Information AboutCdma2000 |
| CATEGORIES ABOUT CDMA2000 | |
| mobile telephony standards | |
| cdma | |
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CDMA2000 is a hybrid 2.5G / 3G protocol of mobile Telecommunications Standard s 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 Phone s and Cell Site s. 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 where Channels are defined with codes ( PN Sequences ). CDMA permits many simultaneous transmitters on the same frequency channel, unlike TDMA (time division multiple access), used in GSM and D-AMPS , and FDMA , used in AMPS ("analog" cellular). Since more phones can be served by fewer cell sites, CDMA-based standards have a significant Economic advantage over TDMA- or FDMA-based standards. 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 also known as '''1x''', '''1xRTT''', and '''IS-2000'''. The designation "1x", meaning "1 times Radio Transmission Technology", indicates the same RF bandwidth as pair of 1.25 MHz radio channels. This contrasts with 3xRTT, which uses channels 3 times as wide (3.75 MHz) channels. 1xRTT almost doubles the capacity of IS-95 by adding 64 more traffic channels to the Forward Link , Orthogonal to (in Quadrature with) the original set of 64. Although capable of higher data rates, most deployments are limited to a peak of 144 kbit/s. IS-2000 also made changes to the Data Link Layer for the greater use of data services, including medium and link access control protocols and QoS . The IS-95 data link layer only provided "best effort delivery" for both voice and data. 1xRTT officially qualifies as 3G technology, but it is considered by some to be a 2.5G (or sometimes 2.75G ) technology. This allows it to be deployed in 2G spectrum in some countries that limit 3G systems to certain bands. CDMA2000 3X CDMA2000 3x or '''EV-DO Rev. B''' 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. In Indonesia , Sampoerna Telekom Indonesia (Ceria) is the major mobile wireless service provider on CDMA2000 1x . The other CDMA2000 providers are fixed wireless (such as Bakrie Telkom, Telkom Flexi, and Indosat's Starone). CDMA2000 EV-DO See Also: 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. COUNTRIES WITH CDMA2000 OPERATORS
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