (1G) analog cellular network
* 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.
1G (or 1-G) refers to the first-generation of wireless telephone technology, mobile telecommunications. These are the analog telecommunications standards that were introduced in the 1980s. The main difference between two succeeding mobile telephone systems, 1G and 2G, is that the radio signals that 1G networks use are analog, while 2G networks are digital. 1G standards

* NMT (Nordic Mobile Telephone)
- Switzerland
- Netherlands
- Eastern Europe
- Russia
* AMPS (Advanced Mobile Phone System)
- Northern Amera
- Australia
* TACS (Total Access Communications System)
- United Kingdom
-Western Germany
- Portugal
- South Africa

NMT (Nordic Mobile Telephone)
* is the first fully automatic cellular phone system. NMT is based on analog technology (first generation or 1G) and two variants exist: NMT-450 and NMT-900. The numbers indicate the frequency bands uses. NMT-900 was introduced in 1986 because it carries more channels than the previous NMT-450 network. * The cell sizes in an NMT network range from 2 km to 30 km. NMT used full duplex transmission, allowing for simultaneous receiving and transmission of voice. * A disadvantage of the original NMT specification is that voice traffic was not encrypted, therefore it was possible to listen to calls using e.g. a scanner. Advanced Mobile Telephone Systems (AMPS)

* is an analog mobile phone system standard developed by Bell Labs, and officially introduced in the Americas in 1978, Israel in 1986, and Australia in 1987. It was the primary analog mobile phone system in North America (and other locales) through the 1980s and into the 2000s. As of February 18, 2008, carriers in the United States were no longer required to support AMPS and companies such as AT&T and Verizon have discontinued this service permanently. AMPS was discontinued in Australia in September 2000. *  Dr. Martin Cooper, developed portable cellular telephony, and Mitchell was among the Motorola employees granted a patent for this work in 1973 * AMPS is a first-generation cellular technology that uses separate frequencies, or "channels", for each conversation. It therefore required considerable bandwidth for a large number of users. In general terms, AMPS was very similar to the older "0G" Improved Mobile Telephone Service, but used considerably more computing power in order to select frequencies, hand off conversations to PSTN lines, and handle billing and call setup. * What really separated AMPS from older systems is the "back end" call setup functionality. In AMPS, the cell centers could flexibly assign channels to handsets based on signal strength, allowing the same frequency to be re-used in various locations without interference. This allowed a larger number of phones to be supported over a geographical area. AMPS pioneers coined the term "cellular" because of its use of small hexagonal "cells" within a system. * AMPS was originally standardized by ANSI as EIA/TIA/IS-3. EIA/TIA/IS-3 was superseded by EIA/TIA-553 and TIA interim standard IS-91 (Narrowband Advanced Mobile Phone System) Total Access Communication System (TACS)

* Total Access Communication System (TACS) and ETACS are mostly-obsolete variants of AMPS which were used in some European countries (including the UK & Ireland in 1983). TACS was also used in Japan under the name Japanese Total Access Communication (JTAC). It was also used in Hong Kong. ETACS was an extended version of TACS with more channels. Second Generation (Digital Cellular Networks)

* Or 2G, it is short for second-generation wireless telephone technology. Second generation 2G cellular telecom networks were commercially launched on the GSM standard in...
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