CDMA 3G Variants (in the IMT-2000 Family)

In this section we cover the following
:: cdma2000
:: cdma2000 1X-EV-DO
:: cdma2000 1X-EV-DV
:: cdma2000 3X

CDMA aficionados are rigorously promoting a technically benign upgrade of existing cdmaOne (IS-95) CDMA networks to faster cdma2000 technology, a CDMA 3G standard that they say can provide the same level of 3G service claimed by W-CDMA/UMTS promoters. There are various types of cdma2000 types, explained below.


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cdma2000 1X
The 1xEV specification was developed by the Third Generation Partnership Project 2 (3GPP2), a partnership consisting of five telecomnunications standards bodies: CWTS in China, ARIB and TTC in Japan, TTA in Korea and TIA in North America.It is also known as High Rate Packet Data Air Interface Specification. It delivers 3G-like services up to 140 kbps peak rate while occupying a very small amount of spectrum (1.25 MHz per carrier), protecting this precious resource for operators.

cdma2000 1X EV-DO
1X EV-DO, also called 1X-EV Phase One, is an enhancement that puts voice and data on separate channels in order to provide data delivery at 2.4Mbit/s. It was developed by the Third Generation Partnership Project 2 (3GPP2), a partnership consisting of five telecomnunications standards bodies. Also known as High Rate Packet Data Air Interface.

cdma2000 1X EV-DV
EV-DV, or 1X-EV Phase Two with promises of data speeds ranging from 3Mbps to 5Mbps. As many as eight proposals have been submitted to standards committee 3GPP2 for the design of EV-DV

cdma2000 3X
CDMA2000 3x is an ITU-approved, IMT-2000 (3G) standard. It is part of what the ITU has termed IMT-2000 CDMA MC. It uses 5 Mhz spectrum (3x 1.25 Mhz channels) to give speeds of around 2-4 Mbps.


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This first phase of cdma2000 - variously called 1XRTT, 3G1X, or just plain 1X - is designed to double current voice capacity and support always-on data transmission speeds 10 times faster than typically available today, some 153.6 kbps on both the forward and reverse links.

Handset standby times also increase by up to 50%. Users will also be able to benefit from enterprise and consumer applications requiring more bandwidth, including personal information management, telemetry, corporate intranet access, video conferencing, gaming and music on demand.

The increase in voice and data capacity stems inter alia from advances in modulation algorithms, new IP backbones, and new chipsets that support up to 32 simultaneous users on a single chip, a four-fold increase over the previous generation.

While the cdma2000 specification allows for an evolutionary migration to later advances in cdma2000 that use core IP networks and voice-over-IP, the current 1X migration requires relatively modest hardware and software upgrades to existing cdmaOne infrastructure. Even then, operators can upgrade to 1X without having to implement it throughout their entire cdmaOne network, which means they can upgrade certain hotspots that require voice capacity enhancements or higher data speeds.

The strategy also aims to reduce technological risks by phased enhancements of networks with medium rate data services, and then later evolve to higher rate data services so as to avoid uncertainties of ROI that currently cloud the UMTS 3G vision.

cdma2000 can be deployed in existing spectrums such as 1900MHz along with an existing cdmaOne system, overlaying its new feature set and increased capacity on the existing cdmaOne networks. Most importantly, it uses existing (and paid for) 1.25 MHz spectrum.

Handsets using cdma2000 technology will also be backward compatible to the existing cdmaOne networks, so current handsets and features will operate over next generation networks providing continued access both at home and while roaming. Operators who deploy 3G with 1X will still have roaming with worldwide CDMA operators on their cdmaOne networks. Dual mode handsets that allow TDMA/cdma2000 interoperability may also augment the business case for a move by TDMA operators to cdma2000.

The flexible migration from cdmaOne provides a series of upgrades leading to cdma2000's increased voice capacity and Megabit 3G data rates, allowing each operator to upgrade when its individual market requirements dictate without significantly upgrading infrastructure or purchasing new spectrum.