Evolution-Data Optimized or Evolution-Data only, abbreviated as EV-DO or EVDO and often EV, is a
telecommunications standard for the wireless
transmission of data through radio signals, typically for broadband Internet access. It employs multiplexing
techniques such as CDMA (Code division multiple access) as well as
Frequency division duplex (FDD) to maximize the amount of data transmitted.
It is standardized by 3rd Generation Partnership Project 2 (3GPP2)
as part of the CDMA2000 family of standards and has been adopted by many mobile phone service providers around the world – particularly those previously employing CDMA networks, as
opposed to GSM networks.
The EV-DO feature of CDMA2000 networks 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.[1]
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 acknowledgment 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.
A video demonstration of EVDO rev B capabilities can be found at [1]
TIA-1121
-
The evolution of CDMA2000 is termed Ultra Mobile Broadband (UMB).
Potential competing standards
Motorola proposed a new system called 1Xtreme as an evolution of CDMA2000, but it was rejected by 3GPP2 standardization body. Later, a competing standard called EV-DV developed
by Qualcomm, Lucent, Nokia, Motorola, etc. in 3GPP2 was proposed as an alternate evolution of CDMA. EV-DV stands for
Evolution-Data and Voice, since the channel structure was backwards compatible with IS-95 and IS-2000 (1xRTT), allowing an
in-band network deployment. (EV-DO requires an overlay network when deployed in mixed
mode.)
At the time, there was much debate on the relative merits of DV and DO. Traditional operators with an existing voice network
preferred deploying DV, since it does not require an overlay. Other design engineers, and newer operators without a 1x voice
network, preferred EV-DO because it did not have to be backward compatible, and so could explore different pilot structures,
reverse link silence periods, improved control channels, etc. And the network cost was lower, since EV-DO uses an
IP network and does not require a SS7
network and complex network switches such as a mobile switching center (MSC). Also, equipment was not available for EV-DV in time
to meet market demands whereas the EV-DO equipment and mobile application-specific integrated circuits (ASIC) were available and tested by the
time the EV-DV standard was completed. As a result, the EV-DV standard was less attractive to operators, and has not been
implemented. Verizon Wireless, then Sprint
Nextel in 2004 and smaller operators in 2005 announced their plans to deploy EV-DO. So in March 2005, Qualcomm suspended
development of EV-DV chipsets, and focused on improving the EV-DO product line.
See also
Network equipment suppliers
The following companies are leading providers of EV-DO infrastructure equipment:
Cellular routers
- cellular router
- WAAV, Inc. is a manufacturer of EVDO and HSDPA routers. WAAV's AirBox X2 can connect to
both networks at once.
References and footnotes
- ^ CDMA2000 1xEV-DO. QUALCOMM Technology and Solutions. Archived from the original on 2007-09-24.
External links
|
Internet access methods |
| Wired: |
Dial-up,
ISDN, DSL,
Cable, Fiber optic, Power-line internet |
| Wireless: |
Wi-Fi,
Bluetooth, DECT,
WiBro, WiMAX, UMTS-TDD,
HSPA, EV-DO, Satellite |
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