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What Is EVDO?

Mobile devices using EVDO can quickly download data.
A cell phone that works with EVDO.
EVDO devices are always "on" when there is a connection to a tower.
Article Details
  • Originally Written By: Damir Wallener
  • Revised By: Mary McMahon
  • Edited By: L. S. Wynn
  • Last Modified Date: 18 June 2014
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EVDO is a protocol for high speed wireless broadband. Also known as EV-DO, 1xEvDO and 1xEV-DO, it's one of several major Third Generation (3G) wireless data standards. Mobile devices that use EVDO technology can upload and download data quickly, and the technology is always "on" whenever there is a signal from the wireless tower. Unlike a WiFi® connection, a device with EVDO does not need to be near a wireless hotspot; instead, the cell phone can itself become a hotspot and share its Internet connection with other devices.

Officially, the name defined by the Telecommunication Industry Association for this technology is "CDMA2000, High Rate Packet Data Air Interface." The acronym EVDO is short for "Evolution, Data Only" or "Evolution, Data Optimized," a reflection of the fact that it is the next evolution of the earlier Code Division Multiple Access 2000 (CMDA2000) family of wireless products. The EVDO standard was developed in 1999, but the protocol has been upgraded since then to improve its speed.

3G and CDMA

3G is designed to transmit voice and high-speed mobile data to people on the go. Several competing technologies are involved in the development of 3G networks as technology companies work on the best way to handle the mounting demand for wireless services around the world. Many firms invested in the development of 3G networks and technology use the Code Division Multiple Access (CDMA) approach, which has proved highly effective with mobile phone networks.

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The biggest obstacle to implementing high speed wireless networks is the lack of bandwidth, or range of usable frequencies. Just as only so many radio stations can be squeezed onto the FM dial, only so much data can be transmitted across the available bandwidth. As the user load increases, the available frequencies tighten, and users can experience delays, dropped data, and other problems. Thus, providers have been working to find ways to use bandwidth more efficiently without sacrificing clarity and quality for their users.

How CDMA Works

CDMA uses advanced mathematical techniques to allow multiple wireless devices to transmit simultaneously on the same radio frequency. Every device, such as a cell phone, is assigned a unique mathematical signature. Transmitters apply this signature to the original signal and send a modified version. A receiver applies the inverse of the mathematical operation to recover the original signal.

The term "CDMA" is used both to refer generally to a channel access method and to the specific technologies that use that method as a backbone for radio transmissions. The intended meaning is usually clear from the context. CDMA2000, for example, is a data handling standard that uses CDMA technology.

How EVDO Works

Traditional wireless networks create a direct path between receiving and sending devices, much like traditional telephone networks. EVDO instead breaks data into individual packets, the same technique for data handling used on the Internet. Each packet is sent independently of all the other packets. This saves bandwidth for use by other devices; when neither party on a phone call is speaking, for example, the connection consumes no bandwidth. When an Internet site is accessed, no bandwidth is used until the site starts sending the web page.

The original EVDO protocol, called Revision 0, has a theoretical throughput of 2.4 megabits per second (Mbps). This is as fast as many wired DSL and cable broadband connections currently available in the United States. The upgrade to Revision A increases speed to a theoretical 3.1 Mbps. A third upgrade, to Revision B, was released in January 2010, although it is not fully deployed; Qualcomm, the developer, predicts download speeds as fast as 14.7 Mbps in some situations.

Qualcomm has produced impressive demonstrations of EVDO's capabilities. In one, a video conference was conducted with a participant traveling in a car at 60 mph (96 kph). Transferring the large amounts of data required for video conferencing is a major challenge, especially at such speeds. In another demonstration, a phone call was placed from a bullet train moving in excess of 150 mph (240 kph).

UMTS and HSDPA

The biggest challenge to EVDO has been the Universal Mobile Telecommunications System (UMTS). UMTS — which is sometimes known by the name of its radio interface standard, Wideband-CDMA (WCDMA) — uses larger bands for data transmission. This approach can be less vulnerable to interception and jamming than some other wireless technologies. Data transfer speeds are slower than with EVDO, however, with speeds of up to 2 Mbps.

HSDPA, which stands for High-Speed Downlink Packet Access, was built on WCDMA technology, but with a number of significant changes in the way that data is handled. This protocol is considered 3.5G or enhanced 3G, a step above 3G but not quite fourth generation. HSDPA shares one transmission channel between multiple users, and schedules data transfer to take advantage of the best possible conditions; this means that data may be sent to multiple users at the same time. Different speed versions of HSDPA are typically available to consumers, with download speeds ranging from 1.8 Mbps to 21 Mbps or higher.

How Does This Affect Users?

An advantage of EVDO is that it uses the same broadcasting frequencies as existing CDMA networks. As purchasing spectrum from regulatory agencies is extremely expensive, this brings down the cost of building and using new networks. HSDPA, while offering faster download speeds with the higher levels of service, may also be more expensive for the consumer.

Mobile Internet users should remember that what standard is used for transmitting data is usually dependent on the network; a cell phone from Verizon in the US will have access to EVDO, for example, but not HSDPA. Users who will be traveling in foreign countries with wireless devices may want to check to see if they are supported on a given network. For frequent travelers, it may be advisable to consider investing in a device that will work reliably on international networks in order to avoid problems with dropped calls, inability to send data, and other issues.

As new wireless standards develop, the quality of wireless services tends to improve. Various options are not available in all areas, and may have differing rates of performance. Newer technologies can come with unexpected kinks and service plans may be more costly. Early adopters can also find it difficult to access technical support and assistance, as technicians may not be as familiar with the products they are using.

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Discuss this Article

anon320240
Post 26

Interesting, brief description. It helped me to understand how a mobile communications operator in Cameroon, Camtel, could offer 3G services without having access to WCDMA frequencies.

anon296017
Post 25

What is meant by 1g 2g and 4g?

anon206345
Post 23

I cannot understand the history of cdma and

all its family like fdma, tdma, cdma and so on.

anon132080
Post 22

i lost my Cdma2000 1x Evdo Bsnl Card setup cd. what i am doing now?

anon107693
Post 21

I have EVDO for my laptop and cable Internet for my home. There is no comparison. I live in Central California, and the d/l (download) and u/l (upload) speeds suck. I will occasionally hit an area where it increases slightly, but still below most DSL systems. And never even close to cable broadband. Also it has the annoying habit of losing the EVDO signal at random, and on my Netbook it requires a complete restart to reconnect. The only advantage is portability in the field.

anon92904
Post 20

i use evdo through virgin mobile (which rides on sprint), and the service is spotty at best. i live in los angeles. some areas of town are better than others. on average i get about 300k to 800k down and between 180k and 280k up, but the speed varies greatly.

my biggest complaint is that the radio drops the signal a lot -- a whole lot -- 20 times a day or so, and i often get the message that there's a problem with the device. the fix for that is to go into the device interface, hit "program device" and that usually takes care of it.

it's a convenient tool when you need to hop on the net anywhere, but not nearly as reliable as i would have hoped. nothing beats a hard wired connection on adsl or cable.

it's better than nothing, but not nearly as reliable as the hype. cheers! Bryan

anon84718
Post 19

EVDO is best because we can use it anywhere around india, with broadband speed on a wireless device.

i'm using this network through a samsung corby handset and i've got the 2.4 mbps speed on my laptop or mobile device.

Thanks to Reliance Communication to import this network into India.

anon72165
Post 17

I am a freelance tv journalist and often have to send video files via ftp.what i have discovered is that all these names 2g, 3g, hsdpa, evdo, etc. are all buzzwords. all talk and no action. when it comes to actually sending video files, a satellite uplink is probably your best bet.

anon66184
Post 16

My BSNL EVDO USB data card was working fine since about 1 and a half years. However, a few days back, it has stopped working. Computer is not able to scene it properly and is giving the message that "Your device has malfunctioned".

If I attempt to run EVDO software, it is not recognising the device and "no device or device not ready to work" message is coming just after detecting hardware message.

I showed it to the local BSNL office but they were not able to rectify it. I also showed it to a mobile repairer and he tried to clean inside and test but that also did not help. Can you please tell me where can I get it repaired? I live in Bilaspur, CG, India.

anon64383
Post 15

EVDO connection in Hyderabad India from Virgin mobile, Download speed is up to 3.1 Mbps, upload speed is up to 1.8 Mbps.

anon56114
Post 14

Great technology man. It can work from anywhere, also here in India we are getting great speeds. A laptop and the small dongle are sufficient to carry -- V. Patane.

anon52453
Post 13

i'm from ethiopia and this device is so helpful. it connects at 960kbps. Thanks to the technology we will expect even more. It's real broadband. Cheers!

anon51212
Post 12

Salman here! Well EVDO had been introduced in Pakistan around three to four years back, by more than one ISP i think, and it's amazing.

anon45849
Post 11

I am from India. EvDO service is available from bsnl. I got 40-110 kbps downloading speed. It's great to be able to connect to the internet from anywhere. --Arindam Choudhury

jofiji
Post 10

EVDO is also available here in the Fiji Islands. Local ISP, Connect Fiji has Mobile Internet which runs on EVDO and CDMA. Outside the 3G areas the connection falls back to Telecom Fiji's bigger CDMA network. You can access the internet from virtually anywhere.

anon42532
Post 9

Estonia located in Europe has full coverage of EVDO. Highest speed i have reached is 1.7 Mbps download.

anon41924
Post 8

Soon EVDO service will be implemented in Ghana. The gateway to Africa.

anon41179
Post 7

In Norway we got 2,4 Mbps transfer rate. aprox. 2-300Kbps upload. Theoretically 3.2Mbps down and 1.8Mbps up. This is over EVDO.

anon37566
Post 6

hope to also enjoy evdo services in Ghana as a current cdma technology operator is being improving to the evdo technology. --Elikem.

anon32490
Post 5

i am currently on a CDMA EVDO 8330 and i am contemplating moving to Europe...well hopefully they get a CDMA network in England soon.

anon22753
Post 4

I live in Nigeria. My experience with EVDO is better to CDMA, but the transfer rate, as opposed to that theoretically stated, isn't quite impressive.

anon20403
Post 3

I love being able to connect from almost anywhere, so i decided to have an evdo connection, by the way my ISP did not made any visit to the area where I live prior to offering the service, so I am now using an excellent technology but unfortunately with a very low transfer rate.

The best transfer rate I have experienced is about 60 kb/s download ...

concordski
Post 2

some new laptops have evdo built in. my tablet pc has a built in antenna that i can extend to get better coverage. i just click on one button, and i get an evdo connection (if i am in an evdo area). its amazingly convenient, but it costs about $60 per month.

i suspect that in a few years, these external dongles or pcmcia cards will be replaced by built-in systems - this is exactly what happened with wi-fi.

malena
Post 1

I replaced my cable internet access with EVDO (by Sprint). I love being able to connect from almost anywhere. What sucks though is having to have a dongle to connect to the internet, and worse, having a slow transfer rate. I think the transfer rate I experience is much less than the "theoretical throughput" stated in this article and in the sales literature of service providers. I live in Los Angeles and get about 830 kb/s download and 350 kb/s upload.

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