# CDMA2000

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Family of 3G mobile technology standards

This article is about the mobile phone technology. For the channel access method, see [Code-division multiple access](/source/Code-division_multiple_access).

[Huawei](/source/Huawei) CDMA2000 [EVDO](/source/EVDO) USB [wireless modem](/source/Wireless_modem) (2009)

**CDMA2000** (also known as **C2K** or **IMT Multi‑Carrier** (**IMT‑MC**)) is a family of [3G](/source/3G)[1] mobile technology standards for sending voice, data, and [signaling](/source/Signaling_(telecommunications)) data between [mobile phones](/source/Mobile_phone) and [cell sites](/source/Cell_site). It is developed by [3GPP2](/source/3GPP2) as a backwards-compatible successor to [second-generation](/source/2G) [cdmaOne](/source/CdmaOne) (IS-95) set of standards and used especially in North America and South Korea.

CDMA2000 compares to [UMTS](/source/UMTS), a competing set of [3G](/source/3G) standards, which is developed by [3GPP](/source/3GPP) 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:

- Voice: CDMA2000 1xRTT, 1X Advanced

- Data: CDMA2000 1xEV-DO ([Evolution-Data Optimized](/source/Evolution-Data_Optimized)): Release 0, Revision A, Revision B, [Ultra Mobile Broadband](/source/Ultra_Mobile_Broadband) (UMB)

All are approved radio interfaces for the [ITU](/source/International_Telecommunication_Union)'s [IMT-2000](/source/IMT-2000). In the United States, *CDMA2000* is a registered trademark of the [Telecommunications Industry Association](/source/Telecommunications_Industry_Association) (TIA-USA).[2]

As of 2025, almost all public CDMA2000 networks have been shut down, usually to be replaced by [LTE](/source/LTE_(telecommunication)) networks.

## 1X

Part of a series on the Wireless network technologies Analog 0G 1G (1.5G) Digital 2G (2.5G, 2.75G, 2.9G) 3G (3.5G, 3.75G, 3.9G/3.95G) 4G (4G/4.5G, 4.5G, 4.9G) 5G (5.5G) 6G Mobile telecommunications v t e

**CDMA2000 1X (IS-2000)**, also known as **1x** and **1xRTT**, is the core CDMA2000 wireless air interface standard. The designation "1x", meaning *1 times radio transmission technology*, indicates the same [radio frequency](/source/Radio_frequency) (RF) bandwidth as [IS-95](/source/IS-95): a [duplex](/source/Duplex_(telecommunications)) pair of 1.25 MHz radio channels. 1xRTT almost doubles the capacity of IS-95 by adding 64 more traffic channels to the [forward link](/source/Forward_link), [orthogonal](/source/Orthogonality) to (in [quadrature](/source/Quadrature_phase) with) the original set of 64. The 1X standard supports packet data speeds of up to 153 [kbit/s](/source/Kilobit_per_second) with real world data transmission averaging 80–100 kbit/s in most commercial applications.[3] IMT-2000 also made changes to the [data link layer](/source/Data_link_layer) for greater use of data services, including medium and link access control protocols and [quality of service](/source/Quality_of_service) (QoS). The IS-95 data link layer only provided [best-effort delivery](/source/Best-effort_delivery) for data and circuit switched channel for voice (i.e., a voice frame once every 20 ms).

## 1xEV-DO

Main article: [Evolution-Data Optimized](/source/Evolution-Data_Optimized)

[BlackBerry](/source/BlackBerry) smartphone displaying '1XEV' as the service status in the upper right corner (2011)

**CDMA2000 1xEV-DO (Evolution-Data Optimized)**, often abbreviated as **EV-DO** or **EV**, is a [telecommunications](/source/Telecommunication) standard for the [wireless](/source/Wireless) transmission of data through [radio](/source/Radio) signals, typically for [broadband Internet access](/source/Broadband_Internet_access). It uses [multiplexing](/source/Multiplexing) techniques including [code-division multiple access](/source/Code-division_multiple_access) (CDMA) as well as [time-division multiple access](/source/Time-division_multiple_access) to maximize both individual user's throughput and the overall system throughput. It is standardized (IS-856) by [3rd Generation Partnership Project 2](/source/3rd_Generation_Partnership_Project_2) (3GPP2) as part of the CDMA2000 family of standards and has been adopted by many [mobile phone](/source/Mobile_phone) service providers around the world – particularly those previously employing CDMA networks.

## 1X Advanced

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]

## Networks

See also: [List of CDMA2000 networks](/source/List_of_CDMA2000_networks)

The CDMA Development Group states that, as of April 2014, there are 314 [operators](/source/Mobile_network_operator) in 118 countries offering CDMA2000 1X and/or 1xEV-DO service.[7][*[needs update](https://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Chronological_items)*]

As of 2025, only very few active networks remain, with most of them being private networks maintained for [machine to machine](/source/Machine_to_machine) communication for specific critical infrastructure.

## Access authentication in CDMA networks

Access authentication in CDMA networks for [telecommunications](/source/Telecommunication) and [computing](/source/Computing) provide network access for a mobile device. Specific methods such as [CAVE-based Authentication](/source/CAVE-based_Authentication) ([IS-95](/source/IS-95)/[1xRTT](/source/1xRTT)), and [A12 Authentication](/source/A12_Authentication) ([1xEV-DO](/source/1xEV-DO)) are possible. The serving network provides the mobile device access authentication mechanism.[8][9] The exact method employed depends upon the type of service being used:

- [CAVE-based Authentication](/source/CAVE-based_Authentication) – Used for access authentication in CDMA/1xRTT

- [AKA](/source/Authentication_and_Key_Agreement) – 3G successor to CAVE-based authentication

- [A12 Authentication](/source/A12_Authentication) – Used for access authentication in 1xEV-DO

[1xEV-DO](/source/1xEV-DO) Hybrid MS/AT devices may employ both CAVE-based and A12 authentication since these devices connect to both the [1xRTT](/source/1xRTT) and [1xEV-DO](/source/1xEV-DO) networks.

## History

This section needs expansion. You can help by adding missing information. (March 2011)

CDMA2000 technology was developed by [Qualcomm](/source/Qualcomm) in the late 1990s as an enhancement to the [cdmaOne](/source/CdmaOne) standard.

The intended [4G](/source/4G) successor to CDMA2000 was [UMB (Ultra Mobile Broadband)](/source/Ultra_Mobile_Broadband); however, in November 2008, Qualcomm announced it was ending development of the technology, favoring [LTE](/source/LTE_(telecommunication)) instead.[10]

In the USA, the last CDMA2000 network was shut down in 2024.[11]

## Patent licensing

In 2007, Qualcomm provided a global patent license for CDMA2000 to the Chinese company [Teleepoch](https://en.wikipedia.org/w/index.php?title=Teleepoch&action=edit&redlink=1).[12]

## See also

- [Channel access method](/source/Channel_access_method)

- [List of authentication protocols](/source/List_of_authentication_protocols)

- [List of CDMA2000 networks](/source/List_of_CDMA2000_networks)

- [Mobile broadband](/source/Mobile_broadband)

## References

1. **[^](#cite_ref-1)** ["What really is a Third Generation (3G) Mobile Technology"](https://web.archive.org/web/20110607105523/http://www.itu.int/ITU-D/imt-2000/DocumentsIMT2000/What_really_3G.pdf) (PDF). International Telecommunication Union. Archived from [the original](http://www.itu.int/ITU-D/imt-2000/DocumentsIMT2000/What_really_3G.pdf) (PDF) on June 7, 2011. Retrieved October 28, 2012.

1. **[^](#cite_ref-2)** [CDMA2000 trademark application](http://tess2.uspto.gov/bin/showfield?f=doc&state=4001:kets67.2.3) [Archived](https://web.archive.org/web/20170113010120/http://tess2.uspto.gov/bin/showfield?f=doc&state=4001:kets67.2.3) January 13, 2017, at the [Wayback Machine](/source/Wayback_Machine), uspto.gov, November 17, 2009

1. **[^](#cite_ref-3)** ["CDG : Technology : CDMA2000 1X"](https://web.archive.org/web/20100802011151/http://www.cdg.org/technology/cdma20001x.asp). *CDMA Development Group*. Archived from [the original](http://www.cdg.org/technology/cdma20001x.asp) on August 2, 2010. Retrieved July 28, 2017.

1. **[^](#cite_ref-4)** ["Evolution of CDMA Roadmap—Voice Perspective"](https://web.archive.org/web/20161005115836/https://www.cdg.org/news/events/webinar/100513_cdma450_operators/2-ALU-Newbury%20450%20Webinar_3.pdf) (PDF). [Alcatel-Lucent](/source/Alcatel-Lucent). May 13, 2010. Archived from [the original](https://www.cdg.org/news/events/webinar/100513_cdma450_operators/2-ALU-Newbury%20450%20Webinar_3.pdf) (PDF) on October 5, 2016. Retrieved May 17, 2016.

1. **[^](#cite_ref-5)** ["Guidelines for using cdma2000 1x Revision E Features on Earlier Revisions"](https://web.archive.org/web/20160705073206/http://www.3gpp2.org/Public_html/specs/C.S0099-0_v2.0_Guidelines%20for%20using%20cdma2000%201x%20Revision%20E%20Features%20on%20Earlier%20Revisions_20110819.pdf) (PDF). [3GPP2](/source/3GPP2). July 2011. Archived from [the original](http://www.3gpp2.org/Public_html/specs/C.S0099-0_v2.0_Guidelines%20for%20using%20cdma2000%201x%20Revision%20E%20Features%20on%20Earlier%20Revisions_20110819.pdf) (PDF) on July 5, 2016. Retrieved May 17, 2016.

1. **[^](#cite_ref-6)** ["1X Advanced"](http://www.qualcomm.com/solutions/wireless-networks/technologies/1x-advanced). [Qualcomm](/source/Qualcomm). [Archived](https://web.archive.org/web/20140712002148/http://www.qualcomm.com/solutions/wireless-networks/technologies/1x-advanced) from the original on July 12, 2014. Retrieved September 18, 2013.

1. **[^](#cite_ref-7)** ["CDG : CDMA Statistics"](https://web.archive.org/web/20180927201826/http://cdg.org/resources/cdma_stats.asp). CDMA Development Group. Archived from [the original](https://www.cdg.org/resources/cdma_stats.asp) on September 27, 2018. Retrieved June 13, 2015.

1. **[^](#cite_ref-8)** Authority Hub-Where Authentication Meets Artistry. ["Unlocking the Secrets of CDMA Subscriber Identity Module"](https://mojoauth.com/ciam-101/cdma-subscriber-identity-module). *Authority Hub - Where Authentication Meets Artistry*. Retrieved October 13, 2025.

1. **[^](#cite_ref-9)** ["CDMA Network Technology: A Decade Of Advances And Challenges"](https://www.tek.com/en/documents/technical-brief/cdma-network-technology-decade-advances-and-challenges). *www.tek.com*. Retrieved October 13, 2025.

1. **[^](#cite_ref-10)** ["Qualcomm halts UMB project, sees no major job cuts"](https://www.reuters.com/article/marketsNews/idUSN1335969420081113?rpc=401&). *Reuters*. November 13, 2008. [Archived](https://web.archive.org/web/20090414175331/http://www.reuters.com/article/marketsNews/idUSN1335969420081113?rpc=401&) from the original on April 14, 2009.

1. **[^](#cite_ref-11)** Zeman, Benjamin (April 26, 2024). ["What the heck happened to CDMA networks?"](https://www.androidpolice.com/what-happened-to-cdma-networks/). *Android Police*. Retrieved September 25, 2025.

1. **[^](#cite_ref-12)** ["Qualcomm gives patent license for CDMA2000 units to Chinese firm"](https://www.reuters.com/article/qualcomm-patent-idUKWNAS497420070927). *Reuters*. September 27, 2007. [Archived](https://web.archive.org/web/20211205160023/https://www.reuters.com/article/qualcomm-patent-idUKWNAS497420070927) from the original on December 5, 2021. Retrieved December 5, 2021.

## External links

- [TIA TR-45 Engineering Committee for CDMA Standards](https://web.archive.org/web/20120829055636/http://www.tiaonline.org/standards/committees/committee.cfm?comm=tr-45)

- [3GPP2](http://www.3gpp2.org/) [Archived](https://web.archive.org/web/20040123013738/http://3gpp2.org/) January 23, 2004, at the [Wayback Machine](/source/Wayback_Machine) Standards and specifications

- [CDMA2000](http://www.radio-electronics.com/info/cellulartelecomms/3gpp2/cdma2000-1xrtt-basics-tutorial.php) Overviews of the CDMA2000 standards - 1X to UMB

- [cdma2000.info](http://cdma2000.info) Online interactive cdma2000 SDU decoder - covers all releases up to C.S0005-F 2.0

v t e Cellular network standards List of mobile phone generations 0G radio telephones (1946) MTS IMTS Altai OLT MTA - MTB - MTC - MTD AMTS Autotel (PALM) ARP B-Netz AMR 1G (1979) AMPS family AMPS - N-AMPS TACS - ETACS Other NMT C-450 Hicap Mobitex DataTAC CT1 RTMI 2G (1991) GSM/3GPP family GSM CSD - HSCSD 3GPP2 family cdmaOne (IS-95) AMPS family D-AMPS (IS-54 and IS-136) Other CDPD iDEN PDC PHS CT2 2G transitional (2.5G, 2.75G, 2.9G) GSM/3GPP family GPRS EDGE/EGPRS - Evolved EDGE 3GPP2 family CDMA2000 1X (TIA/EIA/IS-2000) CDMA2000 1X Advanced Other WiDEN DECT 3G (1998) IMT-2000 (2001) 3GPP family UMTS UTRA-FDD / W-CDMA FOMA UTRA-TDD LCR / TD-SCDMA UTRA-TDD HCR / TD-CDMA 3GPP2 family CDMA2000 1xEV-DO Release 0 (TIA/IS-856) 3G transitional (3.5G, 3.75G, 3.9G) 3GPP family HSPA HSDPA HSUPA HSPA+ DC-HSDPA LTE (E-UTRA) 3GPP2 family CDMA2000 1xEV-DO Revision A (TIA/EIA/IS-856-A) EV-DO Revision B (TIA/EIA/IS-856-B) EV-DO Revision C IEEE family Mobile WiMAX IEEE 802.16e Flash-OFDM iBurst (IEEE 802.20) WiBro ETSI family HiperMAN 4G (2009) IMT Advanced (2013) 3GPP family LTE Advanced (E-UTRA) LTE Advanced Pro (4.5G/4.9G) IEEE family WiMAX (IEEE 802.16m) WiMax 2.1 WiBro 5G (2018) IMT-2020 (2021) 3GPP family 5G NR 5G-Advanced (5.5G) 5G RedCap LTE-M NB-IoT Other DECT-2020 Related articles Cellular networks Mobile telephony History Comparison of standards Channel access methods FDMA OFDMA TDMA STDMA SSMA CDMA SDMA Spectral efficiency comparison table Frequency bands GSM UMTS LTE 5G NR CDMA Mobile broadband Multimedia Broadcast Multicast Service NGMN Alliance Push-to-talk MIMO IMS VoLTE ViLTE VoNR ViNR Wi-Fi Calling Osmocom Telecommunication portal Telephones portal

v t e Spread spectrum in digital communications Main articles Spread spectrum Code-division multiple access (CDMA) History Commercial use More... Spread spectrum methods Direct-sequence spread spectrum (DSSS) Frequency-hopping spread spectrum (FHSS) Chirp spread spectrum (CSS) Time-hopping spread spectrum (THSS) CDMA schemes W-CDMA TD-CDMA TD-SCDMA DS-CDMA FH-CDMA MC-CDMA Major implementations Space Network (NASA) GPS Galileo GLONASS Bluetooth Cordless phones: DECT Cellular EV-DO Mobile IS-95 (aka cdmaOne) CDMA2000 (aka IS-2000) Also Qualcomm Verizon Major concepts PN (pseudorandom noise) code Chip Near–far problem Power spectral density (PSD) Process gain Rake receiver Low probability of intercept See also Digital communication Modulation Statistical multiplexing Waveform

v t e Telecommunications History Beacon Broadcasting Cable protection system Cable TV Communications satellite Computer network Data compression audio DCT image video Digital media Internet video online video platform social media streaming Drums Edholm's law Electrical telegraph Fax Heliographs Hydraulic telegraph Information Age Information revolution Internet Mass media Mobile phone Smartphone Optical telecommunication Optical telegraphy Pager Photophone Prepaid mobile phone Radio Radiotelephone Satellite communications Semaphore Phryctoria Semiconductor device MOSFET transistor Smoke signals Telecommunications history Telautograph Telegraphy Teleprinter (teletype) Telephone history The Telephone Cases Television digital streaming Undersea telegraph line Videotelephony Whistled language Wireless revolution Pioneers Nasir Ahmed Edwin Howard Armstrong Mohamed M. Atalla John Logie Baird Paul Baran John Bardeen Alexander Graham Bell Emile Berliner Tim Berners-Lee Francis Blake Jagadish Chandra Bose Charles Bourseul Walter Houser Brattain Vint Cerf Claude Chappe Yogen Dalal Donald Davies Daniel Davis Jr. Amos Dolbear Thomas Edison Philo Farnsworth Reginald Fessenden Lee de Forest Elisha Gray Oliver Heaviside Robert Hooke Erna Schneider Hoover Harold Hopkins Gardiner Greene Hubbard Bob Kahn Dawon Kahng Charles K. Kao Narinder Singh Kapany Hedy Lamarr Roberto Landell Innocenzo Manzetti Guglielmo Marconi Robert Metcalfe Antonio Meucci Samuel Morse Jun-ichi Nishizawa Charles Grafton Page Radia Perlman Alexander Stepanovich Popov Tivadar Puskás Johann Philipp Reis Claude Shannon Almon Brown Strowger Henry Sutton Charles Sumner Tainter Nikola Tesla Camille Tissot Alfred Vail Thomas A. Watson Charles Wheatstone Vladimir K. Zworykin Internet pioneers Transmission media Coaxial cable Fiber-optic communication optical fiber Free-space optical communication Molecular communication Radio waves wireless Transmission line telecommunication circuit Network topology and switching Bandwidth Links Network switching circuit packet Nodes terminal Telephone exchange Multiplexing Space-division Frequency-division Time-division Polarization-division Orbital angular-momentum Code-division Concepts Communication protocol Computer network Data transmission Store and forward Telecommunications equipment Types of network Cellular network Ethernet ISDN LAN Mobile NGN Public Switched Telephone Radio Television Telex UUCP WAN Wireless network Notable networks ARPANET BITNET CYCLADES FidoNet Internet Internet2 JANET NPL network TANet Toasternet Usenet Locations Africa Americas North South Antarctica Asia Europe Oceania Global telecommunications regulation bodies Telecommunication portal Category Outline Commons

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Adapted from the Wikipedia article [CDMA2000](https://en.wikipedia.org/wiki/CDMA2000) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/CDMA2000?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.