Basics about CDMA / EVDO

[Karthik R 246]

New members, (why even me in the beginning!) go nuts over technical jargon that they may not fully follow. I am posting this topic with a view to help them comprehend better and understand CDMA which I feel is not given due appreciation. Post the additional essential details here but lets spare the argument on GSM v/s CDMA Experienced members kindly view this as a venue to refresh and share updated info.

CDMA operators in India

CDMA (code division multiple access) is a digital mobile telephone standard which takes a different approach to the other, competing standards: GSM (Global System for Mobile Communications) and TDMA (Time Division Multiple Access). Where GSM and TDMA divide the available bandwidth into 'channels' using a combination of frequency bands and time-slices, CDMA spreads the signal over a wide bandwidth, identifying each channel using unique digital codes. This means it can provide greater bandwidth efficiency, and hence a greater potential number of channels.

Traditional uses of spread spectrum are in military operations. Because of the wide bandwidth of a spread spectrum signal, it is very difficult to jam, difficult to interfere with, and difficult to identify. This is in contrast to technologies using a narrower bandwidth of frequencies. Since a wideband spread spectrum signal is very hard to detect, it appears as nothing more than a slight rise in the "noise floor" or interference level. With other technologies, the power of the signal is concentrated in a narrower band, which makes it easier to detect. The narrow band is also more prone to interference than the spread-spectrum of CDMA.

Increased privacy is inherent in CDMA technology. CDMA phone calls will be secure from the casual eavesdropper since, unlike an analog conversation, a simple radio receiver will not be able to pick individual digital conversations out of the overall RF radiation in a frequency band. TDMA (time division multiple access) and GSM systems have to add an extra stage of encryption to the signal to ensure privacy, whereas encryption is inherent to the CDMA system.

The 1× Evolution-Data Optimised, which is abbreviated as EV-DO or 1× EV-DO, is a wireless radio broadband data standard. It has been adopted by a number of CDMA mobile telecommunications service providers across the world, particularly in the USA, South Korea, Japan, eastern European countries, Australia, Canada, New Zealand and spreading in our very own India

The technology was first standardised by 3GPP2 in 2000 as part of the CDMA2000 standards. Qualcomm started to develop EV-DO in 1999 in a bid to produce a 2Mbit/s downlink for stationary communications, according to the requirements of IMT-2000.

Originally the DO of the standards acronym stood for 'data only'. However, after being ratified by the International Telecommunications Union (ITU), the 'O' was changed to 'optimised' since 'only' had negative connotations for marketing the technology. EV-DO technology is a direct evolution of the 1× (1×RTT) air interface standard, with its channels carrying data traffic only.

HOW DOES IT MATCH UP?

In comparison to GPRS and EDGE standards, which have been widely adopted by GSM networks, the 1× EV-DO capability of enabled CDMA2000 networks is much faster. It provides mobile devices (handsets and wireless modem air cards) with air interface speeds of up to 2.4576Mb/s with EV-DO Rev. 0 and even faster speeds of 3.1Mb/s with Rev. A (data only rev A, affectionately known as DORA).

Only devices fitted with 1xEV-DO capable chipsets can take advantage of the higher speeds. High speed downlink packet access (HSDPA) is a rival technology for wide band code division multiple access (W-CDMA) networks. HSDPA has the advantage over EV-DO of being able to maintain voice and data channels simultaneously over a single pair of frequencies.

The system has some real advantages over WiFi, including the fact that it is always on with seamless roaming. Additionally, the signal can travel on the same cell sites as mobile phones, can download and run video clips in real time, there is no 300ft range from the cell tower or 'hot spot' and there are not so many security issues.

DEPLOYMENT AND TECHNOLOGY

When deployed alongside a voice network, 1× EV-DO requires a separate radio channel of 1.25MHz. The first revision of the standard was 1x EV-DO Rev. 0 and this is now being superseded by 1× EV-DO Rev. A

In addition to the increase in the maximum downlink rate from 2.4576Mb/s in Rev. 0 to 3.1Mb/s, EVDO Rev.A also has a 12-times improvement in the maximum uplink data rate, from .15Mb/s to 1.8Mb/s.

EV-DO REVISION B

Even Rev. A is now due to be superseded, with the wireless communications market constantly striving for better and faster services. 1× EV-DO Rev B (DORB) specifications have now been developed.

EVDO Rev. B is the evolution of Rev. A and in addition to all that is provided in Rev A, provides additional enhancements such as: higher rates per carrier (up to 4.9Mbps on the downlink); higher rates by bundling multiple channels together (this can enhance user experience and enables new services such as high definition video streaming); reducing latency for services such as gaming and video telephony, due to statistical mutiplexing across channels and hybrid frequency re-use which reduces the interference from the adjacent sectors and improves the rates that can be offered especially to the users at the edge of the cell.

Where EVDO isn't available, 2G/1xRTT data capability will be present and your EVDO modem or phone will automatically connect to it. While considerably slower than EVDO, 1x is a huge boon - if you find yourself in a remote location with no EVDO connectivity, you will still be able to remain connected!

Commonly Used Abbreviations

• MIN - Mobile Identification Number
  
• ESN - Electronic Serial Number
  
• PRL - Preferred Roaming List
  
• SID - System Identification Number
  
• SCM - Station Class Mark
  
• CAI - Common Air Interface
  
• A Key - Authentication Key
  
• NAM - Numeric Assignment Module
  
• SPC - Service Programming Code
  

Glossary

1. BREW - is Qualcomm's open source application development platform for wireless devices equipped for CDMA technology.
   
2. RUIM or R-UIM - is a transferable identification card for mobile phones that belong to the CDMA network. RUIM cards store personal information, including the name and account number, the cell phone number, as well as the contacts' names and numbers. The RUIM cards also store text messages and any other important phone settings.
   
3. MEID - An ID number that is unique for each new CDMA mobile in the world. It identifies the phone to the network. MEID is a replacement for ESN. It began replacing ESN in 2005 since the pool of ESN numbers has been virtually exhausted due to the number of devices in use. It is equivalent to IMEI in GSM phones.
   
4. ESN - An ESN is a numeric identifier that uniquely identifies a CDMA phone. The ESN is what a CDMA network uses to identify a phone and determine which subscriber's account, if any, it is linked to. Because of this, when switching from one phone to another, subscribers will have to provide the ESN of the new phone to the network carrier before it can be activated. The ESN is being phased out in favour of the MEID. This is happening because phone manufacturers are literally running out of ESN identifiers.
   
5. OTA (Over-The-Air) - Any kind of event or transfer that takes place wirelessly using the cellular network as opposed to using a cable or other local connection.
   
6. PRL - is a database residing in a wireless (primarily CDMA) device, such as a cellphone, that contains information used during the system selection and acquisition process. In the case of RUIM-based CDMA devices, the PRL resides on the RUIM. The PRL indicates which bands, sub bands and service provider identifiers will be scanned and in what priority order. Without a PRL, the device may not be able to roam, i.e. obtain service outside of the home area.
   

Frequently Asked Questions :

1.How can I locate the ESN or MEID number on my phone?

All mobile devices are identified by an Electronic Serial Number (ESN) or a Mobile Equipment Indentifier (MEID). Some devices may display the ESN or MEID under the battery, below the battery or on the back of the phone.

Behind the Battery:

Below the Battery:

Back of the Phone:

Below are examples of labels that can be found on devices supporting ESN numbers. As ESN Is an 11-digit Electronic Serial Number. An ESN in hexadecimal, or HEX, is represented by 8 characters that are numbers and letters.

Below are examples of labels that can be found on devices that support MEID numbers. MEID is always hexadecimal, represented by 14 characters that are numbers and letters. The first digit is always A - F.

NOTE: Don't confuse the letter O with the number 0 (zero). It is always a zero. Only letters A-F are in an ESN/MEID.

Sourced info from the net and all recognition to them.

Found this good report on the technical side of CDMA which you may find interesting. Some of the details provided may be obsolete as it was written a while ago, please verify the same.

cdma.pdf

Edit - Frequently Asked Questions

Edited August 31, 2011 by Karthik R

[ramtech 47]

good info

[thilak.kmb 19]

Thank you Karthik. Both your msg and the attachment are like reading text book giving the basics. A very useful effort by you.

[HetalDP 947]

EVDO Rev A is Not Voice capable but surely it can support Voice over IP BUT the VoIP Support have never been rolled out later on 1x was Retained for Voice and EVDO only for Data so all current Handset Connect both 1x and EVDO Circuit Simultaneously

[parin 857]

Very nice info for Noobs

Thanks Kartik

[csmart 472]

good info..

@hetal so i think on EvDO we can have data & voice call simultaneously.

[dkaile 1,051]

^

On Reliance EVDO, still there will be no data and voice simultaneously; But you will not miss any calls as data transfer will stop for the duration of the voice call...

[cavarun 13]

+1

[HetalDP 947]

No EVDO Roll out in any part of world can carry Voice on it

EVDO = EVolution Data Only ||| and (EVDO+Voice) = EVDV (Evolution Data and Voice)

EVDV were never came from Table to Implementation

all world using EVDO only for Data and 1x for Voice

Just see the screen of Samsung Corby it show dual Cell Signals

[rajanmehta 4,056]

@Hetaldp

Does this mean that even if there is a Spectrum Auction sometime in future for CDMA EVDO (Which is being talked about quite often now).....

The additional spectrum can be utilized only for carrying EVDO Data and not voice...

What i mean to say is that will the voice quality in CDMA remain the same as today unlike in 3G GSM where technically one expect a better voice quality if you are on a 3G Voice+Data Plan?

And what about LTE network rollout by Verizon in U.S.? Is that also limited to High Speed Data with no Voice Carriage?

[rohan_4ever20 8]

+1,Bros for this

[csmart 472]

CDMA EvDO kaa auction hoga kya?? major player, tata and reliance both have got 3G.. further reliance is in huge debt, so bidding again will cost them dear..

LTE = Long term evaluation read the details on wikipedia...

its more techie stuff...

[Karthik R 246]

No EVDO Roll out in any part of world can carry Voice on it

EVDO = EVolution Data Only ||| and (EVDO+Voice) = EVDV (Evolution Data and Voice)

EVDV were never came from Table to Implementation

all world using EVDO only for Data and 1x for Voice

Just see the screen of Samsung Corby it show dual Cell Signals

On Reliance EVDO, still there will be no data and voice simultaneously; But you will not miss any calls as data transfer will stop for the duration of the voice call...

Thanks a ton for the valuable inputs

Updated post!

[Karthik R 246]

Need clarification :

MIN (Mobile Identification Number) can vary in the same mobile as it is assigned by the operator. True?

[HetalDP 947]

@Hetaldp

Does this mean that even if there is a Spectrum Auction sometime in future for CDMA EVDO (Which is being talked about quite often now).....

The additional spectrum can be utilized only for carrying EVDO Data and not voice...

What i mean to say is that will the voice quality in CDMA remain the same as today unlike in 3G GSM where technically one expect a better voice quality if you are on a 3G Voice+Data Plan?

And what about LTE network rollout by Verizon in U.S.? Is that also limited to High Speed Data with no Voice Carriage?

All Additional Auction for EVDO will only be used in Data Only

EVDV (EVolution Data and Voice) specification is Dropped

1x Advanced + EVDO Rev B = Data and Voice Simaltaneously

Reliance and TATA may also refarm there 1x spare carrier for Additional EVDO and Stop giving 1x Data at all in Congested area = 1x DATA is big big congestion maker and so is the Heavy Data Charges from TATA and Reliance

And there is only Single Carrier, there is lot of Over lap in between the Tower so is bad Data Rate, Multiple Carrier will smooth this Out.

as EVDO is Dedicated Carrier Congested Voice Network can never touch it

as with 1x Congested EVDO can never touch Voice Quality

1x Voice usage 4GV Codes = EVRC v2 is equallent to 3GSM Latest Codes for same quality we alreedy getting boys

[rajanmehta 4,056]

Hetalbhai For Excellent And Informative Answers For All Questions. +1

[gpkumaran 21]

A very useful Post...

[thackervijay 16]

karthik R, thankyou for this detailed information, very useful

Hetal DP, thankyou for your clarifications and information.Would like to know why did they dropped the idea of EVDV and never came out, i mean what are the cons and pros for the same that companies never realised to plan that out in market?

[Karthik R 246]

Would like to know why did they dropped the idea of EVDV

Let me answer that, as you know EV-DO suffers from its namesake implied - the limitation of carrying only data on a single channel. EV-DV [Evolution-Data and Voice] on the other hand merged data and voice on a single channel but become a commercial flop. Why?

Tracking EV-DV's decline is a fairly simple process - its fall is almost inversely proportional to EV-DO's success, starting with SK Telecom's deployment of EV-DO in 2002 to Verizon Wireless' and Japanese carrier KDDI's adoption of the technology. The critical holdout, however, was Sprint, EV-DV's last champion, and its signaling of an EV-DO rollout last year seemed to be the death knell for EV-DV.

The CDMA market simply could not support two competing technologies providing essentially the same capabilities. Vendors would be hard pressed to support two separate development tracks without high carrier demand for both but spreading the industry across two distinct infrastructures would undermine the economies of scale from having a unified platform.

Follow this link for more detailed analysis on the downfall of EV-DV

In March 2005, Qualcomm scrapped development of EV-DV chipsets and focused on improving the EV-DO product line

[thackervijay 16]

Karthik R, for your link and answer to my questions.

[Rahul Always 87]

Thanks for the post. Well it is indeed educative and I loved the simplicity of the post. Please continue to post such informative articles. Good for newbies (is it noobs) like me!

[lubu 1]

This help a lot...I just got a CDMA connection and have been struggling with the myriad terms and jargon's on posts here.

[_Kailash_ 63]

+1 Karthik nice info

[krishnendu halder 24]

but with the newer 4g device such as evo lte you will get evdo and voice simultaneously.Older devices did not support this.

[trEndchaser 2]

Nice article and very informative. Good topic to get all info in one place. Thanks