![Kyocera EVDO router](https://upload.wikimedia.org/wikipedia/commons/2/22/Kyocera_EVDO_router.jpg)
Evolution-Data Optimized (EV-DO, EVDO, etc.) is a
telecommunication
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...
s standard for the
wireless
Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most ...
transmission of data through
radio
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...
signals, typically for
broadband Internet access. EV-DO is an evolution of the
CDMA2000
CDMA2000 (also known as C2K or IMT Multi‑Carrier (IMT‑MC)) is a family of 3G mobile technology standards for sending voice, data, and signaling data between mobile phones and cell sites. It is developed by 3GPP2 as a backwards-compatible ...
(
IS-2000
CDMA2000 (also known as C2K or IMT Multi‑Carrier (IMT‑MC)) is a family of 3G mobile technology standards for sending voice, data, and signaling data between mobile phones and cell sites. It is developed by 3GPP2 as a backwards-compatible ...
) standard which supports high data rates and can be deployed alongside a wireless carrier's voice services. It uses advanced
multiplexing
In telecommunications and computer networking, multiplexing (sometimes contracted to muxing) is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource - a ...
techniques including
code-division multiple access
Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communicatio ...
(CDMA) as well as
time-division multiplexing
Time-division multiplexing (TDM) is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fracti ...
(TDM) to maximize throughput. It is a part of the
CDMA2000
CDMA2000 (also known as C2K or IMT Multi‑Carrier (IMT‑MC)) is a family of 3G mobile technology standards for sending voice, data, and signaling data between mobile phones and cell sites. It is developed by 3GPP2 as a backwards-compatible ...
family of standards and has been adopted by many
mobile phone
A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ...
service providers around the world particularly those previously employing
CDMA
Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communicatio ...
networks. It is also used on the
Globalstar
Globalstar, Inc. is an American satellite communications company that operates a low Earth orbit (LEO) satellite constellation for satellite phone and low-speed data communications. The Globalstar second-generation constellation consists of 24 lo ...
satellite phone network.
EV-DO service was discontinued in much of Canada in 2015.
An EV-DO channel has a bandwidth of 1.25 MHz, the same bandwidth size that IS-95A (
IS-95
Interim Standard 95 (IS-95) was the first ever CDMA-based digital cellular technology. It was developed by Qualcomm and later adopted as a standard by the Telecommunications Industry Association in TIA/EIA/IS-95 release published in 1995. The ...
) and IS-2000 (
1xRTT) use,
though the channel structure is very different. The back-end network is entirely
packet-based, and is not constrained by restrictions typically present on a
circuit switched
Circuit switching is a method of implementing a telecommunications network in which two network nodes establish a dedicated communications channel ( circuit) through the network before the nodes may communicate. The circuit guarantees the full ...
network.
The EV-DO feature of CDMA2000 networks provides access to mobile devices with
forward link
In a telecommunications network, a link is a communication channel that connects two or more devices for the purpose of data transmission. The link may be a dedicated physical link or a virtual circuit that uses one or more physical links or shar ...
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
In a telecommunications network, a link is a communication channel that connects two or more devices for the purpose of data transmission. The link may be a dedicated physical link or a virtual circuit that uses one or more physical links or shar ...
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
The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...
, and can support any application which can operate on such a network and bit rate constraints.
Standard revisions
![Huawei E173 3G HSPA+ Modem USB Movistar Colombia (6)](https://upload.wikimedia.org/wikipedia/commons/0/08/Huawei_E173_3G_HSPA%2B_Modem_USB_Movistar_Colombia_%286%29.jpg)
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 (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network, or a cloud computing service, particularly the performance seen by the users of the network. To quantitat ...
(to improve latency) and higher rates on the forward and reverse link. In late 2006, Revision B (Rev. B) was published, whose features include 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 Rev. B involves a software update of the cell site modem, and additional equipment for new EV-DO carriers. Existing cdma2000 operators may have to retune some of their existing 1xRTT channels to other frequencies, as 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
Qualcomm () is an American multinational corporation headquartered in San Diego, California, and incorporated in Delaware. It creates semiconductors, software, and services related to wireless technology. It owns patents critical to the 5G, 4 ...
in 1999 to meet
IMT-2000 IMT-2000 (International Mobile Telecommunications-2000) is the global standard for third generation ( 3G) wireless communications as defined by the International Telecommunication Union.
In 1999 ITU approved five radio interfaces for IMT-2000 as a ...
requirements for a greater-than-2Mbit/s down link for stationary communications, as opposed to mobile communication (i.e., moving cellular phone service). Initially, the standard was called High Data Rate (HDR), but was renamed to 1xEV-DO after it was ratified by the
International Telecommunication Union
The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Unio ...
(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, due to possible negative connotations of the word "only", the "DO"-part of the standard's name 1xEV-DO was changed to stand for "Data Optimized", the full name - 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 market-friendly emphasis of the technology being data-optimized.
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 in favorable RF conditions with very complex
modulation
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...
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, which include the 'pilot', which helps the mobile find and identify the channel, the
Media Access Channel (MAC) which tells the mobile devices when their data is scheduled, and the 'control channel', which contains other information the network needs the mobile devices to know.
The
modulation
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...
to be used to communicate with a given mobile unit is determined by the mobile device 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 a 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:
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 acknowledged.
Reverse link structure
The reverse link (from the mobile back to the
Base Transceiver Station
A base transceiver station (BTS) is a piece of equipment that facilitates wireless communication between user equipment (UE) and a network. UEs are devices like mobile phones (handsets), WLL phones, computers with wireless Internet connectivity, ...
) 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
Hybrid automatic repeat request (hybrid ARQ or HARQ) is a combination of high-rate forward error correction (FEC) and automatic repeat request (ARQ) error-control. In standard ARQ, redundant bits are added to data to be transmitted using an er ...
). Only the reverse link has any sort of
power control
Power control, broadly speaking, is the intelligent selection of transmitter power output in a communication system to achieve good performance within the system.Guowang Miao, Jens Zander, Ki Won Sung, and Ben Slimane, Fundamentals of Mobile Data ...
, 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
Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency reference signal (the carrier wave). The modulation is accomplished by varying the sine and cosine inputs at ...
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
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet t ...
.
The additional forward rates for EV-DO Rev. An are:
In addition to the changes on the forward link, the reverse link was enhanced to support higher complexity
modulation
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...
(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 following enhancements:
* 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
Video on demand (VOD) is a media distribution system that allows users to access videos without a traditional video playback device and the constraints of a typical static broadcasting schedule. In the 20th century, broadcasting in the form of o ...
.
* Reduced latency by using
statistical multiplexing
Statistical multiplexing is a type of communication link sharing, very similar to dynamic bandwidth allocation (DBA). In statistical multiplexing, a communication channel is divided into an arbitrary number of variable bitrate digital channels or ...
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
CDMA2000 (also known as C2K or IMT Multi‑Carrier (IMT‑MC)) is a family of 3G mobile technology standards for sending voice, data, and signaling data between mobile phones and cell sites. It is developed by 3GPP2 as a backwards-compatible ...
mobile phone standard for next generation applications and requirements. It was proposed by
Qualcomm
Qualcomm () is an American multinational corporation headquartered in San Diego, California, and incorporated in Delaware. It creates semiconductors, software, and services related to wireless technology. It owns patents critical to the 5G, 4 ...
as the natural evolution path for 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
fourth-generation technology, which would make it compete with
LTE and
WiMAX
Worldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide physical layer (PHY) and media access control (MAC) options.
The WiMAX ...
. These technologies use a high bandwidth, low latency, underlying
TCP/IP
The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...
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
High-definition video (HD video) is video of higher resolution and quality than standard-definition. While there is no standardized meaning for ''high-definition'', generally any video image with considerably more than 480 vertical scan lines ( ...
streaming and mobile gaming.
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 systems.
UMB's use of OFDMA would have eliminated many of the disadvantages of the 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 intellectual property.
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 management technologies.
In November 2008,
Qualcomm
Qualcomm () is an American multinational corporation headquartered in San Diego, California, and incorporated in Delaware. It creates semiconductors, software, and services related to wireless technology. It owns patents critical to the 5G, 4 ...
, 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 either
WiMAX
Worldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide physical layer (PHY) and media access control (MAC) options.
The WiMAX ...
or the competing
3GPP Long Term Evolution
In telecommunications, long-term evolution (LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/EDGE and UMTS/HSPA standards. It improves on those standards' capacity and speed by usi ...
(LTE) standard as their 4G technology. In fact no carrier had announced plans to adopt UMB.
Qualcomm halts UMB project
Reuters, November 13th, 2008
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.
Features
* OFDMA
Orthogonal frequency-division multiple access (OFDMA) is a multi-user version of the popular orthogonal frequency-division multiplexing (OFDM) digital modulation scheme. Multiple access is achieved in OFDMA by assigning subsets of subcarriers to ...
-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 & pico-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
In radio, multiple-input and multiple-output, or MIMO (), is a method for multiplying the capacity of a radio link using multiple transmission and receiving antennas to exploit multipath propagation. MIMO has become an essential element of wi ...
, SDMA and Beamforming
Beamforming or spatial filtering is a signal processing technique used in sensor arrays for directional signal transmission or reception. This is achieved by combining elements in an antenna array in such a way that signals at particular angles e ...
* Higher Reverse Link (RL) sector capacity with quasi-orthogonal reverse link
* Increased cell edge user data rates using adaptive interference management
** 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 performance
* Power optimization through use of quick paging and semi-connected state
* Low-overhead signaling using flexible airlink resource management
* Fast access and request using RL CDMA
Code-division multiple access (CDMA) is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communicatio ...
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 beacons
* Multi-carrier configuration supports incremental deployment & mix of low-complexity & wideband devices
See also
* 3GPP2
* 4G
* CDMA2000
CDMA2000 (also known as C2K or IMT Multi‑Carrier (IMT‑MC)) is a family of 3G mobile technology standards for sending voice, data, and signaling data between mobile phones and cell sites. It is developed by 3GPP2 as a backwards-compatible ...
* Evolved EDGE
* Flash-OFDM
In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital transmission and a method of encoding digital data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communi ...
* High-Speed Downlink Packet Access
High Speed Packet Access (HSPA) is an amalgamation of two mobile protocols—High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA)—that extends and improves the performance of existing 3G mobile telecommunic ...
or HSDPA
High Speed Packet Access (HSPA) is an amalgamation of two mobile protocols—High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA)—that extends and improves the performance of existing 3G mobile telecommunic ...
* Mobile broadband
Mobile broadband is the marketing term for Wireless broadband, wireless Internet access via mobile networks. Access to the network can be made through a portable modem, wireless modem, or a Tablet computer, tablet/smartphone (possibly Tetherin ...
* Mobile broadband modem
A mobile broadband modem, also known as wireless modem or cellular modem, is a type of modem that allows a personal computer or a router to receive wireless Internet access via a mobile broadband connection instead of using telephone or cable t ...
* OFDM
In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital transmission and a method of encoding digital data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital commu ...
* List of device bandwidths
* List of Evolution-Data Optimized network equipment suppliers
* List of CDMA2000 networks
A list of CDMA2000 networks worldwide.
Active networks
Defunct networks
See also
* List of mobile network operators
For a more comprehensive list of mobile phone operators, see Mobile country codes.
Terrestrial
This is a l ...
* LTE
* Simultaneous Voice and EV-DO data (SVDO)
* WiMAX
Worldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide physical layer (PHY) and media access control (MAC) options.
The WiMAX ...
Notes and references
External links
3GPP2
CDMA2000 standards and specification documents
CDMA Development Group (CDG)
EVDOforums.com
EV-DO discussion group
A video demonstration of EVDO Rev. B capabilities
{{Mobile telecommunications standards
Code division multiple access
3rd Generation Partnership Project 2 standards