CDMA2000

CDMA2000 is a hybrid 2.5G / 3G protocol of mobile telecommunications standards that use CDMA, a multiple access scheme for digital radio, to send voice, data, and signalling data (such as a dialed telephone number) between mobile phones and cell sites. CDMA2000 is considered a 2.5G protocol in 1xRTT and a 3G protocol in EVDO.

CDMA (code division multiple access) is a mobile digital radio technology that transmits streams of bits and whose channels are divided using codes (PN sequences). CDMA permits many radios to share the same frequency channel. Unlike TDMA (time division multiple access), a different technique used in GSM and D-AMPS, all radios can be active all the time, because network capacity does not directly limit the number of active radios. Since larger numbers of phones can be served by smaller numbers of cell sites, CDMA-based standards have a significant economic advantage over TDMA-based standards, or the oldest cellular standards that used frequency division multiple access (FDMA).

CDMA2000 has a relatively long technical history, and remains compatible with the older CDMA telephony methods (such as cdmaOne) first developed by Qualcomm, a commercial company, and holder of several key international patents on the technology.

The CDMA2000 standards CDMA2000 1xRTT, CDMA2000 EV-DO, and CDMA2000 EV-DV are approved radio interfaces for the ITU's IMT-2000 standard and a direct successor to 2G CDMA, IS-95 (cdmaOne). CDMA2000 is standardized by 3GPP2.

CDMA2000 is a registered trademark of the Telecommunications Industry Association (TIA-USA) in the United States, not a generic term like CDMA. (This is similar to how TIA has branded their 2G CDMA standard, IS-95, as cdmaOne.)

CDMA2000 is an incompatible competitor of the other major 3G standard UMTS. It is defined to operate at 400 MHz, 800 MHz, 900 MHz, 1700 MHz, 1800 MHz, 1900 MHz, and 2100 MHz.

Below are the different types of CDMA2000, in order of increasing complexity:

CDMA2000 1xRTT

CDMA2000 1xRTT, the core CDMA2000 wireless air interface standard, is known by many terms: 1x, 1xRTT, or IS-2000. The designation "1xRTT" (1 times Radio Transmission Technology) is used to identify the version of CDMA2000 radio technology that operates in a pair of 1.25 MHz radio channels (one times 1.25 MHz, as opposed to three times 1.25 MHz in 3xRTT). 1xRTT almost doubles voice capacity over IS-95 networks. Although capable of higher data rates, most deployments have limited the peak data rate to 144 kbit/s. While 1xRTT officially qualifies as 3G technology, 1xRTT is considered by some to be a 2.5G (or sometimes 2.75G) technology. This has allowed it to be deployed in 2G spectrum in some countries which limit 3G systems to certain bands.

The main differences between IS-95 and IS-2000 signaling are: 64 more traffic channels on the forward link that are orthogonal to the original set. Some changes were also made to the data link layer to accommodate the greater use of data services—IS-2000 has media and link access control protocols and QoS control. In IS-95, none of these were present, and the data link layer basically consisted of "best effort delivery" (which is still used for voice).

Countries with CDMA2000 operators

In the United States, Verizon Wireless, Sprint PCS, Alltel, MetroPCS, Cellular South, U.S. Cellular, Cellcom, and Cricket Communications (from Leap Wireless) use 1x, also it is in use in Canada by SaskTel, Manitoba Telecom Services, Bell Mobility, Aliant, and TELUS Mobility, and in Mexico by Iusacell and Unefon.

In Kenya, CDMA2000 1x is available in Nairobi through Telcom Kenya, Flashcom LTD, and E.M. Communications Ltd., which is branded as "popote" in Kenya.

In Sri Lanka there are 5 CDMA operators. Sri Lanka Telecom (SLT) [www.slt.lk] is the largest CDMA service supplier and SLT has very stable EVDO Rev. 0 network and all island covered 1x data service.

Suntel [www.suntel.lk] and Lanka Bell [www.lankabell.com] are providing their service to Sri Lankan customers.They are using 800 MHz range to service in Sri Lanka. Both operators have islandwide 1x data service and these days trying to enter EVDO rev0 data market.

DBN and Tritel are excepting to enter Sri Lanka CDMA market this June with 450 MHz frequency.

In People's Republic of China, China Unicom is the major mobile wireless service provider on CDMA2000 1x. In Nepal, Nepal Telecom and United Telecom Limited are providing the services to customers on CDMA2000 1x.

In India, BSNL, Reliance Communications and Tata Teleservices are major wireless services providers on CDMA2000 1x.

In Indonesia, Mobile-8 is the major mobile wireless service provider on CDMA2000 1x (with EVDO in Western Java). The other CDMA providers are fixed wireless (such as Bakrie Telkom, Telkom Flexi, and Indosat's Starone).

In Brazil, VIVO is the only provider for CDMA 1x.

In Bangladesh, Pacific Telecom's CityCell is CDMA2000 1x RTT provider.

In Venezuela, Movilnet and movistar are the country's wireless services providers on CDMA2000 1x.

In Pakistan, PTCL , World Call ,GoCdma provides CDMA connections..

In Morocco, Wana has recently launched a CDMA2000 service.

In Moldova Unite offers both mobile and fixed telephony and data services using CDMA2000 since March 2007.

In South Africa, Neotel has been awarded 800 mHz Spectrum by icasa and will launch CDMA2000 services later this year.

In Ukraine PEOPLEnet is the only provider for CDMA2000 1x since 2007 year.

In Latvia Triatel offers mobile and fixed telephony and data services using CDMA2000.

In New Zealand Telecom is the only CDMA2000 network, operating both 1x and EVDO Rev 0 nationwide

In Estonia the first CDMA2000 1x network operating in 450 mHz spectrum is available since July 2007 by Eesti Energia subsidiary Televõrk AS by name Kõu, covering all of country territory.

In Russia, [1] is CDMA 1x and EV-DO operator.

CDMA2000 3x

CDMA2000 3x utilizes a pair of 3.75 MHz radio channels (i.e., 3 X 1.25 MHz) to achieve higher data rates. The 3x version of CDMA2000 is sometimes referred to as Multi-Carrier or MC. The 3x version of CDMA2000 has not been deployed and is not under development at present.

CDMA2000 EV-DO

Main article: Evolution-Data Optimized

CDMA2000 EV-DV

CDMA2000 EV-DV (Evolution-Data/Voice), supports downlink (forward link) data rates up to 3.1 Mbit/s and uplink (reverse link) data rates of up to 1.8 Mbit/s. EV-DV can also support concurrent operation of legacy 1x voice users, 1x data users, and high speed EV-DV data users within the same radio channel.

In 2005, Qualcomm put the development of EV-DV on an indefinite halt, due to lack of carrier interest, mostly because both Verizon Wireless and Sprint are using EV-DO.

See also

• PN Sequences
• List of device bandwidths

External links

• 3GPP2 Standards and specifications
• CDMA Development Group (CDG)
• TIA Standards documentation
• Market statistics from the 'CDMA development group' industry consortium