Advanced Mobile Phone System
Encyclopedia
Analog signal
An analog or analogue signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. It differs from a digital signal in terms of small fluctuations in the signal which are...
mobile phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
system standard developed by Bell Labs
Bell Labs
Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...
, and officially introduced in the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
in 1983, Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
in 1986, and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
in 1987. It was the primary analog
Analog signal
An analog or analogue signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. It differs from a digital signal in terms of small fluctuations in the signal which are...
mobile phone system in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
(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.
Technology
AMPS was a first-generation cellularCellular network
A cellular network is a radio network distributed over land areas called cells, each served by at least one fixed-location transceiver known as a cell site or base station. When joined together these cells provide radio coverage over a wide geographic area...
technology that uses separate frequencies, or "channels", for each conversation (see FDMA
Frequency-division multiple access
Frequency Division Multiple Access or FDMA is a channel access method used in multiple-access protocols as a channelization protocol. FDMA gives users an individual allocation of one or several frequency bands, or channels. It is particularly commonplace in satellite communication. FDMA, like...
). 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
Improved Mobile Telephone Service
The Improved Mobile Telephone Service is a "0G" pre-cellular VHF/UHF radio system that links to the PSTN. IMTS was the radiotelephone equivalent of land dial phone 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 fathered the term "cellular" because of its use of small hexagonal "cells" within a system.
It suffered from some weaknesses when compared to today's digital technologies. Since it was an analog standard, it is very susceptible to static and noise and has no protection from eavesdropping using a scanner
Scanner (radio)
A scanner is a radio receiver that can automatically tune, or scan, two or more discrete frequencies, stopping when it finds a signal on one of them and then continuing to scan other frequencies when the initial transmission ceases....
. In the 1990s, "cloning" was an epidemic that cost the industry millions of dollars. An eavesdropper with specialized equipment could intercept a handset's ESN
Electronic Serial Number
Electronic serial numbers were created by the U.S. Federal Communications Commission to uniquely identify mobile devices, from the days of AMPS in the United States from the early 1980s. The administrative role was taken over by the Telecommunications Industry Association in 1997 and is still...
(Electronic Serial Number) and MIN (Mobile Identification Number, aka the telephone number). An Electronic Serial Number is a packet of data which is sent by the handset to the cellular system for billing purposes, effectively identifying that phone on the network. The system then allows or disallows calls and or features based on its customer file. If an ESN/MIN Pair is intercepted, it could then be cloned onto a different phone and used in other areas for making calls without paying.
The problem became so large that some carriers required the use of a PIN
Personal identification number
A personal identification number is a secret numeric password shared between a user and a system that can be used to authenticate the user to the system. Typically, the user is required to provide a non-confidential user identifier or token and a confidential PIN to gain access to the system...
before making calls. Eventually, the cellular companies initiated a system called RF Fingerprinting, where it could determine subtle differences in the signal of one phone from another and shut down some cloned phones. Some legitimate customers had problems with this though if they made certain changes to their own phone, such as replacing the battery and/or antenna. The Oki 900 was the ultimate tool of cell phone hackers because it could listen in to AMPS phone calls right out of the box with no hardware modifications.
Standards
AMPS was originally standardized by ANSIAmerican National Standards Institute
The American National Standards Institute is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international...
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). AMPS networks have been replaced by digital networks based on standards including Digital AMPS
Digital AMPS
IS-54 and IS-136 are second-generation mobile phone systems, known as Digital AMPS . It was once prevalent throughout the Americas, particularly in the United States and Canada. D-AMPS is considered end-of-life, and existing networks have mostly been replaced by GSM/GPRS or CDMA2000...
, GSM, and CDMA2000
CDMA2000
CDMA2000 is a family of 3G mobile technology standards, which use CDMA channel access, to send voice, data, and signaling data between mobile phones and cell sites. The set of standards includes: CDMA2000 1X, CDMA2000 EV-DO Rev. 0, CDMA2000 EV-DO Rev. A, and CDMA2000 EV-DO Rev. B...
which brought improved security as well as increased capacity. Though cloning is still possible even with digital technologies, the cost of wireless service is so low that the problem has virtually disappeared.
Frequency bands
AMPS cellular service operated in the 800 MHz CellularCellular frequencies
All cellular phone networks worldwide use a portion of the radio frequency spectrum designated as ultra high frequency, or "UHF", for the transmission and reception of their signals. The ultra high frequency band is also shared with television, Wi-Fi and Bluetooth transmission...
FM
Frequency modulation
In telecommunications and signal processing, frequency modulation conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant...
band. For each market area, the United States Federal Communications Commission
Federal Communications Commission
The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...
(FCC) allowed two licensee (networks) known as "A" and "B" carriers. Each carrier within a market uses a specified "block" of frequencies consisting of 21 control channels and 395 voice channels. Originally, the B (wireline) side license was usually owned by the local phone company, and the A (non-wireline) license was given to wireless telephone providers.
At the inception of cellular in 1983, the FCC had granted each carrier within a market 333 channels (666 channels total). By the late 1980s, the cellular industry's subscriber base had grown into the millions across America and it became necessary to add channels for additional capacity. In 1989, the FCC granted carriers an expansion from the current 666 channels to the final 832 (416 per carrier). The additional frequencies were from the band held in reserve for future (inevitable) expansion. These frequencies were immediately adjacent to the existing cellular band. These bands had previously been allocated to UHF TV channels 70–83.
The anatomy of each channel is composed of 2 frequencies
Frequency
Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...
. 416 of these are in the 824–849 MHz range for transmissions from mobile stations to the base stations, paired with 416 frequencies in the 869–894 MHz range for transmissions from base stations to the mobile stations. Each cell site will use a subset of these channels, and must use a different set than neighboring cells to avoid interference. This significantly reduced the number of channels available at each site in real-world systems. Each AMPS channel has a one way bandwidth of 30 kHz, for a total of 60 kHz for each duplex channel.
Laws were passed in the US which prohibited the FCC type acceptance and sale of any receiver which could tune the frequency ranges occupied by analog AMPS cellular services. Though the service is no longer offered, these laws remain in force.
Digital AMPS
Later, many AMPS networks were partially converted to D-AMPS, often referred to as TDMA (though TDMATime division multiple access
Time division multiple access is a channel access method for shared medium networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using its own time slot. This...
is a generic term that applies to many cellular systems). D-AMPS was a digital
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
, 2G
2G
2G is short for second-generation wireless telephone technology. Second generation 2G cellular telecom networks were commercially launched on the GSM standard in Finland by Radiolinja in 1991...
standard used mainly by AT&T Mobility and U.S. Cellular
U.S. Cellular
United States Cellular Corporation, d.b.a. U.S. Cellular , owns and operates the sixth largest wireless telecommunications network in the United States, behind Verizon Wireless, AT&T Mobility, Sprint Nextel, T-Mobile USA, and Metro PCS. , they serve about 6.1 million customers in 126 markets in...
in the United States, Rogers Wireless
Rogers Wireless
Rogers Wireless is a wireless telecommunications provider offering mobile phone and data services throughout Canada using Global System for Mobile Communications and Universal Mobile Telecommunications System technology. It is a wholly owned subsidiary of Rogers Communications...
in Canada, Telcel
Telcel
Telcel is Mexico's largest mobile phone carrier, owned by América Móvil. Founded in 1989 and based in Mexico City, Telcel is the leading provider of wireless communications services in Mexico. As of December 31, 2006, Telcel's cellular network covered more than 63% of the geographical area of...
in Mexico, Vivo S.A. and Telecom Italia Mobile
Telecom Italia Mobile
TIM is Telecom Italia's mobile phone brand, and runs a GSM, EDGE, UMTS and HSDPA network in Italy and Brazil.In Europe, TIM is part of the FreeMove alliance.TIM Peru was sold to América Móvil and rebranded Claro...
(TIM) in Brazil, VimpelCom in Russia, Movilnet in Venezuela. In Latin America, AMPS is no longer offered and has been replaced by GSM and new UMTS networks.
GSM and CDMA2000
AMPS and D-AMPS have now been phased out in favor of either CDMA2000CDMA2000
CDMA2000 is a family of 3G mobile technology standards, which use CDMA channel access, to send voice, data, and signaling data between mobile phones and cell sites. The set of standards includes: CDMA2000 1X, CDMA2000 EV-DO Rev. 0, CDMA2000 EV-DO Rev. A, and CDMA2000 EV-DO Rev. B...
or GSM which allow for higher capacity data transfers for services such as WAP
Wireless Application Protocol
Wireless Application Protocol is a technical standard for accessing information over a mobile wireless network.A WAP browser is a web browser for mobile devices such as mobile phones that uses the protocol.Before the introduction of WAP, mobile service providers had limited opportunities to offer...
, Multimedia Messaging System (MMS), and wireless Internet access. There are some phones capable of supporting AMPS, D-AMPS and GSM all in one phone (using the GAIT
GAIT (wireless)
GAIT is a wireless standard developed in 1999 that allows cross-operation of mobile telephone technologies...
standard).
Analog AMPS being replaced by digital
In 2002, the FCC decided to no longer require A and B carriers to support AMPS service as of February 18, 2008. All AMPS carriers have converted most of their consumer base to a digital standard such as CDMA2000 or GSM and continue to do so at a rapid pace. Digital technologies such as GSM and CDMA2000 support multiple voice calls on the same channel and offer enhanced features such as two-way text messaging and data services.Unlike in the United States, the Canadian Radio-television and Telecommunications Commission (CRTC) and Industry Canada
Industry Canada
Industry Canada is the department of the Government of Canada with responsibility for regional economic development, investment, and innovation/research and development. The department employs 6104 FTEs across Canada....
have not set any requirement for maintaining AMPS service in Canada. Rogers Wireless
Rogers Wireless
Rogers Wireless is a wireless telecommunications provider offering mobile phone and data services throughout Canada using Global System for Mobile Communications and Universal Mobile Telecommunications System technology. It is a wholly owned subsidiary of Rogers Communications...
has dismantled their AMPS (along with IS-136) network; the networks were shut down May 31, 2007. Bell Mobility
Bell Mobility
Bell Mobility is a CDMA and HSPA+ based wireless network and the division of Bell Canada which sells wireless services in Canada...
and Telus Mobility
Telus Mobility
Telus Mobility is a division of Telus Communications which sells wireless services in Canada on its numerous networks. They currently have three different networks based on three different technologies: CDMA and HSPA+ on its mainstream networks, plus iDEN via its Mike division...
, who operated AMPS networks in Canada, announced that they would observe the same timetable as outlined by the FCC in the United States, and as a result would not begin to dismantle their AMPS networks until after February 2008.
OnStar
OnStar
OnStar Corporation is a subsidiary of General Motors that provides subscription-based communications, in-vehicle security, hands free calling, turn-by-turn navigation, and remote diagnostics systems throughout the United States, Canada and China. A similar service is known as ChevyStar in Latin...
relied heavily on North American AMPS service for its subscribers because, when the system was developed, AMPS offered the most comprehensive wireless coverage in the US. In 2006, ADT
ADT Security Services
ADT Security Services, originally American District Telegraph, now also known as simply ADT, is a division of Tyco International and a worldwide supplier of electronic security systems, fire alarm systems, communication systems, and integrated building management systems.-History:There were many...
asked the FCC to extend the AMPS deadline due to many of their alarm systems still using analog technology to communicate with the control centers. Cellular companies who own an A or B license (such as Verizon and Alltel) were required to provide analog service until February 18, 2008. After that point, however, most cellular companies were eager to shut down AMPS and use the remaining channels for digital services. OnStar
OnStar
OnStar Corporation is a subsidiary of General Motors that provides subscription-based communications, in-vehicle security, hands free calling, turn-by-turn navigation, and remote diagnostics systems throughout the United States, Canada and China. A similar service is known as ChevyStar in Latin...
transitioned to digital service with the help of data transport technology developed by Airbiquity, but warned customers who could not be upgraded to digital that their service would permanently expire on January 1, 2008.
Companies that used analog AMPS
- Verizon WirelessVerizon WirelessCellco Partnership, doing business as Verizon Wireless, is one of the largest mobile network operators in the United States. The network has 107.7 million subscribers as of 2011, making it the largest wireless service provider in America....
— Formerly operating an AMPS network, on February 18, 2008, Verizon has discontinued all AMPS service. Now primarily operates on CDMA2000CDMA2000CDMA2000 is a family of 3G mobile technology standards, which use CDMA channel access, to send voice, data, and signaling data between mobile phones and cell sites. The set of standards includes: CDMA2000 1X, CDMA2000 EV-DO Rev. 0, CDMA2000 EV-DO Rev. A, and CDMA2000 EV-DO Rev. B...
technology. - Bell MobilityBell MobilityBell Mobility is a CDMA and HSPA+ based wireless network and the division of Bell Canada which sells wireless services in Canada...
and Telus MobilityTelus MobilityTelus Mobility is a division of Telus Communications which sells wireless services in Canada on its numerous networks. They currently have three different networks based on three different technologies: CDMA and HSPA+ on its mainstream networks, plus iDEN via its Mike division...
operated AMPS networks in Canada, though they have since been overlaid with digital services. Both Bell Mobility and Telus Mobility had announced that they would observe the same shutdown guidelines as in the United States, and decommissioned their AMPS networks in 2008. - AlltelAlltelAlltel Corporation is a wireless service provider, primarily based in the United States. Before an acquisition by Verizon Wireless, it served 34 states. After the merger, Alltel continues to serve six states, mostly in rural areas...
— In 2005 disclosed that only 15% of their total customer base are still using the existing analog network. The company has posted a three phase turn down schedule, which was completed in September 2008. With the recent acquisition of Western Wireless, Alltel now takes the claim of the "largest network in America." The claim was true, oddly enough because of wide analog coverage in rural areas. All Alltel AMPS and D-AMPS service was discontinued in September 2008 - Coastel Offshore Cellular — Operated an AMPS network in the Gulf of Mexico that stretched from south of Corpus Christi, TX to south of Gulf Shores, AL. In 2006 Coastel was the only carrier in the US whose entire customer base was still 100% analog based. In 2007 Coastel was merged with Petrocom and SOLA Communications to form BroadpointBroadpointBroadPoint Communications was a US telecommunications company in the late 1990s offering free long-distance calling supported by advertising, a service the company called "Sponsored Communications." Perry Kamel was founder and CEO of the company, based in Landover, Maryland. Users would sign up...
Inc. and the network was converted to GSM. - Moviline (TelefónicaTelefónicaTelefónica, S.A. is a Spanish broadband and telecommunications provider in Europe and Latin America. Operating globally, it is the third largest provider in the world...
Servicios Uno since 1971, Moviline since 1994) was the analogue service provider for the Spanish operator. Moviline has operated an ETACS 900 (mHz) network in Spain. Since 31 December 2003, the system has been closed to new users, at that time, it covered 100% of the Spanish population, but now some antennas have been given to GSM operators. The Moviline brand has been completely replaced by MovistarMovistarMovistar is a major Spanish mobile phone operator owned by Telefónica Móviles. It operates in Spain and in many Latin American countries. It is the largest carrier in Spain with 22 million customers and 41.58% of market share. Its principal competitor in Latin America is America Movil...
, the digital brand of TelefónicaTelefónicaTelefónica, S.A. is a Spanish broadband and telecommunications provider in Europe and Latin America. Operating globally, it is the third largest provider in the world...
, since 1992. The network was completely converted to GSM and its in all Spanish territory. MovistarMovistarMovistar is a major Spanish mobile phone operator owned by Telefónica Móviles. It operates in Spain and in many Latin American countries. It is the largest carrier in Spain with 22 million customers and 41.58% of market share. Its principal competitor in Latin America is America Movil...
have a 3G network with UMTS technology, and offer services over GSM in places without 3G coverage. - AT&T Mobility - In areas where AT&T Mobility previously had D-AMPS operating on 1900 MHz frequencies, no analog AMPS network existed, and the D-AMPS network on the 1900 MHz frequency was shut down in mid-2007. Service on the remaining 850 MHz AMPS markets was discontinued along with 850 MHz D-AMPS service on February 18, 2008, except in areas where service was provided by Dobson Communications. The Dobson AMPS and TDMA networks were shut down on March 1, 2008.
- Telecom New ZealandTelecom New ZealandTelecom New Zealand is a New Zealand-wide communications service provider , providing fixed line telephone services, a mobile network, an internet service provider , a major ICT provider to NZ businesses , and a wholesale network infrastructure provider to other NZ CSPs...
— Operated an AMPS/TDMA network in New Zealand from 1987 until 2007 throughout the whole country and the network was renowned for its superb coverage, In 2000 Telecom announced that they would discontinue the AMPS network within 5 years (2005) to give customers an opportunity to transition to the CDMA2000 and later 1XRTT technologies that replaced it. They later extended that deadline until 6PM 31March 2007. At approximately 7:15 on March 31, 2007 the AMPS/TDMA network ceased to function. - TelstraTelstraTelstra Corporation Limited is an Australian telecommunications and media company, building and operating telecommunications networks and marketing voice, mobile, internet access and pay television products and services....
(formerly Telecom Australia) - operated an AMPS network in Australia from February 1987 until the end of 2000. As part of the introduction of mobile phone competition in Australia, the Australian government mandated GSM as the new standard for mobile networks, and required that Telstra close the AMPS network by 2000. However, GSM base stations could only serve a limited area. While this was OK for Europe, it meant that GSM could not cover large, sparsely populated rural areas of Australia cost effectively. Telstra deployed a CDMA network, which did not suffer this limitation, and while the AMPS network was closed down at the end of 1999 in the major cities, the closure deadline was extended until the end of 2000 in rural areas to ease the transition to CDMA. The CDMA network has since been replaced by an 850 MHz UMTS networkNext GNext G is a third generation mobile telecommunication network operated by Telstra in Australia.-Background:After a review, Telstra announced a plan to upgrade its ageing networks and systems; which includes a new 3G network to replace the then current CDMA mobile network.-Construction:The network...
. - SaskTelSaskTelSaskatchewan Telecommunications is a provincial Crown Corporation operating under the authority of the Saskatchewan Telecommunications Act. It is the only remaining Crown Corporation in the Canadian telecommunications industry....
- operated an AMPS network in SaskatchewanSaskatchewanSaskatchewan is a prairie province in Canada, which has an area of . Saskatchewan is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, and on the south by the U.S. states of Montana and North Dakota....
, CanadaCanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. It was the third largest AMPS network, by subscribers, in the world at the time of its turndown. It was officially shutdown site by site starting at 00:00 on January 2, 2010 after twenty-one years of service. SaskTelSaskTelSaskatchewan Telecommunications is a provincial Crown Corporation operating under the authority of the Saskatchewan Telecommunications Act. It is the only remaining Crown Corporation in the Canadian telecommunications industry....
continues to run CDMA and UMTS networks.