Evolution-Data Optimized - AbsoluteAstronomy.com

Evolution-Data Optimized or Evolution-Data only (EV-DO, EV, etc.) is a telecommunication

Telecommunication

Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...

s standard for the wireless

Wireless

Wireless telecommunications is the transfer of information between two or more points that are not physically connected. Distances can be short, such as a few meters for television remote control, or as far as thousands or even millions of kilometers for deep-space radio communications...

transmission of data through radio

Radio

Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...

signals, typically for broadband Internet access

Broadband Internet access

Broadband Internet access, often shortened to just "broadband", is a high data rate, low-latency connection to the Internet— typically contrasted with dial-up access using a 56 kbit/s modem or satellite Internet with inherently high latency....

. It uses multiplexing

Multiplexing

The multiplexed signal is transmitted over a communication channel, which may be a physical transmission medium. The multiplexing divides the capacity of the low-level communication channel into several higher-level logical channels, one for each message signal or data stream to be transferred...

techniques including code division multiple access

Code division multiple access

Code division multiple access is a channel access method used by various radio communication technologies. It should not be confused with the mobile phone standards called cdmaOne, CDMA2000 and WCDMA , which are often referred to as simply CDMA, and use CDMA as an underlying channel access...

(CDMA) as well as time division multiplexing (TDM) to maximize both individual users' throughput and the overall system throughput. It is standardized by 3rd Generation Partnership Project 2

3rd Generation Partnership Project 2

The 3rd Generation Partnership Project 2 is a collaboration between telecommunications associations to make a globally applicable third generation mobile phone system specification within the scope of the ITU's IMT-2000 project...

(3GPP2) as part of the CDMA2000

CDMA2000

CDMA2000 is a family of 3G mobile technology standards, which use CDMA channel access, to send voice, data, and signaling data between mobile phones and cell sites. The set of standards includes: CDMA2000 1X, CDMA2000 EV-DO Rev. 0, CDMA2000 EV-DO Rev. A, and CDMA2000 EV-DO Rev. B...

family of standards and has been adopted by many mobile phone

Mobile phone

A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...

service providers around the world – particularly those previously employing CDMA networks. It is also used on the Globalstar

Globalstar

Globalstar is a low Earth orbit satellite constellation for satellite phone and low-speed data communications, somewhat similar to the Iridium satellite constellation and Orbcomm satellite systems.-History:...

satellite phone

Satellite phone

A satellite telephone, satellite phone, or satphone is a type of mobile phone that connects to orbiting satellites instead of terrestrial cell sites...

network.

EV-DO was designed as an evolution of the CDMA2000

CDMA2000

(IS-2000) standard that would support high data rates and could be deployed alongside a wireless carrier's voice services. An EV-DO channel has a bandwidth of 1.25 MHz, the same bandwidth size that IS-95A (IS-95

IS-95

Interim Standard 95 is the first CDMA-based digital cellular standard by Qualcomm. The brand name for IS-95 is cdmaOne. IS-95 is also known as TIA-EIA-95....

) and IS-2000 (1xRTT

CDMA2000

) use. The channel structure, on the other hand, is very different. Additionally, the back-end network is entirely packet-based

Packet switching

Packet switching is a digital networking communications method that groups all transmitted data – regardless of content, type, or structure – into suitably sized blocks, called packets. Packet switching features delivery of variable-bit-rate data streams over a shared network...

, 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.

Standard revisions

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

The quality of service refers to several related aspects of telephony and computer networks that allow the transport of traffic with special requirements...

(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.

TIA-856 Release 0

The initial design of EV-DO was developed by Qualcomm

Qualcomm

Qualcomm is an American global telecommunication corporation that designs, manufactures and markets digital wireless telecommunications products and services based on its code division multiple access technology and other technologies. Headquartered in San Diego, CA, USA...

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 International Telecommunication Union

International Telecommunication Union

The International Telecommunication Union is the specialized agency of the United Nations which is responsible for information and communication technologies...

(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

CDMA2000

(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.

Because you do not voice communications, employing high-efficiency coding delay becomes large. In the packet communication CDMA2000 1x is being used by a soft handover to receive data from multiple sectors, this approach because it needs to transmit data according to the sectors poor quality most of the sectors targeted, EV- do not use soft handover on the downlink in the DO. RAKE receiver for receiving multi-path from the same sector have been made, however.

TIA-856 Rel. 0 forward link channel structure

The primary characteristic that differentiates an EV-DO channel from a 1xRTT channel is that it is time multiplexed

Time-division multiplexing

Time-division multiplexing is a type of digital multiplexing in which two or more bit streams or signals are transferred apparently simultaneously as sub-channels in one communication channel, but are physically taking turns on the channel. The time domain is divided into several recurrent...

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

Modulation

In electronics and telecommunications, modulation is the process of varying one or more properties of a high-frequency periodic waveform, called the carrier signal, with a modulating signal which typically contains information to be transmitted...

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)

MAC address

A Media Access Control address is a unique identifier assigned to network interfaces for communications on the physical network segment. MAC addresses are used for numerous network technologies and most IEEE 802 network technologies, including Ethernet...

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

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:

DRC Index	Data rate (kbit/s) Bit rate In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....	Slots scheduled	Payload size (bits)	Code Rate Code rate In telecommunication and information theory, the code rate of a forward error correction code is the proportion of the data-stream that is useful...	Modulation Modulation In electronics and telecommunications, modulation is the process of varying one or more properties of a high-frequency periodic waveform, called the carrier signal, with a modulating signal which typically contains information to be transmitted...	SNR Signal-to-noise ratio Signal-to-noise ratio is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. It is defined as the ratio of signal power to the noise power. A ratio higher than 1:1 indicates more signal than noise... Reqd.
1	38.4	16	1024	1/5	QPSK	-12
2	76.8	8	1024	1/5	QPSK	-9.6
3	153.6	4	1024	1/5	QPSK	-6.8
4	307.2	2	1024	1/5	QPSK	-3.9
5	307.2	4	2048	1/5	QPSK	-3.8
6	614.4	1	1024	1/3	QPSK	-0.6
7	614.4	2	2048	1/3	QPSK	-0.8
8	921.6	2	3072	1/3	8-PSK	1.8
9	1228.8	1	2048	2/3	QPSK	3.7
10	1228.8	2	4096	1/3	16-QAM	3.8
11	1843.2	1	3072	2/3	8-PSK	7.5
12	2457.6	1	4096	2/3	16-QAM	9.7

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

Turbo code

In information theory, turbo codes are a class of high-performance forward error correction codes developed in 1993, which were the first practical codes to closely approach the channel capacity, a theoretical maximum for the code rate at which reliable communication is still possible given a...

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.

TIA-856 Rel. 0 reverse link structure

The reverse link (from the mobile back to the Base Transceiver Station

Base Transceiver Station

A base transceiver station or cell site is a piece of equipment that facilitates wireless communication between user equipment and a network. UEs are devices like mobile phones , WLL phones, computers with wireless internet connectivity, WiFi and WiMAX gadgets etc...

) on EV-DO Rel. 0 operates very similar to that of 3G1X CDMA

CDMA2000

. 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

Power control

Power control, broadly speaking, is the intelligent selection of transmit power in a communication system to achieve good performance within the system. The notion of "good performance" can depend on context and may include optimizing metrics such as link data rate, network capacity, geographic...

, 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

CDMA2000

).

All of the reverse link channels are combined using code division

Code division multiple access

and transmitted back to the base station using QPSK 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.

Because you do not voice communications, employing high-efficiency coding delay becomes large. In the packet communication CDMA2000 1x is being used by a soft handover to receive data from multiple sectors, this approach because it needs to transmit data according to the sectors poor quality most of the sectors targeted, EV- do not use soft handover on the downlink in the DO. RAKE receiver for receiving multi-path from the same sector have been made, however.

TIA-856 Rev. 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

Quality of service

The quality of service refers to several related aspects of telephony and computer networks that allow the transport of traffic with special requirements...

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. A are:

DRC Index	Data rate in kbit/s Bit rate In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....	Slots scheduled	Payload size (bits)	Code Rate Code rate In telecommunication and information theory, the code rate of a forward error correction code is the proportion of the data-stream that is useful...	Modulation Modulation In electronics and telecommunications, modulation is the process of varying one or more properties of a high-frequency periodic waveform, called the carrier signal, with a modulating signal which typically contains information to be transmitted...
13	1536	2	5120	5/12	16-QAM
14	3072	1	5120	5/6	16-QAM

In addition to the changes on the forward link, the reverse link was enhanced to support higher complexity modulation

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 500-1000kbit/s but with more latency than cable and dsl.

TIA-856 Rev. 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
Carrier wave
In telecommunications, a carrier wave or carrier is a waveform that is modulated with an input signal for the purpose of conveying information. This carrier wave is usually a much higher frequency than the input signal...

(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 enables new services such as high definition
High-definition video
High-definition video or HD video refers to any video system of higher resolution than standard-definition video, and most commonly involves display resolutions of 1,280×720 pixels or 1,920×1,080 pixels...

video streaming.
Reduced latency by using statistical multiplexing
Statistical multiplexing
Statistical multiplexing is a type of communication link sharing, very similar to dynamic bandwidth allocation . In statistical multiplexing, a communication channel is divided into an arbitrary number of variable bit-rate digital channels or data streams. The link sharing is adapted to the...

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.

Rev. MC

CDMA2000 1x-EV-DO Rev. MC (Multicarrier Rev. Caleb aka Agent - MC (Multi Carrier Rev agent) / Rev.A + (Rebuepurasu)]) is the aforementioned Rev.B Some specs of the (multi-carrier transmission) was adopted as a subset, for example, KDDI and Okinawa Cellular Telephone, EV of up to 1.8Mbps uplink 3.1Mbps / up to three down-wave transmission bundles DO Rev.A, assumed rate of about 5Mbps uplink communication 9Mbps / down, it hopes to improve 5 to 10% more traffic.
　Modulation scheme such as that mentioned above is a basic and common Rev.A, but facilities such as base stations associated with software updates, MC-terminal unless the terminal for voice and data communications supporting Rev.A This communication system can not be used with caution [3] [4] .
　Note that initially, was becoming increasingly assuming a 5Mbps upstream standard 9Mbps / downlink, information and communication technology workshop in September 2009, due to adopt the 64QAM modulation scheme, uplink 14.7Mbps / maximum download reported to be up to 5.5Mbps and [5] what has been, settled on the communication speed of up 5.5Mbps 9.2Mbps / downlink 64QAM non-adoption of the final.

EV-DV

CDMA2000 1x EV-DV (1x Evolution Data and Voice) is an improved specification 1xMC, to not have enough frequency region, high-speed packet communication is performed in the same bandwidth for both voice and data. However, the U.S. Qualcomm is terminated as such unlikely to develop sufficient demand.

TIA-1121

Ultra Mobile Broadband (UMB) was proposed by Qualcomm

Qualcomm

as the natural evolution path for CDMA2000.

In November 2008, Qualcomm

Qualcomm

, UMB

Ultra Mobile Broadband

UMB was the brand name for a project within 3GPP2 to improve the CDMA2000 mobile phone standard for next generation applications and requirements...

's lead sponsor, announced it was ending development of the technology. This followed the announcement that most CDMA carriers chose to adopt the competing 3GPP Long Term Evolution

3GPP Long Term Evolution

3GPP Long Term Evolution, usually referred to as LTE, is a standard for wireless communication of high-speed data for mobile phones and data terminals. It is based on the GSM/EDGE and UMTS/HSPA network technologies, increasing the capacity and speed using new modulation techniques...

(LTE) standard.

Potential competing standards

Motorola

Motorola, Inc. was an American multinational telecommunications company based in Schaumburg, Illinois, which was eventually divided into two independent public companies, Motorola Mobility and Motorola Solutions on January 4, 2011, after losing $4.3 billion from 2007 to 2009...

proposed a new system called 1Xtreme as an evolution of CDMA2000

CDMA2000

, but it was rejected by the 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. In comparison, EV-DO requires 1 or more (1.25 MHz) freq. bands in addition to the voice band. (EV-DO Rev. A could potentially support a VoIP overlay network

Overlay network

An overlay network is a computer network which is built on the top of another network. Nodes in the overlay can be thought of as being connected by virtual or logical links, each of which corresponds to a path, perhaps through many physical links, in the underlying network...

for voice calling, but this has not been pursued except for PTT, see QChat

QChat

QChat is a Push-to-Talk technology developed by Qualcomm.The QChat software application was developed by Qualcomm Internet Services a division of Qualcomm and part of the Qualcomm Wireless and Internet group...

).

At the time, there was much debate on the relative merits of DV and DO. Traditional operators with an existing voice network preferred DV, since it does not require a separate band. 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 circuit

Application-specific integrated circuit

An application-specific integrated circuit is an integrated circuit customized for a particular use, rather than intended for general-purpose use. For example, a chip designed solely to run a cell phone is an ASIC...

s (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

Verizon Wireless

Cellco Partnership, doing business as Verizon Wireless, is one of the largest mobile network operators in the United States. The network has 107.7 million subscribers as of 2011, making it the largest wireless service provider in America....

, then Sprint Nextel

Sprint Nextel

Sprint Nextel Corporation is an American telecommunications company based in Overland Park, Kansas. The company owns and operates Sprint, the third largest wireless telecommunications network in the United States, with 53.4 million customers, behind Verizon Wireless and AT&T Mobility...

in 2004 and smaller operators in 2005 announced their plans to deploy EV-DO. In March 2005, Qualcomm suspended development of EV-DV chipsets, and focused on improving the EV-DO product line.

External links

3GPP2.org CDMA2000 standards documents
CDMA Development Group (CDG)
EVDOforums.com EV-DO discussion group
A video demonstration of EVDO Rev. B capabilities

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Standard revisions

TIA-856 Release 0

TIA-856 Rel. 0 forward link channel structure

TIA-856 Rel. 0 reverse link structure

TIA-856 Rev. A

TIA-856 Rev. B

Rev. MC

EV-DV

TIA-1121

Potential competing standards

See also

External links