1. isaacleese's Avatar
    I see this question asked a lot here on CB, so I figured I'd make a post explaining the differences.

    GSM stands for Global System for Mobile communication. It's the accepted standard for cell phone radios in most of the world. A GSM handset uses the 850/900/1800/1900MHz frequencies to communicate with the cell towers. A GSM phone uses a Subscriber Identity Module (SIM) card and an International Mobile Equipment Identity (IMEI) number to identify itself to the cell network. GSM phones can either be locked to one carrier or be unlocked for use on any GSM carrier - in the first case, the phone can usually be unlocked either by the carrier that locked it or by a third party who may or may not charge a fee.

    GSM carriers use three data protocols: General Packet Radio Service (GPRS,) with a top speed of 114kbit/s; Enhanced Data rates for GSM Evolution (EGPRS, or EDGE) with a top speed of 238-473kbit/s; and HSPA, which in its various forms can have a top speed of up to 42mbit/s in its fastest version, HSPA+.

    The next step for GSM carriers is called GSM Long Term Evolution, which will provide an all-IP based network similar to the Internet and will provide greatly enhanced data access speeds.

    GSM carriers include at&t, T-Mobile, Rogers, Fido, Telcel, Movistar, 3, Orange, Vodafone, and most carriers worldwide.

    CDMA stands for Code Division - Multiple Access is an entirely different radio technology used mainly in western Asia and North America. CDMA carriers usually use similar frequencies to GSM carriers, but the two technologies are entirely incompatible. Most CDMA carriers forego the use of a Removable User Identity Module (RUIM) card, choosing instead to identify their handsets to the network solely using the handsets Electronic Serial Number (ESN,) which is analogous to the GSM IMEI number. Because of this, CDMA phones are not unlockable to be used on a carrier different than the one it is branded for (except in rare cases where a carrier will activate a device branded to another carrier.)

    CDMA carriers also use three data protocols: 1xRTT, with a top data speed of 144kbit/s; 1xEv-DO rev. A, with a top speed of 3.1mbit/s; and 3xEv-DO rev. B, with a top speed of 14.7mbit/s (note that as of this writing, Ev-DO rev. B has yet to be widely deployed by any carrier.)

    CDMA carrier's next step is also LTE - CDMA's LTE competitor, Ultra-Mobile Broadband (also known as 3xEvDO rev. C) was being developed by CDMA's main backer, Qualcomm, until 2008 when the company dropped support for UMB and threw its weight behind LTE.

    CDMA carriers include Verizon, Alltel, Bell, Sprint, Telus, and US Cellular.

    Cellular data rates are divided by "generation." They roughly equate to each other like so:

    Second Generation (2G)
    GSM - GPRS
    CDMA - 1xRTT

    Intermediate (2.5G)
    GSM - EDGE

    Third Generation (as defined by the 3GPP/3GPP2) (3G)
    GSM - HSPA
    CDMA - 1xEvDO rev. 0/rev. A

    There are also advanced 3G technologies (3.5G)
    GSM - HSPA+
    CDMA - 3xEv-DO rev. B

    Fourth Generation (4G)
    CDMA - 3xEv-DO rev. C (UMB) (development discontinued)
    GSM - Long Term Evolution (LTE)
    WiMax
    Last edited by isaacleese; 03-08-09 at 10:08 PM. Reason: Edited for spelling, clarity, and designation of different data standards by generation (thanks, MarcusAurelius!)
    03-08-09 06:50 PM
  2. saintj's Avatar
    Very insightful.... Can you explain what \'s going on with sprint and clearwire moving towards 4g ?
    03-08-09 07:11 PM
  3. isaacleese's Avatar
    Sprint and Clearwire are using a technology called WiMax. WiMax stands for Worldwide Interoperability for Microwave Access, and was actually designed as a last-mile technology to deliver broadband Internet access from the ISP NOC to the subscriber's premises. It was designed as a replacement for cable and DSL, not as a cellular radio standard. It has a lot of hurdles to overcome to actually be a competitor to LTE, not the least of which is lack of support - Sprint and Clearwire are the only service providers pushing WiMax here in the States. Every other carrier in the US, as well as most worldwide, have committed to LTE. The other main roadblock to WiMax is that it uses a high frequency - 2.5GHz - which has poor range and building penetration (lower frequencies, like the recently-auctioned 700MHz and currently-used 800/850MHz frequencies) have much better range and penetrate buildings and basements much better.

    Basically, WiMax will probably replace DSL and cable as fixed broadband connections, and LTE will replace the current GSM and CDMA wireless standards.
    03-08-09 07:30 PM
  4. Heresy's Avatar
    Great info in both your posts isaac. Thanks.
    03-08-09 07:53 PM
  5. MarcusAurelius's Avatar
    Great work. This should be stickied (especially in the Storm forum), and you should probably equate both HSDPA and EVDO as part of the 3GPP so people understand that EVDO is a 3G technology.
    03-08-09 08:46 PM
  6. hossra's Avatar
    Great post. With respect to WIMAX, keep away. Clearwire will be dead within 1 year. The investors have already written off their $4B investment and, trust me, spending inside is not matching the economy or developing business.

    Posted from my CrackBerry at wapforums.crackberry.com
    03-08-09 08:56 PM
  7. ilovemileyyy's Avatar
    I think they should all make one big happy family. It would be easier for everyone.
    03-08-09 09:37 PM
  8. isaacleese's Avatar
    Great work. This should be stickied (especially in the Storm forum), and you should probably equate both HSDPA and EVDO as part of the 3GPP so people understand that EVDO is a 3G technology.
    Will do.

    I think they should all make one big happy family. It would be easier for everyone.
    LTE, with its broad vendor and carrier support, looks to be accomplishing preceisely that.
    03-08-09 09:55 PM
  9. pltaylor's Avatar
    "The breakdown between GSM, CDMA, and WCDMA. GSM owns the world with 81% of the worlds mobile subscriptions. CDMA has a marginal 10.28%, which explains why many CDMA devices come out months if not years after their GSM variants."
    03-08-09 10:02 PM
  10. St13fL3r's Avatar
    Wow great break down!!
    03-08-09 10:03 PM
  11. BlackBerry Guy's Avatar
    Great writeup. Hopefully all the GSM boys out there will now realize "3G" is not a GSM only thing.
    03-09-09 12:05 AM
  12. zdkaram's Avatar
    well then if clearwire wil have a short lifespan, what will that do to sprint?


    What is better...CDMA or GSM....as far as speed, what the future holds etc?
    03-09-09 12:52 AM
  13. bx2md's Avatar
    this is great very full of knowledge
    and should be post as a must read
    03-09-09 01:02 AM
  14. isaacleese's Avatar
    well then if clearwire wil have a short lifespan, what will that do to sprint?


    What is better...CDMA or GSM....as far as speed, what the future holds etc?
    Sprint has expressed interest in LTE. They're going to hedge their 4G bet.

    The future is GSM, since Qualcomm discontinued development of the UMB CDMA2000 standard. LTE is what the future holds.
    03-13-09 12:06 AM
  15. wp7pup's Avatar
    Thanks OP for the great info.
    11-25-10 07:52 PM
  16. topherpaquette's Avatar
    Good post!

    Just would like to point out though that Bell and Telus are not just CDMA carriers as they have launched a shared HSPA network since Nov. 2009.

    Posted from my CrackBerry at wapforums.crackberry.com
    11-25-10 08:18 PM
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