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Evolution Data Optimized (EV-DO) is a high-speed mobile data standard which allows cell phone users to download websites, images, music, and multimedia over the airwaves.
It was originally developed by chipmaker, Qualcomm, as part of the CDMA2000 3G cellular broadband standard, and is currently available in the U.S., Canada, and several other markets around the world.
Most EV-DO services currently offer downstream bandwidth of up to 2.4576 Mbps. A new version of the technology known as EV-DO Revision A is currently being rolled out in many parts of the United States, where it will boost both downstream and upstream data transfer rates.
The EV-DO feature of CDMA2000 networks is significantly faster than the Enhanced Data Rates for GSM Evolution (EDGE) used by GSM networks. It provides access to mobile devices with air interface speeds of up to 2.4 Mbit/s with Rev. 0 and up to 3.1 Mbit/s with Rev. A. High-Speed Downlink Packet Access (HSDPA), a competing technology for Wideband Code Division Multiple Access (W-CDMA), along with the new Qualcomm Rev A modems have the ability to maintain both circuit switched voice and packet data calls from the same radio; this functionality is not available in Qualcomm Rev. 0 chipsets. It provides an IP based network.
There have been several revisions of the standard, named alphabetically starting with the first as Rev. A ("revision A") while the first standard is referred to simply as Rev. 0.
TIA-856 Rev 0
The initial design of EV-DO was developed by Qualcomm in 1999 to meet IMT-2000 requirements for a greater-than-2-Mbit/s downlink for stationary communications, as opposed to mobile communication such as a moving cellular phone. Initially, the standard was called High Data Rate (HDR), but was renamed to 1xEV-DO after it was ratified by the International Telecommunication Union (ITU); it was given the numerical designation TIA-856. Originally, 1xEV-DO stood for "1x Evolution-Data Only", referring to its being a direct evolution of the 1x (1xRTT) air interface standard, with its channels carrying only data traffic. The title of the 1xEV-DO standard document is "cdma2000 High Rate Packet Data Air Interface Specification", as cdma2000 (lowercase) is another name for the 1x standard, numerically designated as TIA-2000.
Later, likely due to the possible negative connotations of the word "only", the "DO" part of the standard's name 1xEV-DO was changed to stand for "Data Optimized". So EV-DO now stands for "Evolution-Data Optimized", the 1x prefix has been dropped by the many major carriers, and is marketed simply as EV-DO. This provides a more marketing-friendly emphasis that the technology was optimized for data transfers.
TIA-856 Rev A
Rev. A offers fast packet establishment on both the forward and reverse links along with air interface enhancements that reduce latency and improve data rates. In addition to the increase in the maximum burst downlink rate from 2.45 Mbit/s to 3.1 Mbit/s, Rev. A has a significant improvement in the maximum uplink data rate, from 153 kbit/s to a maximum uplink burst rate of 1.8 Mbit/s. This improvement assumes early acknowledgement of the first subpacket, typical data rates therefore average below 1 Mbit/s.
TIA-856 Rev B
EV-DO Rev B is a multi-carrier evolution of the Rev A specification. It maintains the capabilities of EVDO Rev A, and provides the following enhancements:
- Higher rates per carrier (up to 4.9 Mbit/s on the downlink per carrier). Typical deployments are expected to include 3 carriers for a peak rate of 14.7 Mbit/s
- Higher rates by bundling multiple channels together enhances user experience and enables new services such as high definition video streaming.
- Uses statistical multiplexing across channels to further reduce latency, enhancing the experience for latency-sensitive services such as gaming, video telephony, remote console sessions and web browsing.
- Increased talk-time and standby time.
- Hybrid frequency re-use which reduces the interference from the adjacent sectors and improves the rates that can be offered, especially to users at the edge of the cell.
- Efficient support for services that have asymmetric download and upload requirements (i.e. different data rates required in each direction) such as file transfers, web browsing, and broadband multimedia content delivery.
TIA-1121
The evolution of cdma2000 is termed Ultra Mobile Broadband (UMB).
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