Editing Advanced Mobile Phone System (section)

== Technology ==
AMPS is a first-generation [[Cellular network|cellular]] technology that uses [[frequency-division multiple access|separate frequencies]], or "channels", for each conversation. It therefore required considerable [[bandwidth (signal processing)|bandwidth]] for a large number of users. In general terms, AMPS was very similar to the older "0G" [[Improved Mobile Telephone Service]] it replaced, but used considerably more computing power to select frequencies, hand off conversations to [[PSTN|land 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, without interference, if locations were separated enough. The channels were grouped so a specific set was different of the one used on the cell nearby. 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.<ref name="bell_young">{{ Citation | last = Young | first = W. Rae | date = January 1979 | title = Advanced Mobile Phone Service: Introduction, Background, and Objectives | journal = Bell System Technical Journal | volume = 58 | issue = 1  | pages = 1-14 | url = https://onlinelibrary.wiley.com/doi/abs/10.1002/j.1538-7305.1979.tb02208.x }} (Note: Young was the Bell Labs engineer who invented the hexagonal cell concept.)''</ref><ref name="fluhr_porter">{{ Citation | last = Fluhr | first = Z. C.  | last2 = Porter | first2 = P. T. | date = January 1979 | title = Advanced Mobile Phone Service: Introduction, Background, and Objectives | journal = Bell System Technical Journal | volume = 58 | issue = 1  | pages = 43-69 | url =https://onlinelibrary.wiley.com/doi/abs/10.1002/j.1538-7305.1979.tb02210.x }} ''(Note: Porter was the Bell Labs engineer who proposed that the cell towers be at the corners of the hexagons rather than the centers and have directional antennas that would transmit/receive in 3 directions into 3 adjacent hexagon cells.)''</ref>

AMPS suffered from many weaknesses compared to today's digital technologies. As an analog standard, it was susceptible to static and noise, and there was no protection from 'eavesdropping' using a [[Scanner (radio)|scanner]] or an older TV set that could tune into channels 70–83.<ref>{{cite web |title=Analog Cellphone Calls on UHF Channels of a TV | website=[[YouTube]] |url=https://www.youtube.com/watch?v=JsEgUA4z_SM}}</ref>