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CDMA2000 (also known asC2K orIMT Multi‑Carrier (IMT‑MC)) is a family of3G[1] mobile technology standards for sending voice, data, andsignaling data betweenmobile phones andcell sites. It is developed by3GPP2 as a backwards-compatible successor tosecond-generationcdmaOne (IS-95) set of standards and used especially in North America and South Korea.
CDMA2000 compares toUMTS, a competing set of3G standards, which is developed by3GPP and used in Europe, Japan, China, and Singapore.
The name CDMA2000 denotes a family of standards that represent the successive, evolutionary stages of the underlying technology. These are:
All are approved radio interfaces for theITU'sIMT-2000. In the United States,CDMA2000 is a registered trademark of theTelecommunications Industry Association (TIA-USA).[2]
As of 2025, almost all public CDMA2000 networks have been shut down, usually to be replaced byLTE networks.
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CDMA2000 1X (IS-2000), also known as1x and1xRTT, is the core CDMA2000 wireless air interface standard. The designation "1x", meaning1 times radio transmission technology, indicates the sameradio frequency (RF) bandwidth asIS-95: aduplex pair of 1.25 MHz radio channels. 1xRTT almost doubles the capacity of IS-95 by adding 64 more traffic channels to theforward link,orthogonal to (inquadrature with) the original set of 64. The 1X standard supports packet data speeds of up to 153 kbit/s with real world data transmission averaging 80–100 kbit/s in most commercial applications.[3] IMT-2000 also made changes to thedata link layer for greater use of data services, including medium and link access control protocols andquality of service (QoS). The IS-95 data link layer only providedbest-effort delivery for data and circuit switched channel for voice (i.e., a voice frame once every 20 ms).
CDMA2000 1xEV-DO (Evolution-Data Optimized), often abbreviated asEV-DO orEV, is atelecommunications standard for thewireless transmission of data throughradio signals, typically forbroadband Internet access. It usesmultiplexing techniques includingcode-division multiple access (CDMA) as well astime-division multiple access to maximize both individual user's throughput and the overall system throughput. It is standardized (IS-856) by3rd Generation Partnership Project 2 (3GPP2) as part of the CDMA2000 family of standards and has been adopted by manymobile phone service providers around the world – particularly those previously employing CDMA networks.
1X Advanced (Rev.E)[4][5] is the evolution of CDMA2000 1X. It provides up to four times the capacity and 70% more coverage compared to 1X.[6]
The CDMA Development Group states that, as of April 2014, there are 314operators in 118 countries offering CDMA2000 1X and/or 1xEV-DO service.[7][needs update]
As of 2025, only very few active networks remain, with most of them being private networks maintained formachine to machine communication for specific critical infrastructure.
Access authentication in CDMA networks fortelecommunications andcomputing provide network access for a mobile device. Specific methods such asCAVE-based Authentication (IS-95/1xRTT), andA12 Authentication (1xEV-DO) are possible. The serving network provides the mobile device access authentication mechanism.[8][9][10] The exact method employed depends upon the type of service being used:
1xEV-DO Hybrid MS/AT devices may employ both CAVE-based and A12 authentication since these devices connect to both the1xRTT and1xEV-DO networks.
CDMA2000 technology was developed byQualcomm in the late 1990s as an enhancement to the CDMA standard. The intended4G successor to CDMA2000 wasUMB (Ultra Mobile Broadband); however, in November 2008,Qualcomm announced it was ending development of the technology, favoringLTE instead.[11] In the USA, the last CDMA2000 network was shut down in 2024[12].
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In 2007, Qualcomm provided a global patent license for CDMA2000 to the Chinese company Teleepoch.[13]
Cellular network standards | |||||||||
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| 0Gradio telephones (1946) | |||||||||
| 1G (1979) |
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| 2G (1991) |
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| 2G transitional (2.5G, 2.75G, 2.9G) |
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| 3G (1998) IMT-2000 (2001) |
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| 3G transitional (3.5G, 3.75G, 3.9G) |
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| 4G (2009) IMT Advanced (2013) |
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| 5G (2018) IMT-2020 (2021) |
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