Can someone please explain to me why they're referred to as GSM and CDMA...

[zorahk]

If they're not?

While the ATT iPhone does have a GSM compatible chipset, it's primarily a UMTS device, which is actually W-CDMA or FOMA.

While the Verizon iPhone is CDMA, it's actually CDMA2000/EV-DO.

So why do people refer to them by GSM or CDMA when that's not really what we're talking about here?

This can lead to comprehension issues, especially when discussing countries like Japan.

Japan doesn't support GSM. Japan does support UMTS, which is W-CDMA, which is FOMA. Japan does not have widespread support for CDMA2000 or EV-DO, which is what the verizon iPhone uses.

So in reality, shouldn't we be referring to these as the UMTS/W-CDMA and CDMA2000/EV-DO models?

I mean, in reality, they are both CDMA phones. One is W-CDMA, and one is EV-DO.

 

[jav6454]

Because they still fundamentally are. The iPhone is a GSM device with UMTS capabilities. On Verizon is happens to be a CDMA device with EV-DO flare thrown in.

Also, it's easier to refer to them as GSM and CDMA as all other wireless tech derives from them.

It's like trying to call 5-10W oil its actual name (long a$s name) when in fact people just know it as oil.

 

[Small White Car]

Feel free to stop using NASA, GEICO, & U.S.A. while you're at it.

The rest of us prefer to shorten long names, though, so that's what we'll keep doing. Accurate? Not as much, but it's faster and it still gets the point across.

If I say GSM iPhone and CDMA iPhone and you know what country I'm in then you know which ones I'm talking about. So look...I saved time and you still understood what I meant. Everybody wins.

 

[Applejuiced]

Not many people use those names or even have a clue what UMTS/W-CDMA or CDMA2000/EV-DO wireless tech is.
To be honest some people dont even know what GSM and CDMA is or their differences
They usually can tell the difference when a cellphone takes a simcard or not and that is about to change soon anyway with LTE

 

[zorahk]

Because they still fundamentally are. The iPhone is a GSM device with UMTS capabilities. On Verizon is happens to be a CDMA device with EV-DO flare thrown in.

Also, it's easier to refer to them as GSM and CDMA as all other wireless tech derives from them.

It's like trying to call 5-10W oil its actual name (long a$s name) when in fact people just know it as oil.

The problem is UMTS IS CDMA, it's just W-CDMA. So saying that one iPhone is CDMA and the other is not is misleading, because in fact they both are, it's just they are different implementations...one W-CDMA and one EVDO

They usually can tell the difference when a cellphone takes a simcard or not and that is about to change soon anyway with LTE

W-CDMA = UMTS = SIM card


Essentially, by saying one is GSM and one is CDMA, you are referring to 2G technology to reference a 3G chipset.
The 2G iPhone was an actual GSM phone. It was not sold in Japan where there is no GSM network.
The 3G, 3GS, and 4G were, because they are W-CDMA phones and that is the standard in Japan.

See why this is confusing?

 

[Daveoc64]

I mean, in reality, they are both CDMA phones. One is W-CDMA, and one is EV-DO.

W-CDMA is very unlike CDMA2000 so that comparison doesn't work.

The main problem with any set of names is that people will inevitably misuse them.

Some people think all 2G networks are "EDGE" or that "EDGE" is providing them with 2G voice calls.

 

[kdarling]

Using "GSM" and "CDMA" is mostly USA shorthand. ("UMTS" is shorthand for "UMTS-3G".)

In other parts of the world, people are more prone to talk about GSM and UMTS, and to understand that one system is 2G and the other is 3G.

They also seem to understand that UMTS is tacked onto GSM networks, but is a totally different radio system. In some countries, like Korea, UMTS is tacked onto legacy CDMA2000 networks instead. UMTS is not dependent on legacy GSM and can even operate standalone:

Many here might not remember that when UMTS was first deployed, there was the same kind of confusion as now with LTE. People were worried that the networks would flip entirely to UMTS and drop GSM support. They worried that dual-mode handsets would cost too much, or use too much battery. Global UMTS handsets also had to deal with each world area having different frequency bands available, and that took a while to sort out.

 

[LIVEFRMNYC]

GSM = Sim Card
CDMA = No Sim

That's all I need to know at the moment. Don't really want to use every letter in the alphabet to describe something.

 

[rdowns]

wgas?

 

[ikaveh]

cdma modulation is done by digital pulses. in cdma your voice is modulated by a scrambling code. in GSM the date of your voice is only transferred to a higher frequency band ie 900 MGHz or 1800 MGHz. in general gSM is more simple to implsement thats why its more popular worldwide.

 

[Applejuiced]

GSM = Sim Card
CDMA = No Sim

That's all I need to know at the moment. Don't really want to use every letter in the alphabet to describe something.

Lol
That pretty much sums it right.

 

[MacDawg]

Most people have no idea what this conversation is even about
The only letters they care about are ZOMG

As in... ZOMG!!!!11 I got my iPhone!!!!11

 

[jmmo20]

cdma modulation is done by digital pulses. in cdma your voice is modulated by a scrambling code. in GSM the date of your voice is only transferred to a higher frequency band ie 900 MGHz or 1800 MGHz. in general gSM is more simple to implsement thats why its more popular worldwide.

I'm sorry but what you just wrote in those sentences make no sense at all.

digital pulses? cdma voice modulation and scrambled code? in gsm voice date? transferred to a higher freq (higher than what? TV and FM? O_O)

seriously.. I just see 4 sentences without any conection among them whatsoever.

 

[Tarzanman]

Most of the people on this thread have absolutely no idea what they are talking about.

The way that "GSM" and "CDMA" are commonly used by most people is incorrect. They use it to refer to the 'languages' that AT&T, Verizon, Sprint and T-mobile uses for their radio networks.

The correct terms would be UMTS (AT&T/T-mobile) and CDMA-2000 (Verizon, Sprint).

Back in the 2G days, this was the 'easy' way to differentiate between these two standards... but nowadays it is confusing because CDMA (code division multiple access) is a protocol/technology used by all cell phone radio networks

 

[Daveoc64]

Back in the 2G days, this was the 'easy' way to differentiate between these two standards... but nowadays it is confusing because CDMA (code division multiple access) is a protocol/technology used by all cell phone radio networks

No it's not.

You clearly don't know what you're talking about.

UMTS uses W-CDMA as its air interface - that doesn't mean that it's remotely like CDMA2000. Trains and cars both have wheels, but they're very different.

The correct terms would be UMTS (AT&T/T-mobile)

It would be more accurate to say that AT&T/T-Mobile run a tightly coupled GSM/UMTS network.

 

[zorahk]

GSM = Sim Card
CDMA = No Sim

That's all I need to know at the moment. Don't really want to use every letter in the alphabet to describe something.

Thats not correct though, because phones that don't support GSM but only
w-CDMA still use sims.

 

[Rodimus Prime]

No it's not.

You clearly don't know what you're talking about.

UMTS uses W-CDMA as its air interface - that doesn't mean that it's remotely like CDMA2000. Trains and cars both have wheels, but they're very different.

In the finer points yes UMTS W-CDMA is different than CDMA2000. But he was talking about them in more general sense.

GSM was a TDMA set up and it transition over to a CDMA a set. This is part of the reason why Verizon had such a wide spread 3G network so quickly as it was more of a software update for them than a hardware like AT&T. AT&T towers were not optimised for CDMA set up which has a shorter range than a TDMA set up. Apple made it worse because AT&T told them that the 3G chip they were using would not work as well with AT&T network because of the tower placement. Apple of course did not listen and AT&T took heat for it.

 

[Tarzanman]

Thats a laugh. Why don't you get back to me when you've spent 2 weeks poring over a NOLS manual.

CDMA stands for code division multiple access. Specifically, a spreading code that the NodeB assigns to each UE communicating with it.

Now, go ahead and tell me which 3G carrier doesn't use CDMA as part of their protocol.

Hmm, how about the one of us who *hasn't* pushed scripts from the CLI of a UMTS RNC just stays quiet?

No it's not.

You clearly don't know what you're talking about.

UMTS uses W-CDMA as its air interface - that doesn't mean that it's remotely like CDMA2000. Trains and cars both have wheels, but they're very different.



It would be more accurate to say that AT&T/T-Mobile run a tightly coupled GSM/UMTS network.

 

[smithrh]

Sadly enough, I've seen so much error and misconception here over how cellular infrastructure works and how it is set up that I've basically given up on making corrections.

This thread - unfortunately - is another error-fulled episode.

if anyone who has an interest in understanding how wireless networks are set up and how they work and how they are operated should know this: this isn't the place to learn these things.

 

[Daveoc64]

Thats a laugh. Why don't you get back to me when you've spent 2 weeks poring over a NOLS manual.

I mainly objected to you telling other posters that they "have absolutely no idea what they are talking about" when you completely miss out the fact that GSM is still an important part of these networks. Millions of customers will only be using GSM - I simply don't think it's right to tell people that the term "GSM" shouldn't be used.

As for the differences between UMTS and CDMA, I didn't agree with your statement ("Back in the 2G days, this was the 'easy' way to differentiate between these two standards... but nowadays it is confusing because CDMA (code division multiple access) is a protocol/technology used by all cell phone radio networks"

As I said, that's just the air interface. I doubt any users care or notice that. It's not particularly common for people to talk about a W-CDMA phone (although it happens in some places).

I'll admit that I'm only a Computer Science student and cellular telephony is purely a "hobby" of mine, but I've read enough books about mobile networks.

 

[macsrcool1234]

The amount of abbreviations in this thread make my eyes bleed.

 

[ikaveh]

I'm sorry but what you just wrote in those sentences make no sense at all.

digital pulses? cdma voice modulation and scrambled code? in gsm voice date? transferred to a higher freq (higher than what? TV and FM? O_O)

seriously.. I just see 4 sentences without any conection among them whatsoever.

maybe I shouldnt post here as I thought it was a technical question about how these 2 systems work. and I dont think it helps to answer your questions as you will probably understand nothing, again.

 

[Tarzanman]

...and like most CS majors I went to school with, your grasp of anything beyond of how to compile a program is lacking.

I probably spent more time fixing CS majors' computers than any other major when I was in college. Hardware certainly isn't their strong point.

As I said, that's just the air interface. I doubt any users care or notice that. It's not particularly common for people to talk about a W-CDMA phone (although it happens in some places).

I'll admit that I'm only a Computer Science student and cellular telephony is purely a "hobby" of mine, but I've read enough books about mobile networks.

 

[yg17]

GSM = Sim Card
CDMA = No Sim

That's all I need to know at the moment. Don't really want to use every letter in the alphabet to describe something.

Not quite. http://en.wikipedia.org/wiki/Removable_User_Identity_Module

...and like most CS majors I went to school with, your grasp of anything beyond of how to compile a program is lacking.

I probably spent more time fixing CS majors' computers than any other major when I was in college. Hardware certainly isn't their strong point.

True that. I worked at a university's IT department, and they had a large CS program there. The CS students and teachers were good at coding, but god help them if they had to set up a rule in Outlook or connect to a network printer.

 

[Daveoc64]

At this stage I'm going to point out that the UK's University system is VERY different to the US and that the course content is also incredibly different.

For starters we don't even have "Majors".

I don't know anyone on my course that couldn't set up a network printer or configure Microsoft Outlook.

A very large part of the required course content covers hardware.

I stand by what I posted earlier and I've yet to see you actually prove me wrong. You've merely attacked the fact that I'm a student, rather than actually posting anything to back up why you think I'm wrong.