How 2G, 3G and 4G Cell Phone Networks Work

Chris Polette. I'm an editor here at how stuff works dot com and sitting next to me as usual as senior writer Jonathan Stricklandoha. All right. I wasn't expecting that. I know you weren't. All right, well, so so why the aloha? No reason? I just like to change it up every now and then. All right, and multicultural kind of guy. I figured you were thinking of pineapples. Now, I think I'll end this with mohallow. I think Mr Calicanus will have a word to save. Why don't we

move on to our topic? All right, So today we're going to talk about communications, actually long distance. Maybe maybe somebody will be saying aloha and mahala to you. Yeah, perhaps some roaming. Yeah, because we're gonna talk about cellular communications. We've had a lot of emails come in about, you know, discussing things like the two G network, the three G network,

the uh, the the eagerly awaited four gene network. Uh kind of too, sort of demystify these terms, kind of explain what they mean, and uh, why you should be concerned about what kind of phone you have or if you should be concerned. Um, and yeah, some of this came from just from the last year's release of the iPhone three G, which caused a lot of confusion among I would say, lay people who aren't really familiar with

the whole two G three G thing in the first place. Right. Well, yeah, I mean it's really not all that surprising when you think about it, because Apple for a while there um was releasing new generations of IBM S power PC processors, and they'd have they had the G three and the G four Max. Right, So so you know, it makes sense that people would be a little surprised. Um. You know, I actually had somebody right in and say, hey, that's a picture of the three G iPhone, not the second

generation iPhone. Well, the second generation, second generation iPhone is the three because it's not three G, it's G three or wait two right, G two? So yeah, alright, so here's where this whole confusion. See even we get confused, and it happens to the best of us. Um yeah, so yeah, the second generation iPhone is a three G phone. And that's because the three G does not refer to the phone's generation, but rather the the technology, the cellular

technology that phone communicates across right right. As a matter of fact, people are wondering what they're rumors right now swirling about the next generation iPhone, and they're wondering what to call it because it won't be the three G G three iPhone it that would just be silly. And then they're calling it the G four anyway, Well, it's not really a fourth generation iPhone. Why don't we just call it Steve, Yeah, I think we'll be like that.

We'll just call it the jobs so um. So here, currently in the United States, we're kind of in a transitionary period where we're going from a two G network and into a three G network. Um. Three G coverage in the United States is is much better than it was this time last year, but it's still it's still one of those things that's growing, um city by city, And not every carrier has a three G network. Um.

This this is technology. I mean, it's stuff that you know, hardware and software have to be in place for these networks to work, and not all the carriers are are up to speed on that, at least not in the United States now. Granted, in other parts of the world they've had three G for a while now and UH. And there's certain parts of the United States where they've had it for a while, like San Francisco that you know who to thunk it, but other places just got it,

like within the last twelve months or so now. So the different generations, you can kind of divide them up by two different things. The technology G they used to transmit signals through the cellular network and the speed through UH that those signals have. You know, so like a two G phone is going to transmit data and UH calls at a lower speed than a three G phone. In general, it depends on the It depends on the technology too. It depends on the technology. It depends on

it actually depends on a lot of things. So we have to talk in a lot of generalities here, but let's let's break it down first. Like I was gonna talk about two G uh, they're there are two predominant technologies in the two G networks. UM. Most of the

world uses G s M, which is a UH. It's based off time division multiple access technology or t d M A right, right, So like Europe, Africa, Asia, a lot of these places they're using G s M. But in the good old US of A, we decided to kind of adopt another technology, UM and and some of the carriers are still using that, and that's called code division multiple access technology or c d M. A. That's right. Actually, if you're wondering where G s M came came from,

it's actually from A a French acronym. The a Confederation of European Posts and Telecommunications found of the group speciel Mobile in two and yes that's two. That's you know, twenty seven years ago, and they're the ones who basically developed the standard known as G s M. And then the acronym comes from them. Now for US RAT speaking folks as not speaking by that, I mean those who speak English or American. If you prefer UM G s M, we usually just go ahead and knock that out into

Global System for Mobile Communications. Yeah, so it's not the the the true origin of the acronym, but hey, that's how we Americans like to do things, gosh darn it. So anyway, these two different technologies, they transmit information across radio signals in different ways, and because of that, they're not automatically compatible with one another. In fact, they're they're incompatible. So if you have a G S M phone, you can't necessarily switch to a C d M A network.

So if you don't have any G s M coverage in the area you're in, you're kind of stuck. And that was one of the big problems of the US for a really long time was that a lot of the rural areas had C d M A coverage but not G s M coverage. So if you started driving across the United States, you would find big patches of

areas where you had no service. Um. Since then, there have been some systems put in where you can use one phone over an other carriers network, but you usually end up having to pay some pretty big roaming charges um. At least until fairly recently, a lot of the phone carriers now I've realized that that tends to drive customers away, and so they've they've taken that into account. But yeah, and in in this case, it's still a matter of G s M phones using other GSM networks and c

d M A phones using other c d M A networks. Um. And if you're wondering sort of in a in a broad path, which camp your provider falls into. Um, if you're using Verizon Wireless or Sprint, next heel, Um, those are c d M A and uh T Mobile and a T and T are using g s M. Um. You can also find out if you if you are blindfolded and or you know, somebody had rubbed off all the markings from your phone and they're not going to do that. That's why they subsidize your phone. They put

their brand all over it. Um. But say you had to look at the back of a phone that didn't have a brand and go, how would I find out which one this is? If you were to take the battery out and look underneath, if it's got a simcard, that's as phone. Yeah. The nice thing about g S M phones is that if you if you have multiple simcards and you have a different simcard for every you know cell phone carrier, you can switch those out and

then you're not even roaming anymore. Like if you move from one carrier's GSM network into another and you happen to have a simcard for that carrier, you can switch them out and you're you're just fine. Um. There's still some problems if you are traveling overseas because they transmit cellular information on different frequencies. So if your phone does not is not capable of transmitting in the same frequencies as the carrier around you uses, you're still out of luck.

It's just not going to be able to communicate with the network. That's uh. That's what you see when you're looking at phone specs are looking for a new phone and you see triband or quad band, Um, that's what they're talking about. Or if you see the phrase world phones, that's basically what it's talking about. For GSM. There are actually four uh frequencies that I'm aware of that are

used in different places around the world. Um. And the more frequencies you use, I mean they're still using g s M, but you know, you may or may not find a signal. And if you're using c d M c d M A, you're gonna have a much more difficult time finding a signal. Yeah, especially yeah, traveling abroad, because like like we said, c d M A is one of those technologies that really got a foothold in the United States and pretty much everywhere else adopted G

s M. You may wonder why that is. It's because a lot of the European countries, uh, the governments of those countries mandated a specific technology, and in the US that's generally considered kind of anti competitive, and so the U S takes a lass a fair approach and they decide not to They say, well, you know, we're not gonna mandate which one is used, which sounds good except for the ends up being kind of confusing for the consumer.

To make matters even more confusing. You may have seen c d M A or G s M under other code names like E V d O and EDGE. Well, those refer to the different kinds of technology, and they're actually different forms of three g r UM edges. One of them that's probably well known. UM. I think the first place I saw it once when they were starting to talk about the three G I phone and they

were saying, well, it will be compatible with the Edge network. Um, they talked about I remember reading articles about how T Mobile wasn't even on Edge yet, and that was one of the things with the uh the G one. You may have heard of this, This phone from HTC uses the Google Android operating system. I'm somewhat familiar with it. Yeah, yeah, well they that was one of the things, uh, you know that they did. But E V D O and

Edge are you know next well, theoretically next generation technologies. Yes, some might say two point five instead of three. Because here's the other thing is that when we're talking about these technologies, uh, there are organizations that are in place to try and standardize these technologies as best they can, but you're still talking about a range of capabilities, um, and so it gets kind of confusing. You know. You start seeing things like the two G speeds sort of

bleed into the lower end of the three G speeds. Uh. So then you might say, okay, well, this is really a two point five G phone or two point seven five G phone, because it's faster than a two G phone, but it's not as fast as what three G is supposed to be. Yeah, it definitely does not make life easier you know, to understand all this stuff, right, well, I mean, just to put some numbers behind it, EDGE, which is UM, the enhanced Data G s M environment.

We'll give you speeds of up to kilobits per second from what I understand, But that's on the road to what a lot of people are calling the true three G, which is Universal Mobile Telecommunication Servers or u MTS or is I like to call it. And uh, and that's two megabits per second. So um, you know that's that's about one and a half times faster. Actually now wait, never mind, it's like four times faster. Yeah, it's a

it's really fast compared comparatively speaking. And we should also go ahead and point out that these these really high end speeds, they tend to be ideals. You know, you don't it's very rare that you're going to actually encounter that on your own phone, especially if you're moving, If you are in motion, then you're going to experience lower speeds no matter which network you are, and you're not

going to have the ideal speed. And some of them you'll see, like in lab tests, they achieve speeds of blah blah blah, blah blah blah, that's because they're being still in a lab chair and not driving across town when you're having a conversation with a friend. And exactly it's in under ideal circumstances, which I don't know about you, but I am rarely in what I would consider ideal circumstances, unless I happen to be in Hawaii, in which case

I often do think I'm in ideal circumstances. The other the other three G technology besides the U M T S is a c d M A two thousand. Actually there are more than just the two, but those are the two main ones. And again this is another generation of the c d M, a technology which we can expect to see because the United States doesn't hold you know, it doesn't like go of stuff that easily. I mean, do you remember when we try to switch to metric

we're still actually we sort of gave up on it. Yeah, we totally gave up on it because Yeah, same sort of thing I think is going to happen here is that people who have who have this technology are not going to give up on it anytime soon. But um, I did read that a T and of course I read this at a T and T S website, So

take it. Take this however, summer story supply, but A T and T said that there are three G speeds range from three point six to seven point two megabits per second in the lapse and they expect that by the end of two thousand nine they'll have it up to twenty megabits per second. That's pretty fast. And um, that's not fast, no, not compared to four G. Yes, is that where you were going, right, I was going. But we we need to finish three G. I think

we're pretty much done. I mean we could talk about I guess next would be a long term evolution, right, yes, which is where we're getting into the four G. Yeah, that's long term evolution or LTT is the four G network. And uh speaking of your your reluctance to abandon technologies, it's kind of funny because the people who are moving to LTE are actually um sort of a hodgepodge of different people who are in different technologies now, UM A,

T and T and Verizon. One of them is GSM, the other is c D M A. Both of them are saying that they'll have uh LTE networks in place. Um by uh, well and I'm saying when they say networks, I'm thinking maybe not with a capital and network, maybe like New York and places they're they're usually in scaled rollouts. So well, I mean, hey, let's let's play a cell

phone tycoon for a minute. You know, you have you've built out this infrastructure that goes across the country more or less, and then you have to go update all that stuff, and you only have a limited budget. You know you're gonna hit the big places first where lots and lots and lots of people are UM and then move it out from there. So the thing is, though, that LTE will actually hit um a hundred megabits downstream

and thirty upstream. UM. It actually uses a form of t C P I P, which is uh the protocol over which the Internet travels, and it's gonna be a lot more like using an Internet network than cell phones use now. So it'll be a lot more familiar, is what I mean. The technologies are actually sort of and to use Jonathan's favorite word converging, Yes, it'll it'll look more like a WiFi set up than a cellular setup,

although it's not using WiFi. I mean that would that would be a nightmare to do that, because you would drop calls every time you walked fifteen feet. Now that that's true, but uh, you know it's it's rising and a T and T moving toward LTE and not another famous name, which is embracing a competing technology that we're all familiar with. It will never be rolled out. In my opinion, y Max and Sprint. Sprint is a big fan. They're they're teamed up with clear Wire. Actually admire the technology,

and I hope they roll it out. Didn't they talk about this back in two thousand four something along those lines. So wy Max, Yeah, that's that's supposed to be one of those last mile solution problem things where you you say, how can we deliver uh, Internet connectivity to that last mile, uh, the last mile to the customer wirelessly. So it's kind of like it's it's using a wireless technology that um some people call it WiFi on steroids, but that's not

really accurate. Um, it uses a completely different kind of protocol than WiFi. Uh, there are a certain number of open spots. Let's say, let's let's just kind of I'm going to use an example, kind of a concrete example, just imagine this to kind of get an idea of how why max works. Think of a round building that has forty doors, forty doorways, and as long as one of those doorways is open, you can get into that get in and out of that building, and get whatever

information you need in and out of that building. That's kind of the way why max works. Once you hit a certain number of of folks hitting that that y max server or actually tower, I guess you could say you gotta go somewhere else. So um, but theoretically you could serve information at incredible speeds to the people that you are allowing into that particular service. I'm kind of with Pullette here. I don't know that we're ever going

to see this because we've been promised it forever. I know there's certain cities that are rolling out y max networks, but yeah, it's um, it was supposed to be everywhere by now, and it just it hasn't arrived yet. UM. I think this goes back to the it's really expensive to roll out expensive, brand new technology to everywhere. Yeah, putting out a new infrastructure, whether you're talking about communications or transportation or you know, fuel or whatever. Anytime you're

talking about rolling out a new infrastructure. That's expensive because first of all, you got to figure out how you're going to incorporate it into the existing infrastructure, and then you got to build the darned thing, and you gotta troubleshoot, and you gotta make sure it works, and you gotta bring it online. And I mean, it's it's a big, big deal. It's not like, you know, you flip a

switch and suddenly everyone's on four G. Now. Um, I had read a report that said that, uh, that currently the expectation for widespread adoption of LTE in the US will will take at least until two thousand twelve. So um that would it would surprise me if we got there by two thousand twelve, considering how long it took us to get to three G. But let's hope springs eternal. I mean, the recession kind of also plays another nasty

card into this whole thing. Companies are suddenly worried more about staying in business than they are about innovating, So we'll have to see how that goes. Um. I did hear that if you're stationary and you're using a top of the line for G network, you could expect up to one gig a bit per second eventually, which is that's a lot of data that's really really fast, and that's the that's the point at which you're gonna start seeing, uh.

I think internet convergence versus you know, now you have DSL and cable, but at those speeds, so you know, that's beating out DSL and cable connections. Now even even the fiber optic connections are slower than that. And I've talked a lot about like netbooks converging with smartphones. I think at those speeds, you could really you see that happen,

because suddenly cloud computing becomes a really distinct possibility. You know, you don't connect to a WiFi network, you connect to a four G network, You're gonna have much faster speeds than you would with WiFi. So at that point, cloud computing becomes really really attractive because you as long as you have that guaranteed high speed connection, you can take

advantage of it. Yeah, that sounds good. I have nothing else about cellular phone networks, I know, Thank goodness, because you know what that means, right, And I can try and invent something real quick, hope. Sorry, it's time for listener mail. Today's listener mail comes from Simon. Simon says, Hey guys, Hi Simon, I was very intrigued by the podcast on expensive cables, although without much proof, I've always maintained that they are probably nothing but a big scam.

At least if you have an average entertainment system and non bionic ears. You might haven't come in the mail yet. I do have a couple of ments on the study with coat hangers. As you say, it's only five people, so obviously not too scientific, but it seems to me that if two out of five could tell the difference,

that might be a little bit more than just coincidence. Secondly, the fact that a coat hanger may produce the same quality of monster cables can be explained by the fact that it's made of a very thick wire, possibly capable of transmitting more information. I just did air quotes because he put quotes around that. So in that sense, a code hanger and a monster cable maybe better than regular cables. I love the podcast. Please keep up the great work. Thanks, Simon.

Great really appreciate that. Um I agree with you, a sample size of five is not scientific at all. You can't call that scientific. It was really more of an experiment, like in the very loosest sense of the word, not in the scientific sense. Um. As for as for uh, a a thick wire carrying more information, Uh, you know, yeah, heavier gauge wire is capable of carrying a higher charge.

I mean that makes sense. Um. But it also keep in mind that the the coat hangers had no shielding, so there was nothing to shield it from any interference, which is another one of the claims that high end cable UH manufacturers will make. They'll say this, these cables have a lot of shielding on them, and therefore the signal will be pure and you will you won't lose anything from the source to the destination. Yeah, that's true. And um, of course, the point is that not that

monster cables are complete under fraud. They're actually very good cables. It's just that, uh, most people say, well, lesser cables can handle the same treatment or are are as good in certain circumstances. So you know, it's not a complete right, you know, you're not wasting your money, it's just you're maybe you could probably spend less money, Yeah, you could, You can probably spend less money and get the the

experience that you really want. Um, you know, unless the experience you really want is to feel your wallet get lighter, in which case monster the way to go. Baby. Yeah. I mean if brand recognition is good for you, then yeah, it is a good quality product. Yeah. Alright, Well, now that we've managed to weasel out of that one, I think it's try to wrap this up. Remember, if you have any comments or suggestions or corrections, anything along those lines, you can send it to us text stuff at how

stuff works dot com. We have blogs up. You can go to how stuff works dot com and you will see the listing of the blogs on the right hand side. Please come and visit. Definitely leave comments. Chris and I both interact on those blogs. So if you have a burning desire to say, hey, I love your podcast, and by the way, you misspelled blah blah blah, you can do that and then we will hang our heads in shame. I never misspelled blah blah blah, and neither do I actually,

but you know you can other words. Yes, So please come to how stuff works dot com check out some of the articles there. We have plenty one cellular phones. Boy, I've got all the way through until the end. Cellular phones and UH and other subjects as well, and we will talk to you again really soon for more on this and thousands of other topics. Is it how stuff works dot com brought to you by the reinvented two thousand twelve camera. It's ready, are you