LTE, HSPA, EvDO Network Types - … HSPA, EvDO Standards 30 LTE, HSPA, EvDO Standards Wireless data...

LTE, HSPA, EvDO Network Types

Table of Contents

LTE, HSPA, EvDO .............................................................................................................................. 2

LTE, HSPA, EvDO Standards ............................................................................................................ 3

LTE, HSPA, EvDO – Governing Body ................................................................................................ 6

LTE, HSPA, EvDO – Network Types ................................................................................................. 8

LTE, HSPA, EvDO Signaling .............................................................................................................. 9

LTE, HSPA, EvDO Hardware ........................................................................................................... 19

Summary ....................................................................................................................................... 21

Notices .......................................................................................................................................... 25

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LTE, HSPA, EvDO

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LTE, HSPA, EvDO

**029 LTE, HSPA, and EvDO. What are those, other than really cool letters? I got people already looking at the next slide. Right? What industry are these coming from? This is cellular, right? This is 3G and 4G cellular service.

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LTE, HSPA, EvDO Standards

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LTE, HSPA, EvDO Standards

Wireless data standards used by mobile phone providers• Long Term Evolution (LTE)• High Speed Packet Access (HSPA)• Evolution Data Optimized (EvDO)

Allow customers to access data services from their handsets

LTE HSPA EvDOSpeed (down)(Theoretical) (up)

300 Mb/s75 Mb/s

88 Mb/s 22 Mb/s

4.9 Mb/s1.8 Mb/s(per carrier)

Technology Evolution

GSM UMTS CDMA

Network IP IP IPType 3G transitional

(LTE Advanced is 4G)3G transitional 3G transitional

**030 And why are we talking about that in here? Because it's another data standard, correct? There was a time when we didn't really think of our phones as data devices. And depending what your age is, you may not yet think of a phone as a data device, but how many people have received somebody sending you a video or sending you a photo from their cell phone? We now get our email on our cell phones, right? They are data devices, and the whole cellular network is another infrastructure that you can move data on.

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The good news is the cellular infrastructure does not operate on 2.4 GHz. Anybody know why? Student: You have to pay money to buy the spectrum. Joe Mayes: Yep. Eventually, yeah. And it's one of the few times the FCC has ever auctioned spectrum. Usually most spectrum is given away by the FCC, as long as you operate in the public interest. TV stations don't pay for their channels, but they must operate in the public interest or they can pull the license. That's why they have periodic license reviews, and that's why you'll see stations do, "If you have"-- "Our license is up for review, and if you want to comment, send your comments to somebody- somebody at the FCC." So, Long-Term Evolution, High-Speed Packet Access, or Evolution-Data Optimized, EvDO. You can see the data speeds there-- 300 megabits, 88 megabits, 4.9 megabits, per carrier. And then the technology evolution of GSM, Global Systems for Mobile; EMTS, or CDMA. CDMA is a very interesting technology. With CDMA you can have multiple stations operating on the same frequency at the same time, and they actually embed what's called a Walsh code on each signal so the two receivers can tell which one they should listen to and which one they can't listen to. When the company that developed this technology was beginning to put it together, all kinds of engineers

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said, "This will never work," including engineers from very prestigious companies. Said, "This will never work." Guess which company went forth and developed it anyway. Student: Qualcomm. Joe Mayes: Qualcomm. And the fact that we know about Qualcomm means, by golly, it did work, and they made it work. Yep. CDMA-- Code Division Multiple Access. CDMA. Have multiple people broadcasting at the same time on the same frequency using something called a Walsh code. It's interesting to read about if you like technology. So I would recommend that you go out and read separately because we're not going to delve into it in this class, but it's an amazing little technology to see how CDMA actually works.

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LTE, HSPA, EvDO – Governing Body

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LTE, HSPA, EvDO – Governing Body

3GPP – 3rd Generation Partnership Project • Group of providers and manufacturers who work to define 3G

cellular services, strategies, and policies worldwide— Focused on GSM networks

3GPP2 – 3rd Generation Partnership Project 2• Focused on CDMA / CDMA2000 networks

**031 So, one of the reasons it comes up in here is because we really do now have an active competition in the business world and in the world at large between which technology am I going to listen to-- right?-- which technology am I going to use. How many people have phones that have 3G and 4G on them? And also have 802.11, correct? You can connect to an access point or you can connect to a cellular network. What makes you choose one over the other, by the way? Student: If you're going to pay for data or not.

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Joe Mayes: Whether you're paying for the data or not-- that's a big one. Student: You're going outside the country . Joe Mayes: If you're going outside the country, because then either you can't connect or the data rates are tremendous. What'd I see? I was just seeing that ad. I think one of the-- I'll leave the carrier name off, but one of the carriers was selling 400 megabits of data, foreign data, for 25 dollars. Twenty-five dollars for every 400 megabits when you went into Europe. And around here, we get upset when we have to pay 25 dollars for 4 gigabits, right? Or gigabytes. So, at the same time, in the back of the room, you talk about sometimes you're in a hotel and the wireless environment in the hotel is so clogged up that people will put out their iPad or whatever and make a local connection and say, "I'm done with this 802.11 network. I'm going to go over to my cellular network."

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LTE, HSPA, EvDO – Network Types

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LTE, HSPA, EvDO – Network Types

Similar to cellular voice calls• The handset communicates with a base station on the antenna

tower, which relays the data signals to the provider.

Network setup is similar to cellular voice calls.• Subscriber identification numbers are compared to the provider’s

authorized customer’s number and allowed to communicate with the base station dependent on that decision.

Base Station

Internet

Service Provider

**032 So. Network types. These systems, I think we all know how they operate. There are bay stations, cell towers, right? And a cell tower is connected back to a service provider, who connects back to the internet, and basically they're just an alternate ISP, internet service provider. You can treat them just like ISPs. I do work on Cisco routers, and Cisco routers can take cellular cards in the routers to make a backup network for when the wired network fails, and it can just roll right over and create an alternate connection through the cellular network as an ISP.

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LTE, HSPA, EvDO Signaling

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LTE, HSPA, EvDO Signaling

LTE Orthogonal Frequency Division Multiplexing (OFDM)

HSPA Quadrature Amplitude Modulation (QAM) and MIMO

EvDOCode Division Multiple Access / Time Division Multiplexing

MIMO

3x3 Setup9 Parallel Channels

OFDM

Pow

er

Frequency

LTEChannel

Multiple Carriers

**033 Oh, these are cool terms, right? Orthogonal frequency division multiplexing. You like that one? Orthogonal frequency division multiplexing. Or quadrature amplitude modulation, with multiple- input, multiple-output. Or code division multiple access with time division multiplexing. What is all that stuff? Here's what it is. Let me see if I've got it on the next slide. Nope. I'll talk about this just briefly, because the stuff they use in these signaling are also used in 802.11. They're also used in modems. They're also used in all kinds of technologies, because there's really

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only so many ways to do this stuff, and we keep using the same technologies over and over again. So, let's play a game. Any time you're using a radio transmission, anytime you're using RF, are you sending a digital signal, or an analog signal? Student: Analog. Student: Analog. Joe Mayes: Why does everybody say analog? Student: Because you've got to modulate it. Joe Mayes: Right, because it's a radio wave, right? And a digital signal would look like that. This you can do in Ethernet. Power on, power off, power on. When you send a radio signal, it sends with a carrier wave, and then you modulate the carrier wave. So, if I've got a carrier wave going along like this, one of the things it's supposed to do is it's supposed to be very even. And by even, that's what they mean when they say "unmodulated." "Unmodulated signal" doesn't mean a straight line; it means it doesn't change. And in this case, it's the waveform that doesn't change. Every waveform is the same as the next one. How can we change a waveform, by the way?

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Student: Increase amplitude, frequency. Joe Mayes: This is amplitude. So if I'm going to change the amplitude-- that's a change in amplitude. Right? Another way? Student: Increase frequency. Student: Frequency change. Joe Mayes: Change in frequency. Right? Do we use these transmissions every day? Student: Yes. Joe Mayes: Sure we do. Now that I've said, AM radio. What do you think is being modulated there? Student: Amplitude. Joe Mayes: Right-- amplitude modulation. And FM radio? Student: Frequency. Joe Mayes: Frequency modulation. Anything else we can do with it? We can actually do something called phase modulation, or PM. And in phase modulation, you don't send unified signals anymore. I'll give you an idea of this one. Again, this does not pass college-level RF 101 class, okay? But for a practical basis, if I've got this waveform here-- if I'm going to use frequency modulation or amplitude modulation, how many ones and zeroes can I put in this one

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wave? And that's a tough question, but the concept is one, because if this is one sine wave, and I'm doing amplitude modulation, where I'm making it bigger or smaller, then that's going to be characteristic of one letter, or one bit. If I'm going to change it by frequency, same trick, right? I've got one wave. If one frequency is a zero and the other frequency-- a longer frequency is a one, then I can only represent one character here. But let's play a game. Everybody ready for games? So, we'll start by dropping a signal line across this. So here's a question: If I only show you half the signal, can you still rebuild the entire wave for me? Student: Yes. If you flipped it. Joe Mayes: Yeah. Yeah, what you could do is essentially just flip this over and over here, right? And then you could-- if it does this, then you know it's going to do that, correct? How about if I only give you a quarter of the signal; can you still do that? Because this is the smallest unit that'll tell you both the amplitude and the frequency. You know it's the amplitude because it hit as high as it's going to go, so that's the amplitude. You know what frequency because one quarter of the wave went this tall, so the next quarter and the next quarter and the next quarter all have to have the same frequency and amplitude to rebuild the wave.

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So now that I've done that, let's have some fun with this. If that's one wave, let's divide it into its four quarters. Right? So far you all are with me? Because I'm about to make fun. So far we're still thinking like analog people in an analog world. Let's become digital people instead, and let's renumber that one, two, three, four in a digital world. We'll make this section 00, that 01, this 10, and that's 11. Everybody buy that? So now, if I were able to do phase modulation and send different phases-- if I could send this, and then send another one of those, and then send one of these, and then send one of these, have I sent-- Student: You sent an octet. Student: Zero-zero, zero-zero. Joe Mayes: But I've sent it in the space of one sine wave, correct? I still got four quarters, and I still got the amplitude and I still got the frequency. All I did was I messed with the phasing, didn't I? But now how many bits have I sent? Student: Eight. Joe Mayes: If we go back to this-- Student: Four bits. Joe Mayes: Yep. I've sent a 00 and a 00. What's this one? That's a 11. Student: One-zero.

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Student: And a 01. Joe Mayes: And this is a 01. So now I've sent eight bits in the space of what used to be one bit. Now, to be really fun, what if I also had another set of signals that were half that height? If I mess around with the amplitude as well as the phasing, then I can send three or four bits-- right? And depending how much I mess around with the phasing and how much I mess around with the amplitude, you can get all the way up to 256 bits in the space of one waveform. Anybody ever hear of QAM? Quadrature Amplitude Modulation. So you're going to mess with-- by quadrant, or by phase, you're going to mess with the amplitude. And by varying the amplitude, you're going to have a higher-- not really a compression ratio, but a higher expression ratio, or higher encoding ratio, encoding rate, that allows you to send more bits with the same waveform. That's the difference between 802.11, 802.11b, to 802.11g, to 802.11n. It's just more and more complicated encoding schemes, more and more complicated modulation schemes. And those systems get used over and over. They get used in modems. They get used in digital television and TV cable. All digital TV cable that I'm aware of in the U.S. is sent by QAM. It's all a QAM feed. Because what you're trying to do is send more bits in the same space.

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Questions? This is not a class that's going to go into any great detail about that stuff, but I will give you one last diagram. If I send this-- find a clean sheet of paper here. I talked about having this, and then having one that's also half the height, right? What if I had a whole range of these, right? So now I've got eight of them in there. If I have eight of these, times the four quadrants, what have I got? Student: Thirty-two? Joe Mayes: Thirty-two possible values, correct? How many bits does it take to represent 32? It should be five, correct? Sixteen is four; 32 is five. So I can represent five bits with every quarter wave that I send. What's the problem with this? What happens when attenuation takes a hold? Because what is attenuation? Student: Degradation of your segment. Joe Mayes: Yeah, signal loss over distance, right? Or for any other reason, signal loss. So now, what's that? Student: You don't have any separation in it. Joe Mayes: Right. I can't send a very complicated signal as far as a simple one, and still have it readable. That's the basic idea behind when you get farther away from an access point, your data rate drops on your laptop. You're sitting right next to

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the access point; you may see a connected 54 megabits. But if you only have one or two bars, you may see you're connecting at 18 megabits instead. That's the reason. The system actually negotiates back and forth and says, "What can I consistently read?" And when you're too far away for me to read a signal that's very complicated, then it's going to go to a less and less complicated modulation scheme until it reaches a modulation that it can read. Because it doesn't do any good to send at 54 megabits a second or send at 5 bits per encoding when you have to throw away three out of four of them because you can't read them. So, does that help a little bit? Yep. It's a wonderful world as we learned to send ones and zeroes over an analog waveform. And the different schemes they use are pretty fascinating. Different ways to do it are pretty fascinating. And that's how we got cellular signals to go from-- I mean, does anybody know what the original data rate was for the original cell phone texting system? It was 9600 baud, or 9.6K, right? And now we're moving megabits. It's all about how much bandwidth do you give it, and how complicated is the encoding scheme, and how smart are the receivers and transmitters. The better our chipsets get-- anybody ever hear talking about using one chipset over another for wireless? It's because different chipsets have

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different degrees of sophistication. The more sophisticated your chipset, the better it sends and receives. What's the problem with that? They want to charge more for it. That's why different devices and different laptops or a laptop and a mobile device or-- make any comparison-- not all devices are going to see the same number of bars; not all devices are going to transmit at the same rate, even when they're all talking to the same access point, because it's up to the chip system on both sides, and how discriminating they can be at reading the signal, reading the signal-to-noise ratio, anything else it takes to be able to decode the signal off the air. Questions? Student: Would they be using fast Fourier transfers to look at the signals? Joe Mayes: In some coding schemes, yes. There's actually four or five different coding schemes out there, and that's part of the game, is the difference between 802.11b and 802.11g is that they adopted a more complicated encoding scheme. And that's also why it's backward- compatible, so that when that more complicated scheme doesn't work, they can fall backward. Or, when you're talking to an older radio that doesn't support the more complicated scheme, then you can still communicate. And it allows for that incremental upgrade we were talking about that's allowed 802.11 to stay

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around so long, is because every upgrade we make is backward- compatible with the previous system. So you can buy the new laptop and it'll still operate with the old access point. Or you can buy the new access point and it'll still talk to the old laptop. Student: It's all software. Joe Mayes: Yep. Because it's all software. And that's why it's been so hard to move to 802.11a in the 5 GHz range, is because that one's not software. It takes a whole different radio operating at a different frequency. It's not just-- you don't just download a patch and suddenly you can talk about 5 GHz. It needs a 5 GHz radio.

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LTE, HSPA, EvDO Hardware

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LTE, HSPA, EvDO Hardware

Most modern mobile phones have data capabilities built-in.• Cards and dongles are available from various providers.

Since data services are closely tied to voice services, antennas and base stations are usually on cell towers.

HotHardwareForums.com

LTE Antenna

**034 So, most modern phones have data capabilities built in. And of course most modern-- there's that cellular network, right? That cellular tower. That look familiar, seeing it in the picture? Big triangle at the top because it's sectorized. Of course, the funny thing is we use cellular networks to avoid the congestion of a wireless environment, correct? But how do we connect our laptop to the cellular network that the iPad is running? We turn on tethering and talk to it over the same congested wireless network, or congested RF world, that we just tried to avoid. So every once in a

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while if you find out that you jump on the-- your 802.11 is really slow, so you say, "I'm going to jump on the cellular network instead," and you do it with tethering, and it's still slow, it's because the whole 2.4 GHz spectrum is saturated and you can't get through the saturation. Or we make it even tougher for the other people who are trying to operate in the 2.4 gig world, because your tethering is now adding to the environment. Interesting world. Lots of fun. And what you really get out of this is it's much more difficult to do this than it is to do a wired world, because in the wired world, it's all visible. You can look and see how many ports are plugged in; you can see how many switches you've got. And you get this tactile sensation that says, "I know how many wires are here." In the wireless world, we all turn it on and we expect it to work, and we don't see how many other signals are already there, unless you use some special software, special device to actually look in the environment and see it. So it's much harder for us to just walk into a room or walk into a data closet and say, "Oh, I see why your wireless is all messed up. I see why nobody can connect today. I see why everything's running so slow." In a wired world, you could do that. You could say, "Oh, look. Yeah, okay, there it is." Wireless world, we can't touch it. We can't feel it. We can't count the cables. Student: Can't tell the source.

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Joe Mayes: Yep. So, what we're going to learn later today, or in later lessons-- right? We're going to learn in later lessons-- is that you really can see that; you just got to have the right vision. Because it can be seen.

Summary

35

Summary

Standards, technology, capabilities• Wi-Fi• Bluetooth• WiMAX• LTE

**035 So, any questions? The reason we have this block is we really need just to step back, take a look at this thing, and say, "What are we doing to ourselves? What kind of a world are we walking in on?" Because the one shared media in common between all of this stuff-- Wi-Fi, Bluetooth, WiMAX, and even with tethering, even the LTE world,

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because we tend to tether into it-- what do they all share in common? The medium in the same for all of them. What's the medium. Student: Radio frequencies. Student: Radio waves. Joe Mayes: Radio waves. You can't set up two worlds of radio waves, right? Everybody operating on the same frequency is sharing with everybody else operating on that frequency. The only equivalent we get to that is if we step up to something like 5 GHz; then we're operating in a different radio world, because the 5 GHz doesn't see the 2.4. If we operate on the cellular network, which is operating at 1.8, 11.9 GHz, those don't interfere with the 2.4. So your separation is something you don't see or touch, and we tend to lose sight of how many things are operating in our environment with us. And until you kind of embed that in your own mind to say, "Every time I do a wireless installation, every time I do wireless troubleshooting, one of the things I have to remember is what's my world." Right? If I'm in the 2.4 GHz world, then I have to look at all the possible 2.4 GHz sources to understand what could be interfering. It's kind of like in-- we don't do this much anymore-- but in the wired world, if you went back to the way people were installing wire 20 years ago-- how'd people install wire? They took down a ceiling tile, they

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took a ball, they tied it to the end of the cable, or at the end of a string, the string was tied to a cable. They'd take the ball and they'd chuck it to the other end of the ceiling. They'd grab the ball at the other end, pull the string, and pull the cable straight across, right over three fluorescent lights, and they couldn't figure out why the wired network didn't work, because it was laying on top of three transformers, right? Well, we don't yet think of our wireless world in the same way. We're doing the wireless equivalent of operating right over the top of three transformers. Are we trying to operate in an 802.11 environment right next to half a dozen microwave ovens in the break room? And then we wonder why people have trouble connecting in the break room. Well, it's not because the signal's bad; it's because you've got 3000 watts of microwave oven going off 10 feet away from you. Anybody experience that at home? You may not even know it. All you know is sometimes the wireless doesn't work. And if you ever check it, you'll find out that somebody in the next room was heating up a cup of coffee, or doing something else with the microwave. And as you get more used to this environment, you become aware. You look around and you say, "Hmm, that could be a problem. Hmm, that could be a problem." And you start to think like a wireless person.

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Thinking like a wireless person makes it much easier to install and troubleshoot because you anticipate the issues and you avoid them by engineering solutions into the initial infrastructure. When I operate around a lot of RF interference, I put a lot more access points in, so they can always get a very strong signal between the end-user and the AP and not have to worry about having a very weak signal and a microwave overriding it. Because not all denials of service are attacks. But all denials of service are denials of service. When it doesn't work, at some point it doesn't matter why it doesn't work; it's just not working. And when it doesn't work, somebody's got a failure. We have to engineer around that.

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Notices

2

Notices© 2014 Carnegie Mellon University

This material is distributed by the Software Engineering Institute (SEI) only to course attendees for their own individual study.

Except for the U.S. government purposes described below, this material SHALL NOT be reproduced or used in any other manner without requesting formal permission from the Software Engineering Institute at [email protected].

This material was created in the performance of Federal Government Contract Number FA8721-05-C-0003 with Carnegie Mellon University for the operation of the Software Engineering Institute, a federally funded research and development center. The U.S. government's rights to use, modify, reproduce, release, perform, display, or disclose this material are restricted by the Rights in Technical Data-Noncommercial Items clauses (DFAR 252-227.7013 and DFAR 252-227.7013 Alternate I) contained in the above identified contract. Any reproduction of this material or portions thereof marked with this legend must also reproduce the disclaimers contained on this slide.

Although the rights granted by contract do not require course attendance to use this material for U.S. government purposes, the SEI recommends attendance to ensure proper understanding.

THE MATERIAL IS PROVIDED ON AN “AS IS” BASIS, AND CARNEGIE MELLON DISCLAIMS ANY AND ALL WARRANTIES, IMPLIED OR OTHERWISE (INCLUDING, BUT NOT LIMITED TO, WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE, RESULTS OBTAINED FROM USE OF THE MATERIAL, MERCHANTABILITY, AND/OR NON-INFRINGEMENT).

CERT ® is a registered mark owned by Carnegie Mellon University.

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