[eds817]

I am currently with T-Mobile USA and plan on switching carriers. My choices are AT&T, Verizon and Sprint. Since AT&T is GSM and the other two are CDMA I was wondering what are the major differences, pros & cons.

I know GSM uses a SIM card and CDMA does not.

Is one type of service better than the other? If so why?

ADDED: I am located in South Florida and travel is limited.



TIA

[vzinside]

*Grabs popcorn and waits for the flame war

[kbz1960]

I say it depends on how the service is where you're at and where you travel to. GSM does allow talk and surf at the same time but some phones offer that on LTE. I think CDMA penetrates thru buildings better. It really should come down to service.

[Xopher]

If you're looking at BB10, Verizon will use LTE, which also uses a SIM. I believe Verizon and Sprint both fall back to CDMA when LTE isn't available, and GSM on T-Mobile and AT&T. For the most part, phones are usually locked to the carrier, especially on CDMA where the phone's ESN is registered into their database. It's quite difficult to take a CDMA phone to another carrier. I'm not sure how the switch to LTE affects all that.

[valeuche]

Given that travel is limited as others have said it depends on the level of service in your area

That said, AT&T when on 3G on most phones will use a higher bit rate codec (AMR-WB) and call quality is noticeably better.

GSM is cleaner in that voice calls can be carried over 3G or edge or gprs, where as on cdma voice calls are only carried over 1xRTT. Neither carries voice over LTE yet.

The same standards body that came up with the gsm 3G came up with LTE - technologically it feels cleaner to be on a GSM/LTE network, but at the same time Verizon LTE is widespread now. Its not easy to find a place that has version coverage without LTE support now.

AT&T uses two LTE bands in some markets (4 and 14 iirc) and when each are 10 mhz wide would have higher capacity than Verizon with a single 10 mhz channel but that really means that AT&T might be able to sustain higher user counts in some places.

On the other hand, there is no inherent limit to the number of users that can be served by a CDMA tower, the limiting factor is physical. Also CDMA can do soft handover between towers and in fact a CDMA handset is usually signed in to multiple towers at once. GSM uses hard hand off and when that fails the call is simply dropped.

Its a mix. I personally like CDMA but we are at the point that either one is very good.

Sent from my Droid DNA

[ddlax22]

The poster above me really outlined it well, personally I like gsm not because I have AT&T but because gsm is more widespread and also because LTE evolved out of gsm technology. Also, if you have a choice between sprint att and verizon. Narrow it down to att and verizon.

[SEAWARRIOR]

The poster above me really outlined it well, personally I like gsm not because I have AT&T but because gsm is more widespread and also because LTE evolved out of gsm technology. Also, if you have a choice between sprint att and verizon. Narrow it down to att and verizon.

valueche, great breakdown,,, OP, do what's best for you but my experience w/ sprint has been good,,, when i first started w/ them customer service was good then it was lousy for a while & the last few years it's gotten much better,,, you will get more bang for you buck vs. verizon,,, i've also heard from friends that they have to call verizon every month to have erroneous charges removed from their bill,,, the plan i have would cost $30 more a month w/ them,,, call quality is excellent,,, go to each website & look @ the coverage maps,,, that might be helpful also...

[web99]

My advice is to go what works best for you. In my case, I do a lot of international traveling and GSM is more widely used among the international carriers and I usually change SIM cards. So that option works best for me.

Posted using CrackBerry App on BB10

[rjkolo]

I would see which carrier has what type of coverage in your area and go from there. I live in a slightly rual area and VZW does not work very well there, but ATT has their H+ there with full coverage so the choice is easy for me. I have friends with VZW and they really don't complain about anything...except when they come to my house and have no coverage. See which plan will be cheapest for you from what carrier, what fits you the best.

[kg4icg]

Because of Qualcomm the 3g SVDO is a thing of the past since CDMA devices do it now. GSM does not have a advantage over CDMA in voice quality, it is the opposite. CDMA devices once reported stolen can not be ever used again. Once the esn is black listed, the phone is nothing but a brick. By the way, I have a CDMA/GSM/LTE phone on Sprint waiting for what comes out next from Blackberry on said network.

[FrankPCS]

You shouldn't worry to much between CDMA or GSM. Those networks are pretty much built out and pretty effective to the point their differences are negligible. It's all about LTE now. Verizon covers more area. AT&T is not too far behind and Sprint is barely getting out of the gate.

[randall2580]

It seems inside the USA it might not matter. If you ever step foot outside, a CDMA phone is a brick.

[valeuche]

Because of Qualcomm the 3g SVDO is a thing of the past since CDMA devices do it now. GSM does not have a advantage over CDMA in voice quality, it is the opposite. CDMA devices once reported stolen can not be ever used again. Once the esn is black listed, the phone is nothing but a brick. By the way, I have a CDMA/GSM/LTE phone on Sprint waiting for what comes out next from Blackberry on said network.

What codec does CDMA use for voice on 1xRTT? In terms of bit rate and frequency transfer I remember that AMR-WB > the CDMA codec > regular adaptive multirate but I don't remember very clearly what the actual CDMA codec was or what it's MTF / FTF results were like. My apologies if I was wrong about voice quality. Though it doesn't make sense, at very best CDMA has available only 1.25 MHz for voice and dividing it among an equal number of users it would seem that GSM 3G (HSPA+) has much, much more bandwidth available - 5 MHz and at 64QAM.

Edit:
So AMR-WB (GSM) provides a mode as high as 12.65 Kbps compared to EVRC providing 8.8 Kbps at the highest mode. It is difficult to imagine that EVRC (the CDMA codec) would be able to outperform a codec providing for 50% higher bitrate, particularly since AMR-WB is a newer codec as well.

[FrankPCS]

It seems inside the USA it might not matter. If you ever step foot outside, a CDMA phone is a brick.

Depends. Sprint and Verizon offers world smartphones you know. I managed fine outside the US with my CDMA BlackBerrys...Berries(?)

[valeuche]

Because of Qualcomm the 3g SVDO is a thing of the past since CDMA devices do it now. GSM does not have a advantage over CDMA in voice quality, it is the opposite. CDMA devices once reported stolen can not be ever used again. Once the esn is black listed, the phone is nothing but a brick. By the way, I have a CDMA/GSM/LTE phone on Sprint waiting for what comes out next from Blackberry on said network.

Also to add I have a Droid DNA which has a Qualcomm chipset, but it can only do data and voice at the same time when it is on LTE (using LTE and 1xRTT at the same time), when on 3G/EVDO it can only do the voice call, no data

[valeuche]

It seems inside the USA it might not matter. If you ever step foot outside, a CDMA phone is a brick.

I was only last week using a droid DNA in Afghanistan, UAE and Amsterdam. No problems (though it had switched itself into GSM mode). In Ukraine last year i was using a thunderbolt on CDMA without problems. CDMA is present in something like 40 countries.

[FrankPCS]

Also to add I have a Droid DNA which has a Qualcomm chipset, but it can only do data and voice at the same time when it is on LTE (using LTE and 1xRTT at the same time), when on 3G/EVDO it can only do the voice call, no data

SVDO needs to be enabled on the device I thought.

[valeuche]

SVDO needs to be enabled on the device I thought.

I didnt have to do anything on the thunderbolt for it to work. If it is enableable on the DNA it's not obvious how to do it.

[valeuche]

I am currently with T-Mobile USA and plan on switching carriers. My choices are AT&T, Verizon and Sprint. Since AT&T is GSM and the other two are CDMA I was wondering what are the major differences, pros & cons.

I know GSM uses a SIM card and CDMA does not.

Is one type of service better than the other? If so why?

ADDED: I am located in South Florida and travel is limited.



TIA

Probably it should be added that there is no unlimited plan for Verizon or AT&T, but avoid sprint if you aren't in a network vision area until network vision is deployed there.

[randall2580]

Depends. Sprint and Verizon offers world smartphones you know. I managed fine outside the US with my CDMA BlackBerrys...Berries(?)

Yes sorry there are exceptions to this rule of course, the flagships have GSM SIM card slots that in theory at least allow you to travel - but you have to be careful to get the phones that travel, because I believe it's the majority in the Verizon store do not, at least not well.

[FrankPCS]

I didnt have to do anything on the thunderbolt for it to work. If it is enableable on the DNA it's not obvious how to do it.

Ya, i meant that the manufacturer can offer SVDO and the carrier can either agree or disagree to have it as a feature. So even though your DNA has a Qualcomm chip its up to the manufacturer and carrier if they want to support it.

[distributor1]

If you are talking about travelling depends on where you are going Europe and Latam, no CDMA to fall back on. I like GSM as I can switch sim cards depending on the country and what I need to do. I live part time in Colombia so when there I just switch to a local sim and the BB keeps on chugging without donating $2.00 a minute to TMO (note, need an unlocked BB, which the codes are really easy to get)

[ghostface147]

If you don't travel much and when you do travel it's only in the US, then stick with Verizon.

[FrankPCS]

Yes sorry there are exceptions to this rule of course, the flagships have GSM SIM card slots that in theory at least allow you to travel - but you have to be careful to get the phones that travel, because I believe it's the majority in the Verizon store do not, at least not well.

i dont follow Verizon much but i believe the majority of their smartphone lineup offers GSM for international use. Sprint on the other hand has lost its way with its international lineup...especially since they started embedding LTE SIMs in their recent phones - but plan to offer removable SIMs again later this year.

To the OP I'd take a wait and see with Sprint since they are at the point of throwing things against the wall to see what sticks.

[scorpiodsu]

1) Just really be concerned about service where you need it most
2) If looking for flexibility in terms of device choice, then GSM wins here. Usually have more variety and overseas options if not available locally.
3) Supposedly CDMA is known for better call quality and reliability. Of course it varies but it is said that if all things are equal CDMA wins.
4) GSM is supposedly better on battery life. I'm sure this varies among devices but if all things are equal.....
5) CDMA at some point will go dark. I read somewhere that they are projecting by the end of the decade no one will be using CDMA for wireless.

I've never chosen networks by wireless technology. It's always been cost vs coverage for me.