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2G refers to the second-generation of
cellular network A cellular network or mobile network is a telecommunications network where the link to and from end nodes is wireless network, wireless and the network is distributed over land areas called ''cells'', each served by at least one fixed-locatio ...
technology, which were rolled out globally starting in the early 1990s. The main differentiator to previous mobile telephone systems, retrospectively dubbed 1G, is that the radio signals of 2G networks are
digital Digital usually refers to something using discrete digits, often binary digits. Businesses *Digital bank, a form of financial institution *Digital Equipment Corporation (DEC) or Digital, a computer company *Digital Research (DR or DRI), a software ...
rather than
analog Analog or analogue may refer to: Computing and electronics * Analog signal, in which information is encoded in a continuous variable ** Analog device, an apparatus that operates on analog signals *** Analog electronics, circuits which use analog ...
, for communication between
mobile devices A mobile device or handheld device is a computer small enough to hold and operate in hand. Mobile devices are typically battery-powered and possess a flat-panel display and one or more built-in input devices, such as a touchscreen or keypad. Mod ...
and
base stations Base station (or base radio station, BS) is – according to the International Telecommunication Union's (ITU) Radio Regulations (RR) – a " land station in the land mobile service." A base station is called '' node B'' in 3G, '' eNB'' in LT ...
. In addition to voice telephony, 2G also made possible the use of
data Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted for ...
services. The most common 2G technology has been the
GSM The Global System for Mobile Communications (GSM) is a family of standards to describe the protocols for second-generation (2G) digital cellular networks, as used by mobile devices such as mobile phones and Mobile broadband modem, mobile broadba ...
standard, which became the first globally adopted framework for
mobile communications Mobile may refer to: Places * Mobile, Alabama, a U.S. port city * Mobile County, Alabama * Mobile, Arizona, a small town near Phoenix, U.S. * Mobile, Newfoundland and Labrador Arts, entertainment, and media Music Groups and labels * Mobil ...
. Other 2G technologies include
cdmaOne cdmaOne, most often simply referred to as CDMA, is a 2G digital cellular technology. It was the commercial name for Interim Standard 95 (IS-95), a technology that was developed by Qualcomm and later adopted as a standard by the Telecommunica ...
and the now-discontinued
Digital AMPS Digital AMPS (D-AMPS), most often referred to as TDMA, is a second-generation ( 2G) cellular phone system that was once prevalent throughout the Americas, particularly in the United States and Canada since the first commercial network was deploy ...
(D-AMPS/TDMA), as well the
Personal Digital Cellular Personal Digital Cellular (PDC) was a 2G mobile telecommunications standard used exclusively in Japan. After a peak of nearly 80 million subscribers to PDC, it had 46 million subscribers in December 2005, and was slowly phased out in favor of 3 ...
(PDC) and
Personal Handy-phone System The Personal Handy-phone System (PHS), also known as the Personal Communication Telephone (PCT) in Thailand, and the Personal Access System (PAS) and commercially branded as ''Xiaolingtong'' () in China, was a mobile network system operating in t ...
(PHS) in Japan. The transition to digital technology enabled the implementation of
encryption In Cryptography law, cryptography, encryption (more specifically, Code, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the inf ...
for voice calls and data transmission, significantly improving the security of mobile communications while also increasing capacity and efficiency compared to earlier analog systems. 2G networks were primarily designed to support voice calls and Short Message Service (
SMS Short Message Service, commonly abbreviated as SMS, is a text messaging service component of most telephone, Internet and mobile device systems. It uses standardized communication protocols that let mobile phones exchange short text messages, t ...
), with later advancements such as General Packet Radio Service (
GPRS General Packet Radio Service (GPRS), also called 2.5G, is a mobile data standard on the 2G cellular communication network's Global System for Mobile Communications, global system for mobile communications (GSM). Networks and mobile devices wit ...
) enabling always-on packet data services, including
email Electronic mail (usually shortened to email; alternatively hyphenated e-mail) is a method of transmitting and receiving Digital media, digital messages using electronics, electronic devices over a computer network. It was conceived in the ...
and limited
internet access Internet access is a facility or service that provides connectivity for a computer, a computer network, or other network device to the Internet, and for individuals or organizations to access or use applications such as email and the World Wide ...
. 2G was succeeded by 3G technology, which provided higher data transfer rates and expanded mobile internet capabilities.


History

In 1990, AT&T Bell Labs engineers
Jesse Russell Jesse Eugene Russell (born April 26, 1948) is an American inventor. He was trained as an electrical engineer at Tennessee State University and Stanford University, and worked in the field of wireless communication for over 20 years. He holds pat ...
, Farhad Barzegar and Can A. Eryaman filed a patent for a digital mobile phone that supports the transmission of digital data. Their patent was cited several years later by
Nokia Nokia Corporation is a Finnish multinational corporation, multinational telecommunications industry, telecommunications, technology company, information technology, and consumer electronics corporation, originally established as a pulp mill in 1 ...
and
Motorola Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois. It was founded by brothers Paul and Joseph Galvin in 1928 and had been named Motorola since 1947. Many of Motorola's products had been ...
when they were developing 2G digital mobile phones. 2G was first commercially launched in 1991 by
Radiolinja Radiolinja was a Finnish GSM operator founded on September 19, 1988. On March 27, 1991, the world's first GSM phone call was made on Radiolinja's network. The network was opened for commercial use on July 1, 1991. Radiolinja's slogan was ''So tha ...
(now part of
Elisa Oyj Corporation (natively ) is a Finnish telecommunications company founded in 1882. It was called HPY () until July 2000. The mobile operations of Elisa were previously known as Radiolinja. Elisa is a telecommunications, ICT and online service ...
) in Finland in the form of
GSM The Global System for Mobile Communications (GSM) is a family of standards to describe the protocols for second-generation (2G) digital cellular networks, as used by mobile devices such as mobile phones and Mobile broadband modem, mobile broadba ...
, which was defined by the
European Telecommunications Standards Institute The European Telecommunications Standards Institute (ETSI) is an independent, not-for-profit, standardization organization operating in the field of information and communications. ETSI supports the development and testing of global technical ...
(ETSI). The
Telecommunications Industry Association The Telecommunications Industry Association (TIA) is accredited by the American National Standards Institute (ANSI) to develop voluntary, consensus-based industry standards for a wide variety of information and communication technology (Informat ...
(TIA) defined the
cdmaOne cdmaOne, most often simply referred to as CDMA, is a 2G digital cellular technology. It was the commercial name for Interim Standard 95 (IS-95), a technology that was developed by Qualcomm and later adopted as a standard by the Telecommunica ...
(IS-95) 2G standard, with an eight to ten fold increase in voice call capacity compared to analog AMPS. The first deployment of cdmaOne was in 1995. In North America,
Digital AMPS Digital AMPS (D-AMPS), most often referred to as TDMA, is a second-generation ( 2G) cellular phone system that was once prevalent throughout the Americas, particularly in the United States and Canada since the first commercial network was deploy ...
(IS-54 and IS-136) and
cdmaOne cdmaOne, most often simply referred to as CDMA, is a 2G digital cellular technology. It was the commercial name for Interim Standard 95 (IS-95), a technology that was developed by Qualcomm and later adopted as a standard by the Telecommunica ...
(IS-95) were dominant, but GSM was also used. Later 2G releases in the GSM space, often referred to as 2.5G and 2.75G, include General Packet Radio Service (
GPRS General Packet Radio Service (GPRS), also called 2.5G, is a mobile data standard on the 2G cellular communication network's Global System for Mobile Communications, global system for mobile communications (GSM). Networks and mobile devices wit ...
) and Enhanced Data Rates for GSM Evolution (
EDGE Edge or EDGE may refer to: Technology Computing * Edge computing, a network load-balancing system * Edge device, an entry point to a computer network * Adobe Edge, a graphical development application * Microsoft Edge, a web browser developed by ...
). GPRS allows 2G networks to achieve a theoretical maximum transfer speed of 40 kbit/s (5 kB/s). EDGE increases this capacity, providing a theoretical maximum transfer speed of 384 kbit/s (48 kB/s). Three primary benefits of 2G networks over their 1G predecessors were: * Digitally encrypted phone conversations, at least between the
mobile phone A mobile phone or cell phone is a portable telephone that allows users to make and receive calls over a radio frequency link while moving within a designated telephone service area, unlike fixed-location phones ( landline phones). This rad ...
and the
cellular base station A cell site, cell phone tower, cell base tower, or cellular base station is a cellular frequencies, cellular-enabled mobile device site where antenna (electronics), antennas and electronic communications equipment are placed (typically on a Rad ...
but not necessarily in the rest of the network. * Significantly more efficient use of the radio frequency spectrum enabling more users per frequency band. * Data services for mobile, starting with
SMS Short Message Service, commonly abbreviated as SMS, is a text messaging service component of most telephone, Internet and mobile device systems. It uses standardized communication protocols that let mobile phones exchange short text messages, t ...
text messages then expanding to
Multimedia Messaging Service Multimedia Messaging Service (MMS) is a standard way to send messages that include multimedia content to and from a mobile phone over a cellular network. Users and providers may refer to such a message as a PXT, a picture message, or a multimedia ...
(MMS).


Evolution of GSM 2G


2.5G (GPRS)

2.5G ("second-and-a-half generation") refers to 2G systems that incorporate a
packet-switched In telecommunications, packet switching is a method of grouping data into short messages in fixed format, i.e. '' packets,'' that are transmitted over a digital network. Packets consist of a header and a payload. Data in the header is used b ...
domain alongside the existing
circuit-switched Circuit switching is a method of implementing a telecommunications network in which two network nodes establish a dedicated communications channel ( circuit) through the network before the nodes may communicate. The circuit guarantees the full ...
domain, most commonly implemented through General Packet Radio Service (
GPRS General Packet Radio Service (GPRS), also called 2.5G, is a mobile data standard on the 2G cellular communication network's Global System for Mobile Communications, global system for mobile communications (GSM). Networks and mobile devices wit ...
). GPRS enables packet-based data transmission by dynamically allocating multiple timeslots to users, improving network efficiency. However, this does not inherently provide faster speeds, as similar techniques, such as timeslot bundling, are also employed in circuit-switched data services like High-Speed Circuit-Switched Data (
HSCSD In communications, Circuit Switched Data (CSD) (also named GSM data) is the original form of data transmission developed for the time-division multiple access (TDMA)-based mobile phone systems like Global System for Mobile Communications (GSM). ...
). Within GPRS-enabled 2G systems, the theoretical maximum
transfer rate In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction w ...
is 40 kbit/s (5 kB/s).


2.75G (EDGE)

2.75G refers to the evolution of GPRS networks into
EDGE Edge or EDGE may refer to: Technology Computing * Edge computing, a network load-balancing system * Edge device, an entry point to a computer network * Adobe Edge, a graphical development application * Microsoft Edge, a web browser developed by ...
(Enhanced Data Rates for GSM Evolution) networks, achieved through the introduction of 8PSK (8 Phase Shift Keying) encoding. While the symbol rate remained constant at 270.833 samples per second, the use of 8PSK allowed each symbol to carry three bits instead of one, significantly increasing data transmission efficiency. Enhanced Data Rates for GSM Evolution (EDGE), also known as Enhanced GPRS (EGPRS) or IMT Single Carrier (IMT-SC), is a backward-compatible digital mobile phone technology built as an extension to standard GSM. First deployed in 2003 by AT&T in the United States, EDGE offers a theoretical maximum transfer speed of 384 kbit/s (48 kB/s).


2.875G (EDGE Evolution)

Evolved EDGE (also known as EDGE Evolution or 2.875G) is an enhancement of the EDGE mobile technology that was introduced as a late-stage upgrade to 2G networks. While EDGE was first deployed in the early 2000s as part of GSM networks, Evolved EDGE was launched much later, coinciding with the widespread adoption of 3G technologies such as
HSPA HSPA may refer to: * High Speed Packet Access, a mobile broadband technology * Hawaiian Sugar Planters' Association Education * High School Proficiency Assessment * Humphrey School of Public Affairs, an American public policy school * Hunter Sch ...
and just before the emergence of 4G networks. This timing limited its practical application. Evolved EDGE increased data throughput and reduced latencies (down to 80 ms) by utilizing improved modulation techniques, dual carrier support, dual antennas, and turbo codes. It achieved peak data rates of up to 1 Mbit/s, significantly enhancing network efficiency for operators that had not yet transitioned to 3G or 4G infrastructures. However, despite its technical improvements, Evolved EDGE was never widely deployed. By the time it became available, most network operators were focused on implementing more advanced technologies like
UMTS The Universal Mobile Telecommunications System (UMTS) is a 3G mobile cellular system for networks based on the GSM standard. UMTS uses Wideband Code Division Multiple Access, wideband code-division multiple access (W-CDMA) radio access technolog ...
and
LTE LTE may refer to: Science and technology * LTE (telecommunication) (Long-Term Evolution), a mobile telephony standard ** LTE Advanced, an enhancement ** LTE Advanced Pro, a further enhancement * Compaq LTE, a line of laptop computers * Leukotrie ...
. As of 2016, no commercial networks were reported to support Evolved EDGE.


Phase-out

2G, understood as
GSM The Global System for Mobile Communications (GSM) is a family of standards to describe the protocols for second-generation (2G) digital cellular networks, as used by mobile devices such as mobile phones and Mobile broadband modem, mobile broadba ...
and
CdmaOne cdmaOne, most often simply referred to as CDMA, is a 2G digital cellular technology. It was the commercial name for Interim Standard 95 (IS-95), a technology that was developed by Qualcomm and later adopted as a standard by the Telecommunica ...
, has been superseded by newer technologies such as 3G (
UMTS The Universal Mobile Telecommunications System (UMTS) is a 3G mobile cellular system for networks based on the GSM standard. UMTS uses Wideband Code Division Multiple Access, wideband code-division multiple access (W-CDMA) radio access technolog ...
/
CDMA2000 CDMA2000 (also known as C2K or IMT Multi‑Carrier (IMT‑MC)) is a family of 3G mobile technology standards for sending voice, data, and signaling data between mobile phones and cell sites. It is developed by 3GPP2 as a backwards-compatib ...
), 4G (
LTE LTE may refer to: Science and technology * LTE (telecommunication) (Long-Term Evolution), a mobile telephony standard ** LTE Advanced, an enhancement ** LTE Advanced Pro, a further enhancement * Compaq LTE, a line of laptop computers * Leukotrie ...
/
WiMAX Worldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide physical layer (PHY) and media access control (MAC) options. The WiMA ...
) and 5G (
5G NR 5G NR (5G New Radio) is a radio access technology (RAT) developed by the 3rd Generation Partnership Project (3GPP) for the 5G (fifth generation) mobile network. It was designed to be the global standard for the air interface of 5G networks. It is ...
). However, 2G networks were still available in most parts of the world, while notably excluding the majority of carriers in
North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
,
East Asia East Asia is a geocultural region of Asia. It includes China, Japan, Mongolia, North Korea, South Korea, and Taiwan, plus two special administrative regions of China, Hong Kong and Macau. The economies of Economy of China, China, Economy of Ja ...
, and
Australasia Australasia is a subregion of Oceania, comprising Australia, New Zealand (overlapping with Polynesia), and sometimes including New Guinea and surrounding islands (overlapping with Melanesia). The term is used in a number of different context ...
. Many modern LTE-enabled devices have the ability to fall back to 2G for phone calls, necessary especially in rural areas where later generations have not yet been implemented. In some places, its successor 3G is being shut down rather than 2G –
Vodafone Vodafone Group Public Limited Company () is a British Multinational company, multinational telecommunications company. Its registered office and global headquarters are in Newbury, Berkshire, England. It predominantly operates Service (economic ...
previously announced that it had switched off 3G across Europe in 2020 but still retains 2G as a fallback service. In the US
T-Mobile T-Mobile is the brand of telecommunications by Deutsche Telekom Deutsche Telekom AG (, ; often just Telekom, DTAG or DT; stylised as ·T·) is a partially state-owned German telecommunications company headquartered in Bonn and the largest telec ...
shut down their 3G services while retaining their 2G GSM network. Various carriers have made announcements that 2G technology in the United States, Japan, Australia, and other countries are in the process of being shut down, or have already shut down 2G services so that carriers can re-use the frequencies for newer technologies (e.g. 4G, 5G). As a legacy protocol, 2G connectivity is considered insecure. Specifically, there exist well known methods to attack weaknesses in GSM since 2009 with practical use in crime. Attack routes on 2G CdmaOne were found later and remain less publicized. Android 12 and later provide a network setting to disable 2G connectivity for the device.
iOS Ios, Io or Nio (, ; ; locally Nios, Νιός) is a Greek island in the Cyclades group in the Aegean Sea. Ios is a hilly island with cliffs down to the sea on most sides. It is situated halfway between Naxos and Santorini. It is about long an ...
16 and later can disable 2G connectivity by enabling Lockdown Mode.


Criticism

In some parts of the world, including the United Kingdom, 2G remains widely used for older
feature phone Feature may refer to: Computing * Feature recognition, could be a hole, pocket, or notch * Feature (computer vision), could be an edge, corner or blob * Feature (machine learning), in statistics: individual measurable properties of the phenome ...
s and for
internet of things Internet of things (IoT) describes devices with sensors, processing ability, software and other technologies that connect and exchange data with other devices and systems over the Internet or other communication networks. The IoT encompasse ...
(IoT) devices such as smart meters, eCall systems and vehicle trackers to avoid the high patent licensing cost of newer technologies. Terminating 2G services could leave vulnerable people who rely on 2G infrastructure unable to communicate even with emergency contacts, causing harm and possibly deaths.


Past 2G networks


See also

*
Cliff effect In telecommunications, the (digital) cliff effect or brick-wall effect is a sudden loss of digital signal reception. Unlike analog signals, which gradually fade when signal strength decreases or electromagnetic interference or multipath inc ...
* Dropout *
List of mobile phone generations __NOTOC__ This is a list of generations of wireless network technologies in mobile telecommunications. ''*'' latest and optimal iteration of technology ''**'' originally not considered 4G, only after a revision of 4G specification 0G 0G sys ...
*
Mobile radio telephone Mobile radio telephone systems were mobile telephony systems that preceded modern cellular network technology. Since they were the predecessors of the first generation of cellular telephones, these systems are sometimes retroactively referred to ...
, also known as ''0G'' * 1G * 3G * 4G * 5G * 6G *
Wireless device radiation and health The antennas contained in mobile phones, including smartphones, emit radiofrequency (RF) radiation ( non-ionizing "radio waves" such as microwaves); the parts of the head or body nearest to the antenna can absorb this energy and convert it t ...


References

{{Mobile phones Mobile telecommunications Software-defined radio Wireless communication systems