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History of AMPS |
The AMPS wireless system was developed by Bell Labs (Research arm of AT&T at that time, but now the research arm of its parent company Lucent Technologies). The AMPS cell phone standard was approved by the FCC, finalised and first used in Chicago in 1983. AMPS later became an official TIA standard in 1986.
AMPS originally operated as an analogue system in the 800 MHz frequency band. However, it has since expanded to TDMA and CDMA digital operation and, more recently into the 1800MHz - 2200MHz PCS frequency band. The best known AMPS systems are in the US and Canada, but AMPS is also a de facto standard throughout Mexico, Central and South America, very common in the Pacific Rim and also found in Africa and the remains of the USSR. In summary, AMPS is on every continent except Europe and Antarctica which use GSM and smoke signals respectively.
The AMPS standard used by the cellular telephone industry since 1981 has a large installed base throughout the world. Because the AMPS specification is well tested and understood, several systems based upon the AMPS model have been developed for both commercial and military use. Furthermore, the AMPS specification is feeling competitive pressures from new standards such as Global System for Mobile Communication (GSM) and from enhancements such as Cellular Digital Packet Data (CDPD).
The AMPS standard established a range of frequencies between 824 megahertz and 894 megahertz for analogue cell phones. In order to encourage competition and keep prices low, this standard established the concept of 2 carriers in every market, known as A and B carriers (e.g. - Sprint and Cellular One). Each carrier is given 832 voice frequencies, each with a bandwidth of 30 kilohertz. A pair of frequencies (one for transmit and one for receive) is used to provide a duplex voice channel per phone.
The transmit and receive frequencies of each voice channel are separated by 45 megahertz. Each carrier also has 21 data channels to use for housekeeping activities like registration, paging, etc.
| Send comments to webmaster Copyright © 1997 Derek Mc Donnell. All Rights Reserved. Last updated 07-Apr-1998. |
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