Generated by Jive SBS on 2009-12-07-07:001

Service Provider Mobility: LTE vs. WiMAX:Part 1: Introduction

Posted by Rajesh Pazhyannur Oct 15, 2009

Duel to the Death or Different Strokes for Different Purposes?

Google the phrase "LTE vs. WiMAX," and the results might lead you to thinkthere's a battle royal going on out there – say, like the one over what to do withthe U.S.'s crazy quilt of medical insurance. Here's a sampling:

· T he 4G Wireless War

· LTE vs WiMAX: A Little 4G Sibling Rivalry

· Why LTE Vs. WiMAX Isn't Your Typical Standards Battle

· LTE vs WiMAX: SPRINT CTO attacks LTE, but admits WiMAX harder

· This WiMAX vs LTE battle…like the US Democratic Presidential race

· LTE vs. WiMAX: The Battle Is in the Market, Not the Lab ...

· Face-off: LTE vs. WiMAX

And that's just from the first 10 hits.

The truth is, 4G wireless technology evolution isn't a "Betamax vs VHS" winner-take-all competition. In fact, it's not, properly speaking, a competition at all. It's

Service Provider Mobility: LTE vs. WiMAX: Part 1: Introduction

Generated by Jive SBS on 2009-12-07-07:002

an engineering question. And like all engineering questions, choosing technologydepends on not just on technical factors. A simplistic answer is that  WiMAX isfrom Mars – data  – and LTE is from Venus – voice.

And just as both Mars and Venus have their essential place in the scheme ofthings, so LTE and  WiMAX, too, have their respective places in meeting businessgoals – from profitability and customer retention, to business expansion andchanging market demands.

So let's turn down the volume and look at LTE and WiMAX in terms of architecture(mobility, security, access-gateway) and physical layers (transmission modes,duplexing types) comparatively –instead of competitively – and map these tooperators' business and strategic concerns.

The first part describes LTE and WiMAX evolution and history. The second offers a system-level LTE and WIMAX comparison, focusing on system architecture and protocol stacks forthe control and user traffic. The third part describes the air interface for LTE and WiMAX.And part four ties it all together.

How we got here: LTE and WiMAX pedigrees

One of the tried and true rules of conflict resolution is that all parties get toexplain where they're coming from. Likewise with LTE and  WiMAX – we needto understand where the players are coming from. So let's take a walk downtelecommunications memory lane and see how this happened.

Back when Southwest décor was hot and Don Johnson ruled prime time, wireless' firstgeneration (1G) was born with the first commercial cellular networks, which were basedon analog standards. These were quickly followed by a second generation (2G) of digitalcellular standards using digital modulation and signal processing.

Service Provider Mobility: LTE vs. WiMAX: Part 1: Introduction

Generated by Jive SBS on 2009-12-07-07:003

As the World Wide Web began spawning information overload, this second generation ofcellular telephony spawned competing digital voice standards. North American operatorsadopted IS-95, which used Code Division Multiple Access (CDMA). In other parts of theworld, many operators deployed Global System for Mobile communication (GSM), whichused Time Division Multiple Access (TDMA). LTE has roots in both of these standards.

As we all acquired mobile phones, carriers needed more efficient voice transport.And, people started thinking about doing things with cellular networks thathad nothing to do with voice – GSM, for example, was capable of also carryingdata (at speeds as high as 14.4 Kbps!). The International TelecommunicationsUnion (ITU) unveiled a third generation (3G) standard – IMT-2000 – for supportingapplications beyond voice, enabling growth, and increasing bandwidth.

This gave birth to two distinct 3G standards groups to advance 3G networkdeployment: 3rd Generation Partnership Project (3GPP) and Third GenerationPartnership Project 2 (3GPP2), for GSM  and CDMA respectively. An alphabetsoup of standards for next-generation data communications on cellular networksfollowed in the wake of these groups: EV-DO, EDGE, HSDPA, HSUPA – you getthe idea. However, when the dust settled, the 3GPP and 3GPP2 camps madecommon cause behind a 3GPP technology called LTE (Long Term Evolution).

Meanwhile, back at the IP ranch, the IEEE was engaged in a similar, paralleland completely independent effort. As many of us added the phrase "Internetdisconnection anxiety" to the language, an IEEE working group drew theblueprint for keeping us perpetually connected by extending wireless broadbandaccess from LANs to Metropolitan Area Networks (MANs) and Wide Area Networks(WANs). The working group leveraged the DOCSIS – Data Over Cable ServiceInterface Specification – standard heavily, especially in the definition of theMAC  layers (so, they were not reinventing everything, only the physical layer).In 2004, this new standard made its debut as IEEE 802.16; introducing a newtransmission scheme, OFDMA (orthogonal frequency division multiple access). Itsnickname was WiMAX (Worldwide Interoperability for Microwave Access)

Service Provider Mobility: LTE vs. WiMAX: Part 1: Introduction

Generated by Jive SBS on 2009-12-07-07:004

The difference between the WiMAX-Mars family tree and the LTE-Venusfamily tree can be illustrated by the following story. In the mid-1990s a friendtelephoned me from India using his company's new Voice over IP technology. Orat least, the telephone rang and I detected Ron's voice at the other end of it. Tohim this call represented a technical triumph because it proved that  the Internetcould carry voice communications – otherwise known as phone calls. To me itrepresented an unacceptably bad phone call.

Now, without folks like Ron figuring out how to turn a phone call into a data file, I wouldn'thave the slick unified communications system that transcribes my voicemail and sends it tome on email, or lets me seamlessly return an email with a phone call that also shows thesubject of the email I'm responding to. But without folks who understand my non-negotiableexpectation of a dial tone when I click "call," Internet telephony would remain an historicalfootnote, like the Radio Trading Company's 1932 electro-mechanical See-All Radio-VisionReceiver.

Which brings us back to the present Mars-and-Venus squabble between WiMAX and LTEproponents. Next up: LTE and WiMAX: an apples-to-apples comparison.

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