CDMA2000 is a 3G mobile telecommunications standard, one of the approved radio interfaces for the ITU's IMT-2000 standard, and a successor to 2G CDMA (IS-95, branded cdmaOne). The underlying signaling standard is known as IS-2000. CDMA2000 is an incompatible competitor of the other major 3G standard W-CDMA.

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

There are many different types of CDMA2000. In order of increasing complexity:

CDMA2000 1x

CDMA2000 1x, also known as 3G1X or sometimes 1xRTT, is the core 3G CDMA2000 technology. The designation 1x is used to identify the version of CDMA2000 radio technology that operates in one pair of 1.25 MHz radio channels.

Confusingly, Japanese operator KDDI uses the brand "CDMA 1X WIN" for their CDMA2000 1xEV-DO network.

CDMA2000 1xRTT

CDMA2000 1xRTT (Radio Transmission Technology) is the basic layer of CDMA2000, which supports up to 144 kbit/s packet data speeds. While 1xRTT officially qualifies as 3G technology, 1xRTT is considered by most to be a 2.5G (or sometimes 2.75G) technology as it is several times slower than other 3G technologies. It also doubles voice capacity over previous CDMA networks.

CDMA2000 1xEV

CDMA2000 1xEV (Evolution) is CDMA2000 1x with High Data Rate (HDR) capability added. 1xEV is commonly separated into two phases:

Phase 1 of CDMA2000 1xEV, CDMA2000 1xEV-DO (Evolution-Data Only) supports downlink (Forward Link) data rates up to 3.1 Mbit/s and Up Link (Reverse Link) rates up to 1.8 Mbps in a radio channel dedicated to carrying high speed packet data.

Phase 2 of CDMA2000 1xEV, CDMA2000 1xEV-DV (Evolution-Data and Voice), supports downlink (Forward Link) data rates up to 3.1 Mbit/s and Up Link (Reverse Link) rates of up to 1.8 Mbits/s. 1xEV-DV can also support concurrent operation of legacy 1x voice users, 1xRTT data users, and high speed 1xEV-DV data users within the same radio channel.

1xEV-DO is commercially deployed around the world. In January 2004, Verizon Wireless in North America announced its intention to deploy 1xEV-DO nationally.

As of July 2004, there are no commercial deployments of 1xEV-DV, although some carriers are carrying out testing and limited trials. American carrier Sprint PCS has announced plans to deploy a 1xEV-DV network on top of their existing CDMA network. However, due to delays in the availability of 1xEV-DV equipment and competitive pressures from other American networks deploying 3G networks, Sprint announced, in June 2004, its intention to broadly deploy 1xEV-DO. Sprint's longterm 1xEV-DV plans seem uncertain.

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.

External links

• Radio-Electronics.Com (http://www.radio-electronics.com/info/cellulartelecomms/evdo/ev-do.php)Article on CDMA20001xEV-DO