2G

2G
Michel Bakni · CC BY-SA 4.0 · source
Name	2G
Introduced	1991
Predecessor	1G
Successor	3G
Standards	GSM, IS-95, TDMA, CDMA
Frequency bands	900 MHz, 1800 MHz, 1900 MHz
Modulation	GMSK, QPSK
Organizations	ETSI, TIA, ITU, GSMA

2G 2G denotes the second generation of cellular mobile telecommunications technology that introduced digital signal processing, subscriber authentication, and new radio access protocols. Developed through collaborations among European Telecommunications Standards Institute engineers, Telecommunications Industry Association members, and mobile operators like Vodafone and Deutsche Telekom, 2G replaced analog systems used by firms such as Motorola and Nokia in the late 1980s. The rollout began with commercial launches by carriers including Radiolinja and Orange S.A., enabling new services and regulatory frameworks in markets from United Kingdom to Japan.

History

The design and deployment of 2G were driven by standards bodies and corporations: ETSI produced the Global System for Mobile communications specification, while Qualcomm promoted IS-95 in North America and NTT DoCoMo advanced packet-oriented research that influenced later generations. Early commercial networks were launched by operators such as Radiolinja in Finland and O2 (UK) subsidiaries, following spectrum allocations from regulators like the Federal Communications Commission and the European Commission. The technology evolved through cooperation among equipment vendors like Ericsson, Siemens, Alcatel-Lucent, and Siemens AG, and handset manufacturers including Nokia, Ericsson Mobile, and Motorola, provoking rapid subscriber growth captured by market analysts at Gartner and IDC.

Technology and standards

2G encompassed multiple competing standards: GSM standardized time-division multiple access with Gaussian minimum-shift keying, while IS-95 (also known as cdmaOne) used code-division multiple access from Qualcomm. Other flavors included D-AMPS and proprietary extensions by firms such as Lucent Technologies. Standardization bodies like ETSI and the Telecommunications Industry Association defined protocol stacks, while international coordination by the International Telecommunication Union allocated spectrum bands such as 900 MHz and 1800 MHz in Europe and 1900 MHz in North America. Later enhancements introduced packet data through General Packet Radio Service and circuit-switched data extensions created by collaborating entities including Ericsson and Nokia Siemens Networks.

Network architecture and operation

A 2G network architecture combined radio access components from vendors like Huawei and Siemens with core switching systems supplied by Alcatel-Lucent and Motorola. Key functional elements included base transceiver stations connected to base station controllers, which interfaced with mobile switching centers and subscriber databases like the Home Location Register managed under specifications by ETSI. Roaming arrangements among operators such as Vodafone Group and T-Mobile International relied on signalling standards developed by organizations including the 3rd Generation Partnership Project precursor groups and billing interconnect agreements overseen by industry associations such as the GSMA.

Services and features

2G introduced digital voice codecs and voice privacy mechanisms developed by research labs at Nokia Research Center and Ericsson Research, along with services like short message service pioneered by carriers such as Vodafone and handset OEMs like Nokia Corporation. Multimedia messaging and early mobile internet access via WAP gateways were promoted by vendors and portal providers including Openwave and content partners like Reuters. Value-added services included caller identification and roaming introduced in commercial packages by operators such as Sprint Corporation and AT&T Inc. in their respective markets.

Deployment and market impact

Global deployment of 2G transformed markets, enabling mass adoption across regions from Europe and North America to Asia and Africa. Operators including China Mobile, Bharti Airtel, and Telefónica leveraged 2G to scale subscriber bases, altering competition patterns documented by analysts at McKinsey & Company and PricewaterhouseCoopers. Handset ecosystems grew around incumbents like Nokia and challengers such as Sony Ericsson, creating supply chains with component suppliers including Qualcomm and Broadcom. Policy and economic consequences prompted actions by institutions like the World Bank and regulators such as the Office of Communications (Ofcom).

Security and privacy issues

2G introduced subscriber authentication and the A3/A8 algorithms for SIM-based security developed by firms like Gemplus and Oberthur Technologies, but also exhibited vulnerabilities. Weaknesses in the A5/1 and A5/2 cipher algorithms, researched by cryptographers at institutions including Bell Labs and universities like University of Cambridge and ETH Zurich, enabled interception risks exploited by researchers and actors using tools traced back to cases involving intelligence services and criminal groups. Signalling System No. 7 interconnects and SS7 vulnerabilities, documented by security labs such as Kaspersky Lab and FireEye, facilitated location tracking and interception in roaming environments coordinated among carriers like Deutsche Telekom and Orange S.A..

Legacy and transition to newer generations

2G laid foundational concepts adopted by subsequent generations, influencing protocols standardized by the 3GPP and spectrum management practices at the International Telecommunication Union. The migration path included overlays and refarming strategies executed by operators such as Verizon Communications and AT&T Inc. to deploy 3G and later 4G LTE, while regulators including the Federal Communications Commission and European Commission coordinated spectrum auctions to repurpose 2G bands. Despite phase-outs by carriers like T-Mobile US and Vodafone Group in certain markets, legacy 2G services persisted in niche applications for machine-to-machine links supported by device manufacturers such as Sierra Wireless and industrial suppliers like Siemens AG.

Category:Mobile telecommunications generations