lte - the other 4g - and impact on enterprise it

LTE - the Other 4G - and its Impact on Enterprise IT | v.1 05.27.11 | ©2011 iPass Inc.

LTE - the Other 4G - and its Impact on Enterprise IT

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WHITE PAPER

LTE - the Other 4G - and its Impact on Enterprise IT | v.1 05.27.11 | ©2011 iPass Inc. 2

Table of Contents

Abstract 3

Introduction 3

The current mobile broadband scene 3

Long term evolution of universal terrestrial radio access network 4

LTE network overview 5

The reasons operators like LTE 6

The pretender to the throne – HSPA+ 7

The Future of 4G 8

So should you move to a 4G network? 8

What to consider 9

About iPass 10

References 10

Glossary 11


Abstract

WiMAX, LTE, HSPA+, DC-HSPA, 4G, 3G. If this alpha- nu-meric soup is somewhat overwhelming, then you are probably not alone. Most people who are not part of the industry find the rapidly evolving mobile broadband market quite daunting. Not only is it influencing the way people work, it is impacting the corporate IT strategies you had carefully put together 2-3 years ago. This year alone there will be over 300 new mobile broadband de-vices launched: laptop USB cards, smartphones and tab-lets. Already 100 new LTE devices have been announced for 2011. In this whitepaper we take a look at two 4G technologies that will need to be considered as you plan for the coming decade: LTE and HSPA+. Hopefully mak-ing the alpha-numeric soup more digestible.

Introduction

To paraphrase a now very famous movie… In a world far, far away, we have heard of 4G. Well now that world is far closer than you may think. For the last five or so years, industry leaders have been telling us that 4G is just around the corner. In the last few months, we have had a plethora of announcements about LTE from Me-troPCS1 , Verizon2, etc. So it now appears appropriate to take a look at the new incumbent to the 4G crown – LTE.

Much has been written about WiMAX (Worldwide Interoperability for Microwave Access) in previous literature, and it is not the intention of this whitepaper to rehash any of those discussions. The purpose here is to present LTE in a format that is easily understood and can be used to supplement the decision process on mobile broadband data options going forward. The next 12-18 months are going to be a very dynamic time in the mobile broadband arena and setting a 2 or 3 year strategy could be quite challenging.

In addition to LTE, we also discuss another alternative, HSPA+, which might be more readily and quickly avail-able in some markets. Although LTE is strong in some areas, the European market is only now starting to get into motion to auction off the desired frequencies that are optimum for LTE – with lower frequencies being better, in the case of LTE. For some, the HSPA+ route might be a very reasonable stop gap measure until LTE becomes more readily available.

This paper will discuss the move to 4G, in terms of LTE, and the implications on enterprises making mobile broadband decisions in the near term. Even with the highly touted 4G appearing in markets, there are still commercial and technical data constraints, particularly as networks are pieced together to form enterprise mobility solutions.

The current mobile broadband scene

Currently if you have a mobile broadband card or smartphone, then you are probably using a 3G or in some cases, a 2G network. Most likely this network is one of the types listed in Figure 1. In these cases the data rates available just about satisfy the application requirements on a laptop and are more than adequate for all current smartphones. The delivery of vanilla email is easily addressed by 2G technologies; it does not need to be real time.

Figure 1: Evolution of the mobile data market

If you want near real time access for web browsing or more serious streaming applications, then you have probably already moved onto the higher data rate 3G networks, in an attempt to overcome latency issues. However if you are contemplating using the enterprise

What is 4G and the Impact on Enterprise IT


cloud while on the move, then most of the current mobile broadband technologies will not easily support that aspiration. To effectively deploy a mobile enterprise cloud, higher data rates and lower delays are required, otherwise the user experience is so bad that no one re-alistically wants to use the applications. With the advent of 4G networks, and in particular LTE, the path to the fully mobile enterprise may at last become a reality.

Although most people focus on data rates as THE measure of performance, there are quite a few other data network features that need to be considered. The latency, or how long it takes to deliver the data to or from the network, is a significant consideration. If the latency is too long then packets carrying voice are de-layed, significantly impacting the quality of the service. You may have noticed this problem if you have tried to use Skype or other Voice over IP (VoIP) applications on some 3G networks. This can also translate into poor user perception of applications that require a lot of server side interaction. It is possible to produce mobile-only cloud applications but then features may have to be omitted making the experience significantly less than perfect. Tweaking the TCP/IP parameters in the laptop or smartphone has been the route taken by some companies, but this only really acts as a Band-Aid to a problem that needs a fundamental solution which is an improvement in latency.

With the introduction of WiMAX, the first to claim the 4G title, the focus changed to producing the ideal network to support the required enterprise mobility model. The user requirement drove the application rather than the network. Now with the introduction of the next 4G technology – LTE – the focus has once again shifted to the utopian view of standard cloud applications on desktop, laptop, tablets and even smartphones, provid-ing employees with a seamless view of their data and corporate services.

Long term evolution of universal terrestrial radio access network

Although the heading may seem daunting this is just the full name for LTE. As a user of mobile broadband you have been assailed with the term “4G” for at least the last 5 years. Initially all the emphasis was on the IEEE standard known as WiMAX, at least in North America. Sprint was one of the first to introduce a 4G3

claim into its promotional advertising when it decided to go with WiMAX as its broadband path.

However since that initial introduction, the spread of WiMAX has been less than stellar. Sprint had released a set of confusing claims about their 4G direction4. While WiMAX was stealing the pseudo-4G5 limelight, the 3GPP partnership (the folks responsible for GSM, CDMA and WCDMA) announced their evolutionary plans and so was born LTE. In practice, LTE turned out to be more of a revolution rather than evolution.

The LTE technology was not only driven from a technol-ogy viewpoint, but also from a reduction in operating costs to improve profitability in an increasingly competi-tive environment. Both of these factors combined to produce a network technology which is much more apt for the current mobile world than had been available in the past.

The next few sections will examine the new LTE tech-nology and explain a few things the operators may not want you to know.

To set LTE in context as of Feb 2011, there are6 :

■■ 180 operators deploying LTE

■■ 17 operators have already deployed

■■ 63 Terminal (USB dongles or Smartphones) devices to be launched in 1H11

It is hard to argue that LTE is merely paperware: the networks are real and you can now buy devices for use on those networks.


LTE network overview

LTE began with the premise that the all pervasive IP network would be the underlying transport for the new fledgling network. This immediately moved the network from the old domain of circuit switched connections in use since Alexander Graham Bell first asked Mr Watson to “come here”, to the packet domain that is now famil-iar to us from the use of VoIP networks. The cost benefit of such a move is quite significant. Voice has now simply become a very low speed packet data service. The other driving force was to flatten the network. Figure 2 pro-vides a flavor of the current, very hierarchical, GSM/3G network which is a hybrid of the circuit switched domain (Voice) and packet domain (GPRS). Even in the simplest form there are 13 different network entities. All of these physical units cost money to run, take up space and need to be maintained. Bottomline it is very expensive to run a 2G/3G network, which means that making a profit and keeping the network going becomes increas-ingly more difficult.

Figure 2: Existing 2G/3G simplified Architecture

The other cost is the number of bit/s you can put into the radio spectrum you have just bought from your lo-cal licensing body. Most people have probably read the stories about operators paying significant amounts of money to license the precious spectrum. Without spec-trum, you do not have a network!

Generally, the licensing terms provide for a fixed period of use in a defined frequency range. Clearly to get the biggest benefit, an operator will want to put as many bits/s as possible into their newly purchased bandwidth. You may already have heard the term spectral efficiency. Although it sounds a very complex term, all it really

means is how many bits/s can I squeeze into my fre-quency range. In the days of 1G or 2G networks, things were not very spectrally efficient. This meant I would be paying quite a sizeable amount of money to provide bit/s to my user, so the Bits/s/$ would be high. Moving through the 3G and then to 4G, the efficiency improved by several orders of magnitude. With the move to 4G, the bits/s/$ has come down significantly.

In order to really improve those operating expenses, the network architecture in Figure 3 evolved. As you can see from this network, we now only need three entities to achieve our network goals. Not only have we reduced our operating expenses by about one-third, but we have also improved the network performance – in very simple terms, fewer nodes need to touch the data so we have a faster response time or lower latency. The control for the network is all via IP systems rather than traditional database models. Keep in mind that this is a greatly simplified view of the network, however it is a fair comparison to existing 2G/3G networks.

Figure 3: New simplified LTE network

In order to keep the hardware costs low, it was decided to use a radio technology that was already well under-stood from its use in military radio and more recently in 802.11a WLAN - Orthogonal Frequency Division Mul-tiplexing (OFDM). OFDM is very simple to implement in terms of software or hardware. This means that the cost of the radio station can be very low. Indeed many of the new generation of radio stations can be defined by the software they have loaded. It is therefore very


easy to change the radio technology being used on the system. This is unlike the ‘old days’ when a new radio would require a total hardware replacement, some-times euphemistically referred to as a “fork lift up-grade.” The basic OFDM system can also be enhanced by the use of multiple antennas, sometimes referred to as MIMO (multiple-ins, multiple-outs), power con-trol and forward error correction coding. With all these enhancements, OFDM turns out to be very spectrally efficient based on the current level of technology avail-able.

One of the other benefits of OFDM is that it is quite easy to pick how much bandwidth you want to use. So with LTE OFDM it is possible to use anywhere from 1.5MHz up to 20MHz of bandwidth in easy increments. What does this mean? Well it means an operator can initially roll out LTE using spare bandwidth. When users are mi-grated across to the new system, an operator can start to take over more spectrum from the previous genera-tions of network, slowly removing bandwidth from a 2G or 3G service. This is sometimes referred to as “spec-trum refarming.” In this case with, for example, 900MHz spectrum, it would be possible to slowly replace the 2G technology currently residing there with new LTE technology. Since the radio in the new LTE hardware is software defined, it is simply a matter of upgrading the software when the time comes to change the band-width. In some cases this may not even be required. One other additional benefit of such an approach is that an operator can take advantage of new enhancements in the standard without having to upgrade hardware. So the lifetime of the new hardware is greatly enhanced.

Thus far in this discussion there has been no mention of THE killer network application – voice, although voice may soon be linked with video. The voice application does exist in LTE and goes by the not very exciting acro-nym of VoLTE – Voice over LTE. Because the LTE net-work is highly optimized, delivering voice is not a major problem although sometimes it does seem to have been an afterthought. In this case, however it is well worth waiting for because it will pave the way for HD voice quality. More simply, it will be possible to put behind us the highly questionable voice quality introduced by the compressed speech that was inherited from the old fixed telephony network. Most networks that are deploying will see VoLTE added by the end of 2011 or

even earlier in some cases. Once this is added to the network, the reason for the existence of 2G and even 3G networks becomes questionable.

These are just a few of the enhancements that will be available with LTE. There are already features that are now in the planning stage that will further enhance the LTE experience; watch out for LTE Advanced. The other great benefit is that some of the world’s largest equipment vendors are 100% behind the standard, and with over 200+ networks committing to deploy LTE, the cost savings due to the volume of network and terminal equipment brings its own benefits.

The reasons operators like LTE

Even from this very brief introduction to LTE, it is quite clear that the LTE network is a significant departure from the previous networks deployed by most opera-tors. The biggest change has been the flattening of the network architecture. It has very few nodes and relies heavily on IP for most of the protocol/control which means that operators can take advantage of the huge pool of Internet engineers out there. The other aspect often neglected in most discussions of the LTE network is that it allows operators to consider the possibility of switching off their 2G and 3G networks in the not-too-distant future. Most operators feel that their 2G net-works will be gone within a few years, and the spectrum they occupied taken over by LTE. The 3G networks will probably follow suit within a few more years. So by 2015 most of the 2G and 3G networks could be gone and the spectrum reused.

With the flat network and upgraded equipment, the operational expenses (OPEX) drop dramatically as can be seen from Figure 4. The addition of a very efficient radio interface both spectrally and in terms of band-width use means that operators are free to choose how to roll out the network, either slowly in some areas or rapidly in others where they can offer better broadband experiences, while still maintaining the legacy 2G and 3G networks. The cost per bit/s is much lower with LTE than with the incumbents which means the operator can drop the cost to remain competitive if needed or increase profits if they are so inclined. Most operators are claiming that the ROI for their new LTE network is under 12 months and in some markets under 6 months. As the new networks stabilize and the operators take


on the task of driving their new networks it is not un-reasonable to expect that not only will the data rates improve but those rates will be maintained under load.

Whether the data plans return to the days of fixed all-you-can-eat pricing or whether the tiered approach will still be used, it is hard to say. However, the competition in the LTE space will be fierce in the coming years, so expect network pricing to vary significantly as operators vie to retain their customer base. If all goes well with the new LTE networks starting in 2012, or sooner in some cases, the drive will be on to begin the move from 2G/3G to LTE with operators offering incentives to move to the new networks and thereby free up the 2G/3G networks for removal in the later part of the decade. In countries with tight spectrum controls, this move may be much quicker or as the license for the 2G/3G spec-trum expires in some cases.

Figure 4: OPEX for 2G, 3G and LTE networks

The pretender to the throne – HSPA+

Although it may appear that LTE is the only 4G option for providing mobile broadband solutions to all, there is another technology that some operators are promot-ing as their 4G offering. Called HSPA+, also known as Evolved High-Speed Packet Access, this technology is a derivative of the existing 3G WCDMA networks. It uses the same schemes as 3G and improves the data rates to about 84Mbps using higher modulations (more bits in the same bandwidth) and some of the same antenna techniques used by LTE. With even more added features, it will be possible to push the data rate even higher; up to 600+Mbps if all the features are implemented.

The issue with HSPA+ is that it suffers from the same issues that plague the current 3G networks. The cover-age and performance are not consistent. At the cell edges the data rates, even with HSPA+, may be no better than are available with current 3G technologies. However closer to the cell tower, the data rates can be quite high, but on average a user may not notice a sig-nificant improvement in their data rates. This problem is not present in the LTE solution as the data rate is mostly consistent over the whole cell coverage.

Another option for improving performance, again based on the existing 3G technology, is to aggregate more channels or carrier frequencies together. This approach is known as Multi Channel-HSPA (MC-HSPA) or in its current form Dual Channel-HSPA (DC-HSPA). The im-provement in bandwidth is achieved by adding a second channel into the original data connection when the ap-plication demands more data. Initially the application on the laptop may only require the bandwidth provided by one channel. However, if needed it is possible to add in another channel to boost the performance even further. This approach benefits from using existing technology and simply adding in the ability to dynamically allocate a second channel. Since there is no increase in the bits used in the bandwidth, the solution does not suffer from the same cell range issues as HSPA+. The additional channel allocation also means that it is possible to gain from transmit diversity in that the data takes two inde-pendent routes to the mobile broadband cards. Since the second channel is only allocated when needed, it means that it can be used by other users when idle. Hence the network is more efficient. It is always a good idea to fully utilize the spectrum allocated to your net-work.

The HSPA+ and DC-HSPA routes are, at best, a stopgap measure and, at worst, a diversion by the operators who have taken this path. It can also be argued as to whether or not these enhancements to existing tech-nology are in the spirit of the 4G network drive. In their defense, some operators have been forced down this path by lack of available spectrum for new network in-troduction. If the spectrum to deploy LTE is not available it might be almost impossible to begin the move from 3G to LTE. A number of operators who have quickly deployed HSPA+ or DC-HSPA7 have also announced their intention to deploy LTE as soon as the spectrum is available.


As of Feb 2011 there were 76 live HSPA+ networks regionally broken down as:

■■ North America 8

■■ Middle East and Asia 12

■■ N Europe 20

■■ W Europe 21

■■ Asia-Pac 15

■■ 6 networks support 28Mb/s and higher

The Future of 4G

In this whitepaper we have reviewed the new additions to the 4G family. As both LTE and HSPA+ are relatively new incumbents to the 4G arena, they already have quite an extensive evolutionary path ahead of them. As can be seen from Figure 5, the plan is to head towards much higher data rates on HSPA+ and LTE by 2015. So there is a very extensive five year window for LTE and probably a three year window for HSPA+.

HSPA Evolution

LTE

721

2842

84168 336...

0

42

84 126 168

World record: 168 MPS

150 bps50 bps1000 bps

150 million peoplecovered daily

Figure 5: Evolutionary paths for HSPA and LTE (Source: Ericsson MWC, Feb 2011)

From Figure 6, it is clear there will be at least a 5x projected growth in mobile broadband subscriptions by 2016. Although HSPA is shown as the bigger slice of the pie, this may change slightly depending on the success of LTE. Some operators are already seeking to supplement or replace their HSPA network with LTE so as with all future predictions; who really knows? The use of 3G technologies may be limited to certain areas in the world, however with the scarcity of spectrum (it is a finite resource), 3G may well disappear quite quickly. Furthermore it should be noted that some of these sub-scriptions will be for Machine 2 Machine (M2M) interactions and that growth could be phenomenal in the next 5-10 years.

Indeed just in 2011, there are predicted to be over 400 million smartphones on the existing 3G and 4G net-works generating data traffic that would be equivalent to 4 billion 2G GSM users! All this data leads to the conclusion that the current 4G networks (WiMAX, LTE and HSPA+) may not be able to satisfy the insatiable appetite that is being generated for data services. The use of cloud services will certainly drive the data use for most enterprises. If smartphones and laptops can be configured to support telepresence, that may drive usage even further. It was not that long ago (1994) that it was very hard to find a good use for mobile data!

MBB Subscriptions Technology Share 2016

5000

4000

3000

2000

1000

0 2010 2016

Mobile PC & Tablets

Handhelddevices

HSPA TD-SCDMA CDMA2000

EV-DO Mobile WiMax

85% of subscriptions on HSPA and LTE in 2016

Figure 6: Projected growth of Mobile Broadband users by 2016 (Source: Erics-son MWC, Feb 2011)

So should you move to a 4G network?

As with most things - it depends. Certainly if your con-tract is due to expire and your operator offers incentives to move to 4G, then you should seriously consider that move. The 2G network is very likely to disappear soon, squeezing users on those networks into a deteriorating service spiral. Of course operators want to move you off that network. Similarly as the 3G network bandwidth is reduced, to be used by the 4G network, performance will most likely degrade. The early adopters of 4G net-works are likely to see similar changes in the network not only in improving data rates but also expanding coverage – more positive network aspects.


So if you are considering a change then keep in mind the following points:

■■ Does the 4G network have coverage in the areas I will be working? Coverage will roll out more slowly in some areas. However most operators are using lower frequencies for their LTE networks so the cov-erage might actually be better than the 3G coverage.

■■ Are there devices that will support my working methods? Do you need a laptop, tablet or smart-phone to perform essential tasks, and will employ-ees have a mix of devices?

■■ Can I roam internationally with my chosen network (if required)? If this is an important requirement then LTE and HSPA are the only ways to go to pro-vide a reasonable chance of roaming.

■■ Are there any incentives to move? Data cards change on an almost 6-monthly basis so the card you have now is probably already obsolete. If it is an old 3G card then it might be best to move. Or if you use an embedded card in your laptop per-haps it’s time to upgrade that laptop. In terms of smartphones, the picture is even more bleak. They become obsolete even more quickly.

■■ Are there methods to control my data costs? Current plans are tiered but this may swing back to the all-you-can-eat model when competition begins to bite. However managing these costs is an impor-tant consideration. Using LTE with a 5GB cap could mean you use that limit within 32 minutes down-loading a file or streaming some video formats.

What to consider

Looking at 4G in your enterprise mobility strategy, con-sider these tips:

■■ Pick the carrier whose coverage matches up best today and in the coming year with where your mo-bile employees will need the service.

■■ Feel free to mix and match carriers and also consid-er Wi-Fi as an option until 4G becomes ubiquitous in the US. The connection for Wi-Fi is predictable and the cost model is well known and fairly transparent. Some operators bundle a WiFi service into their offering making this option seamless to the user.

■■ Go ahead and commit to a 2-year deal, knowing that you will likely have true competition between carriers in 2013 and that you will, in all likelihood, benefit from the fact that you will continue to have some leverage.

■■ There will still be handoff issues between networks. As a user is handed off from an older network to a newer one, it might not be a smooth transition. The coverage of LTE will be much better than 3G. In practice most LTE operators will not provide a handover option to 3G, there will be no need.

■■ Carefully consider 3-year commits with a carrier, as 2013 could be an inflexion point as it relates to service pricing, performance, availability and device support.

■■ The Clearwire network architecture will support a move to LTE. Clearwire states an 80% overlap and announced their move to LTE in May 2011. Every Sprint handset/data card built in 2011 will have LTE capability.

■■ If Sprint 4G provides the required footprint then they may be a good interim solution until 2012-13.


References

1. MetroPCS’ New 4G LTE Plans Offer Unprecedented Value and Choice With Prices Starting at Just $40 (1/3/11)http://investor.metropcs.com/phoenix.zhtml?c=177745&p=irol-newsArticle&ID=1511941&highlight=

2. Verizon Wireless Brings 4G LTE To More Than 145 Markets By The End Of 2011 (3/22/11) http://news.vzw.com/news/2011/03/pr2011-03-21a.html

3. Sprint 4G Expansion Plans to Stretch Coast-to-Coast from Los Angeles to Miami (3/23/10) http://newsroom.sprint.com/article_display.cfm?article_id=1410

4. Sprint CEO Says WiMAX Bet Paid Less Than Hoped (12/7/10) http://www.pcworld.com/article/212878/sprint_ceo_says_wimax_bet_paid_less_than_hoped.html video at: http://kara.allthingsd.com/20101227/d-dive-into-mobile-the-full-interview-video-of-sprint-nextels-dan-hesse/

5. Will Sprint Dump WiMax For LTE? (3/7/11) http://www.informationweek.com/news/mobility/wifiwimax/showArticle.jhtml?articleID=229300496

6. Sprint Could Be Ditching WiMax For LTE (2/10/11) http://www.businessinsider.com/sprint-well-tell-you-more-about-our-4g-plans-later-this-year-2011-2

7. Sprint talks seriously about LTE, suggests it could complement WiMAX (2/17/11) http://www.engadget.com/2011/02/17/sprint-talks-seriously-about-lte-suggests-it-could-complement-w/

8. Sprint’s CEO Says Clearwire in ‘Every Option’ for Future (3/9/11) http://www.businessweek.com/news/2011-03-09/sprint-s-ceo-says-clearwire-in-every-option-for-future.html

About iPass

Founded in 1996 iPass (NASDAQ:IPAS) is a leading provider of enterprise mobility services with over 3,500 customers, including more than 370 of the Forbes Global 2000. The company’s mission is to be the voice of the enterprise in the market for mobility services by provid-ing solutions that simply, smartly and openly facilitate

access from any device on any network, while providing the visibility and control necessary to contain spiraling mobility costs, maximize mobile user productivity and maintain security in a world where consumers drive enterprise IT.

For more information, visit www.iPass.com or follow iPass on Twitter at www.twitter.com/iPass

Bearer Technology Peak Rate Available (Kbps) Potential Rates (Kbps) Year

GSM CSD (2G) 9.6 9.6 1991

HSCSD 115 115 ~1999

CDMA2000 1xRTT 153 153 1999

GPRS (2.5G) 115 115 ~2000

UMTS/3G 384 384 2002

1xEV-DO Rev.A 3,072 3,100 2007

HSDPA/HSUPA (3.5G) 2,000-5,760 1,200-14,400 2009

HSPA+ (~3.99G) 21,600 17,600-42,000 2009

WiMAX (~3.99G) 2,700 10,000 2008

3xEV-DO Rev.B 4,900-14,900 14,900 2010

DC-HSPA+ 23,400-42,200 23,400-84,000 2010

LTE (~3.99G) 12,000 100,000 2010

LTE-Advanced (4G) X 100MBps-1GBps >2012

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and product names may be trademarks of their respective companies. While every effort is made to ensure the information given is accurate, iPass does not accept liability for any

errors or mistakes which may arise. Specifications and other information in this document may be subject to change without notice.

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Glossary

2G: Second Generation Wireless. A digital cellular in-cluding GSM systems, CDMA, TDMA.

3G: Third Generation Wireless. A generation of stan-dards for mobile phones and mobile telecommunication services fulfilling the International Mobile Telecommu-nications-2000 (IMT 2000) specifications; also com-monly described as graceful enhancements to the GSM cellular standards.

3GPP: Third Generation Partnership Project (3GPP) was formed in 1998 to foster deployment of 3G networks that descended from GSM, as well as those standards that evolved from cdmaOne (IS-95).

4G: Fourth Generation Wireless. The latest wireless wide area network (WWAN) technology. Designed to in-crease data transfer speeds for Web surfing and video, the ITU has designated LTE, LTE-Advanced, WiMAX 2 and HSPA+ as 4G technologies. For example, as of 2011, Verizon uses LTE; Sprint uses WiMAX; T-Mobile uses HSPA+, and AT&T uses LTE and HSPA+.

CDMA: Code Division Multiple Access. A method for transmitting multiple digital signals simultaneously over the same carrier frequency (the same channel). The most widely known application is for cellphones.

GPRS: General Packet Radio Service. The first data service for GSM cellular carriers. GPRS added a packet capability to GSM.

GSM: Global System for Mobile Communications. A digital cellular phone technology based on TDMA that started in Europe and migrated to other continents. In the US, it uses a different frequency.

HSPA: High Speed Packet Access. A family of high-speed 3G digital data services available to GSM carriers worldwide. The service works with HSPA cellphones as well as laptops and portable devices with HSPA modems. Although based on WCDMA, HSPA is a major enhancement with more channels and different modu-lation and coding techniques.

HSPA+: Evolved High-Speed Packet Access. A wire-less broadband standard defined in 3GPP release 7 and above. HSPA+ provides HSPA data rates up to 84 Megabits per second (Mbit/s) on the downlink and 22 Mbit/s on the uplink through the use of a multiple-antenna technique known as MIMO (for “multiple-input and multiple-output”) and higher order modulation (64QAM).

LTE: Long Term Evolution. The next-generation 4G technology for both GSM and CDMA cellular carriers. Approved in 2008 with download speeds up to 173 Mbps, LTE was defined by the 3G Partnership Project in the 3GPP Release 8 specification. LTE uses a different radio interface and packet network architecture than previous 3G systems.

WCDMA: Wideband Code Division Multiple Access. This is another name for UMTS (Universal Mobile Telecom-munications System), a cellular network also referred to as 3GPP. As the name suggests, WCDMA is based on CDMA technology and was envisioned for the next generation of GSM. It’s a European standard designed to support data transmission rates of 144kbps for use in vehicles, 384kbps for pedestrian use and up to 2mbps for use indoors.

WiMAX: Worldwide Interoperability for Microwave Access. Also known as the IEEE 802.16 group of stan-dards, which defines a packet-based wireless technol-ogy that provides high-throughput broadband connec-tions over long distances. This was originally intended for point-to-point microwave links, but later extended to support mobile applications.