Evolution-Data Optimized (EV-DO, EVDO, etc.) is a telecommunications
standard for the wireless transmission of data through radio signals,
typically for broadband Internet access. EV-DO is an evolution of the
CDMA2000 (IS-2000) standard that supports high data rates and can be
deployed alongside a wireless carrier's voice services. It uses
advanced multiplexing techniques including code division multiple
access (CDMA) as well as time division multiplexing (TDM) to maximize
throughput. It is a 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. It is also used
Globalstar satellite phone network.
EV-DO service has been or will be discontinued in much of Canada in
An EV-DO channel has a bandwidth of 1.25 MHz, the same bandwidth
size that IS-95A (IS-95) and
IS-2000 (1xRTT) use. The channel
structure, on the other hand, is very different. Additionally, the
back-end network is entirely packet-based, and thus is not constrained
by the restrictions typically present on a circuit switched network.
The EV-DO feature of
CDMA2000 networks provides access to mobile
devices with forward link air interface speeds of up to 2.4 Mbit/s
with Rel. 0 and up to 3.1 Mbit/s with Rev. A. The reverse link rate
for Rel. 0 can operate up to 153 kbit/s, while Rev. A can operate at
up to 1.8 Mbit/s. It was designed to be operated end-to-end as an IP
based network, and so it can support any application which can operate
on such a network and bit rate constraints.
1 Standard revisions
1.1 EV-DO Rel. 0 (TIA-856 Release 0)
Forward link channel structure
Reverse link structure
1.2 EV-DO Rev. A (TIA-856 Revision A)
1.3 EV-DO Rev. B (TIA-856 Revision B)
1.4 EV-DO Rev. C (TIA-856 Revision C) and TIA-1121
2 See also
3 Notes and references
4 External links
CDMA2000 EV-DO USB wireless modem
HSPA+ EV-DO USB wireless modem from
There have been several revisions of the standard, starting with
Release 0 (Rel. 0). This was later expanded upon with Revision A (Rev.
A) to support
Quality of Service
Quality of Service (to improve latency) and higher rates
on the forward link and reverse link. Later in 2006 Revision B (Rev.
B) was published, that among other features includes the ability to
bundle multiple carriers to achieve even higher rates and lower
latencies (see TIA-856 Rev. B below). The upgrade from EV-DO Rev. A to
EV-DO Rev. B involves a software update to the cell site modem, and
additional equipment for the new EV-DO carriers. Existing cdma2000
operators may also have to retune some of their existing 1xRTT
channels to other frequencies, since Rev. B requires all DO carriers
be within 5 MHz.
EV-DO Rel. 0 (TIA-856 Release 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 down link 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
Telecommunication Union (ITU) under the 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 many of the major
carriers, and is marketed simply as EV-DO. This provides a more
marketing-friendly emphasis that the technology was optimized for
Forward link channel structure
The primary characteristic that differentiates an EV-DO channel from a
1xRTT channel is that it is time multiplexed on the forward link (from
the tower to the mobile). This means that a single mobile has full use
of the forward traffic channel within a particular geographic area (a
sector) during a given slot of time. Using this technique, EV-DO is
able to modulate each user’s time slot independently. This allows
the service of users that are in favorable RF conditions with very
complex modulation techniques while also serving users in poor RF
conditions with simpler and more redundant signals.
The forward channel is divided into slots, each being 1.667 ms long.
In addition to user traffic, overhead channels are interlaced into the
stream. These include the Pilot which helps the mobile find and
identify the channel, the Media Access Channel (MAC) which tells the
mobiles when their data is scheduled, and the Control Channel, which
contains other information that the network needs the mobiles to know.
The modulation to be used to communicate with a given mobile is
determined by the mobile itself. It listens to the traffic on the
channel, and depending on the receive signal strength along with the
perceived multi-path and fading conditions, makes its best guess as to
what data-rate it can sustain while maintaining a reasonable frame
error rate of 1-2%. It then communicates this information back to the
serving sector in the form of an integer between 1 and 12 on the
"Digital Rate Control" (DRC) channel. Alternatively, the mobile can
select a "null" rate (DRC 0), indicating that the mobile either cannot
decode data at any rate, or that it is attempting to hand off to
another serving sector.
The DRC values are as follows:
Data rate (kbit/s)
Payload size (bits)
Another important aspect of the EV-DO forward link channel is the
scheduler. The scheduler most commonly used is called "proportional
fair". It's designed to maximize sector throughput while also
guaranteeing each user a certain minimum level of service. The idea is
to schedule mobiles reporting higher DRC indices more often, with the
hope that those reporting worse conditions will improve in time.
The system also incorporates Incremental Redundancy Hybrid ARQ. Each
sub-packet of a multi-slot transmission is a turbo-coded replica of
the original data bits. This allows mobiles to acknowledge a packet
before all of its sub-sections have been transmitted. For example, if
a mobile transmits a DRC index of 3 and is scheduled to receive data,
it will expect to get data during four time slots. If after decoding
the first slot the mobile is able to determine the entire data packet,
it can send an early acknowledgement back at that time; the remaining
three sub-packets will be cancelled. If however the packet is not
acknowledged, the network will proceed with the transmission of the
remaining parts until all have been transmitted or the packet is
Reverse link structure
The reverse link (from the mobile back to the Base Transceiver
Station) on EV-DO Rel. 0 operates very similar to that of 3G1X CDMA.
The channel includes a reverse link pilot (helps with decoding the
signal) along with the user data channels. Some additional channels
that do not exist in 3G1X include the DRC channel (described above)
and the ACK channel (used for HARQ). Only the reverse link has any
sort of power control, because the forward link is always transmitted
at full power for use by all the mobiles. The reverse link has both
open loop and closed loop power control. In the open loop, the reverse
link transmission power is set based upon the received power on the
forward link. In the closed loop, the reverse link power is adjusted
up or down 800 times a second, as indicated by the serving sector
(similar to 3G1X).
All of the reverse link channels are combined using code division and
transmitted back to the base station using BPSK where they are
decoded. The maximum speed available for user data is 153.2 kbit/s,
but in real-life conditions this is rarely achieved. Typical speeds
achieved are between 20-50 kbit/s.
EV-DO Rev. A (TIA-856 Revision A)
Revision A of EV-DO makes several additions to the protocol while
keeping it completely backwards compatible with Release 0.
These changes included the introduction of several new forward link
data rates that increase the maximum burst rate from 2.45 Mbit/s to
3.1 Mbit/s. Also included were protocols that would decrease
connection establishment time (called enhanced access channel MAC),
the ability for more than one mobile to share the same timeslot
(multi-user packets) and the introduction of QoS flags. All of these
were put in place to allow for low latency, low bit rate
communications such as VoIP.
The additional forward rates for EV-DO Rev. An are:
Data rate in kbit/s
Payload size (bits)
In addition to the changes on the forward link, the reverse link was
enhanced to support higher complexity modulation (and thus higher bit
rates). An optional secondary pilot was added, which is activated by
the mobile when it tries to achieve enhanced data rates. To combat
reverse link congestion and noise rise, the protocol calls for each
mobile to be given an interference allowance which is replenished by
the network when the reverse link conditions allow it. The reverse
link has a maximum rate of 1.8 Mbit/s, but under normal conditions
users experience a rate of approximately 500-1000 kbit/s but with more
latency than cable and dsl.
EV-DO Rev. B (TIA-856 Revision B)
EV-DO Rev. B is a multi-carrier evolution of the Rev. A specification.
It maintains the capabilities of EV-DO Rev. A, and provides the
Higher rates per carrier (up to 4.9 Mbit/s on the downlink per
carrier). Typical deployments are expected to include 2 or 3 carriers
for a peak rate of 14.7 Mbit/s. Higher rates by bundling multiple
channels together enhance the user experience and enable new services
such as high definition video streaming.
Reduced latency by using statistical multiplexing across
channels—enhances the experience for latency sensitive services such
as gaming, video telephony, remote console sessions and web browsing.
Increased talk-time and standby time
Reduced interference from the adjacent sectors especially to users at
the edge of the cell signal which improves the rates that can be
offered by using Hybrid frequency re-use.
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.
EV-DO Rev. C (TIA-856 Revision C) and TIA-1121
Qualcomm early on realized that EV-DO was a stop-gap solution, and
foresaw an upcoming format war between LTE and determined that a new
standard would be needed.
Qualcomm originally called this technology
EV-DV (Evolution Data and Voice). As EV-DO became more pervasive,
EV-DV evolved into EV-DO Rev C.
The EV-DO Rev. C standard was specified by
3GPP2 to improve the
CDMA2000 mobile phone standard for next generation applications and
requirements. It was proposed by
Qualcomm as the natural evolution
CDMA2000 and the specifications were published by 3GPP2
(C.S0084-*) and TIA (TIA-1121) in 2007 and 2008 respectively.
The brand name UMB (Ultra Mobile Broadband) was introduced in 2006 as
a synonym for this standard.
UMB was intended to be a so-called fourth-generation technology. These
technologies use a high bandwidth, low latency, underlying TCP/IP
network with high level services such as voice built on top.
Widespread deployment of 4G networks promises to make applications
that were previously not feasible not only possible but ubiquitous.
Examples of such applications include mobile high definition video
streaming and mobile
Like LTE, the UMB system was to be based upon Internet networking
technologies running over a next generation radio system, with peak
rates of up to 280 Mbit/s. Its designers intended for the system to be
more efficient and capable of providing more services than the
technologies it was intended to replace. To provide compatibility with
the systems it was intended to replace, UMB was to support handoffs
with other technologies including existing
CDMA2000 1X and 1xEV-DO
UMB's use of
OFDMA would have eliminated many of the disadvantages of
CDMA technology used by its predecessor, including the "breathing"
phenomenon, the difficulty of adding capacity via microcells, the
fixed bandwidth sizes that limit the total bandwidth available to
handsets, and the near complete control by one company of the required
While capacity of existing Rel. B networks can be increased 1.5-fold
by using EVRC-B voice codec and QLIC handset interference
cancellation, 1x Advanced and EV-DO Advanced offers up to 4x network
capacity increase using BTS interference cancellation (reverse link
interference cancellation), multi-carrier links, and smart network
In November 2008, Qualcomm, UMB's lead sponsor, announced it was
ending development of the technology, favoring LTE instead. This
followed the announcement that most
CDMA carriers chose to adopt
WiMAX or the competing
3GPP Long Term Evolution
3GPP Long Term Evolution (LTE) standard
as their 4G technology. In fact no carrier had announced plans to
However, during the ongoing development process of the 4G technology,
3GPP added some functionalities to LTE, allowing it to become a sole
upgrade path for all wireless networks.
OFDMA-based air interface
Frequency Division Duplex
Scalable bandwidth between 1.25–20 MHz (
OFDMA systems are
especially well suited for wider bandwidths larger than 5 MHz)
Support of mixed cell sizes, e.g., macro-cellular, micro-cellular
IP network architecture
Support of flat, centralized and mixed topologies
Data speeds over 275 Mbit/s downstream and over 75 Mbit/s upstream
Significantly higher data rates & reduced latencies using Forward
Link (FL) advanced antenna techniques
MIMO, SDMA and Beamforming
Higher Reverse Link (RL) sector capacity with quasi-orthogonal reverse
Increased cell edge user data rates using adaptive interference
Dynamic fractional frequency reuse
Distributed RL power control based on other cell interference
Real time services enabled by fast seamless L1/L2 handoffs
Independent RL & FL handoffs provide better airlink and handoff
Power optimization through use of quick paging and semi-connected
Low-overhead signaling using flexible airlink resource management
Fast access and request using RL
CDMA control channels
New scalable IP architecture supports inter-technology handoffs
New handoff mechanisms support real-time services throughout the
network and across different airlink technologies
Fast acquisition and efficient multi-carrier operation through use of
Multi-carrier configuration supports incremental deployment & mix
of low-complexity & wideband devices
Computer science portal
High-Speed Downlink Packet Access
High-Speed Downlink Packet Access or HSDPA
Mobile broadband modem
List of device bandwidths
Evolution-Data Optimized network equipment suppliers
Simultaneous Voice and EV-DO data (SVDO)
Notes and references
^ Cyrus Farivar. "
Globalstar GSP-1700 satphone also loaded with
EV-DO". Engadget. Retrieved 14 August 2015.
^ "Service Bulletins:
CDMA Network Changes in Canada". MTS. Retrieved
29 May 2015. As of July 1, 2015 EVDO service across Canada (excluding
Manitoba) is being shut down.
^ "3G -
CDMA2000 1xEV-DO Technologies".
CDMA development Group.
Archived from the original on 2007-12-20. Retrieved 2008-01-18.
CDMA2000 1xEV-DO". QUALCOMM Technology and Solutions. Archived from
the original on 2006-11-04.
^ a b c Bi, Qi; S. Vitebsky (17–21 March 2002). "Performance
analysis of 3G-1X EV-DO high data rate system". IEEE Wireless
Communications and Networking Conference. IEEE: 389–395.
^ a b Bi, Qi (March 2004). "A Forward Link Performance Study of the
1xEV-DO Rel. 0 System Using Field Measurements and Simulations" (PDF).
Lucent Technologies. Retrieved 2008-01-18.
^ CDG: Advantages of
CDMA2000 Archived October 23, 2008, at the
^ "RTAP Rate". agilent.com. Retrieved 14 August 2015.
^ Gopal, Thawatt (11–15 March 2007). "EVDO Rev. A Control Channel
Bandwidth Analysis for Paging". IEEE
Wireless Communications and
Networking Conference. IEEE: 3262–7. doi:10.1109/WCNC.2007.601.
^ a b "cdma2000 High Rate Packet Data Air Interface" (PDF). 3GPP2.
July 2005. pp. 10–114. Retrieved 2008-01-18.
^ Jr., Michael F. Oryl. "What is EV-DV? - Definition".
www.mobileburn.com. Retrieved 5 April 2018.
^ "CDG : News & Events : CDG Press Releases".
www.cdg.org. Retrieved 5 April 2018.
^ "Telecommunications Industry Association (TIA) Publishes UMB
Standards Suite". tiaonline.org. 19 March 2008. Retrieved 14 August
^ "CDG : News & Events : CDG Press Releases".
www.cdg.org. Retrieved 5 April 2018.
^ "DO Advanced: Maximizing the Performance of EV-DO". Qualcomm.
October 27, 2011.
^ "1X Advanced – Four-Fold Increase in Voice Capacity Whitepaper".
Qualcomm. May 1, 2009.
Qualcomm halts UMB project, Reuters, November 13th, 2008
CDMA2000 standards and specification documents
CDMA Development Group (CDG)
EVDOforums.com EV-DO discussion group
A video demonstration of EVDO Rev. B capabilities
Spread spectrum in digital communications
Code-division multiple access
Code-division multiple access (CDMA)
Spread spectrum methods
Direct-sequence spread spectrum
Direct-sequence spread spectrum (DSSS)
Frequency-hopping spread spectrum
Frequency-hopping spread spectrum (FHSS)
Chirp spread spectrum
Chirp spread spectrum (CSS)
Time-hopping spread spectrum (THSS)
Space Network (NASA)
Cordless phones: DECT
IS-95 (aka cdmaOne)
CDMA2000 (aka IS-2000)
PN (pseudorandom noise) code
Power spectral density (PSD)
Low probability of intercept
Cellular network standards
List of mobile phone generations
0G (radio telephones)
MTA - MTB - MTC - MTD
AMPS (TIA/EIA/IS-3, ANSI/TIA/EIA-553)
IS-95 and ANSI-J-STD 008)
IS-54 and IS-136)
CDMA2000 1X (TIA/EIA/IS-2000)
CDMA2000 1X Advanced
UTRA-FDD / W-CDMA
UTRA-TDD LCR / TD-SCDMA
UTRA-TDD HCR / TD-CDMA
CDMA2000 1xEV-DO Release 0 (TIA/IS-856)
(3.5G, 3.75G, 3.9G)
CDMA2000 1xEV-DO Revision A (TIA/EIA/IS-856-A)
EV-DO Revision B (TIA/EIA/IS-856-B)
EV-DO Revision C
LTE Advanced (E-UTRA)
LTE Advanced Pro (4.5G Pro/pre-5G/4.9G)
WiMAX (IEEE 802.16m)
WiMax 2.1 (LTE-TDD)
List of standards
Comparison of standards
Channel access methods
Spectral efficiency comparison table
Cellular frequencies (Bands: