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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 BREW - is Qualcomm's open source application development platform for wireless devices equipped for CDMA technology. 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. 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. 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. 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. 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

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