AT&T verses Verizon.  Which is better?  Seems like a simple question, right?  Well that’s not really the question you really need to be asking.  The real question (at least for now… more on that later) is: What are you doing with your phone?

“My phone?” you ask, “It’s a phone… I make calls on it right?”  For most of us it’s not that simple.  A phone isn’t just a phone anymore.

Some background.  Currently AT&T (also T-Mobile) use GSM while Verizon (also Sprint, Virgin & other smaller providers) use CDMA.  You might also have heard these called 2G (CDMA) & 3G (GSM).  There are a huge difference in the way the current versions of these two technologies handle cell towers. The easiest way to picture it is to imagine swinging between them.

CDMA handles cell towers very cautiously.  As it sees the next tower approaching it reaches out and grabs onto a cell signal hanging from it.  This makes it connect a bit slower but the benefit is that as you move about, you are less likely to drop you call.  The phone makes sure it has a spot and a solid hold on that next cell tower before letting go of the previous one.

Current GSM networks, however, are a bit more fast and loose with their swinging.   As it sees an upcoming tower it jumps off to grab a signal.  This gives it the advantage of allowing fewer people on a tower at once and making the cell phone connect much faster when hopping towers.  As you can guess, there is a bit of a down side.  If there are no free spots on that tower… you drop your call.

If this is the case, why choose GSM?  If CDMA handles phone calls better, why does GSM exist?  The problem is the modern cell phones aren’t just a phone anymore.  Surfing the web, applications, documents, video calls, texting…  all this is beyond what the original phone networks were originally designed to carry.

Because the current generation of CDMA is an older technology it puts all the different information bits on different channels that it sends to the tower.  Phone calls come first, everything else second, third, etc.  On CDMA the phone not only makes sure that it’s always connected, but also that everything else is secondary to the phone call.  Current GSM?  It’s newer technology.   It pushes everything through one packet which gets decrypted on the other side.  Voice or data, it doesn’t matter.  Drop a cell tower?  Data doesn’t care.  It will just reconnect to another tower.  Data doesn’t care how the data gets from point a to b, just that it gets there.  It’s only the phone call that will suffer.

So were does this put the original question? If you are the type of person who lives on the phone… yet somehow doesn’t manage to make actual phone calls – GSM is for you.  It will allow faster data speeds and even allow you to talk and surf at the same time, at the expense of more dropped calls.  If you either use every minute o your phone plan, or need a much more reliable phone system – CDMA is for you.  It will keep you from dropping most of your calls, just at the expense of a phone call cutting off your streaming radio and slower data speeds.

Now all of this comes with its caveats.  If all you do is make phone calls, but you travel the world GSM is again your best bet.  Most of the world is on a some type of GSM network.  CDMA has a lot of coverage in North America, but not so much elsewhere.  Also if you tend to change your phone often, GSM also has the advantage of using a SIM card, so swapping that out to different phones becomes much easier than with CDMA phones.  Inside a building?  CDMA (and technically EDGE) handles it better, but causes interference with speakers.  Then there’s quality of service itself, which I’m not even going to get into. And then on top of this, in a year or two the differences will be moot.  All the major companies are moving forward with Wi-Max and LTE networks.  But that’s a different post altogether.

TLDR – GSM = more dropped calls, faster data.  CDMA = fewer dropped calls, slower data.