The Future of 4G: LTE vs. WiMAX
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LTE, the 4G mobile broadband technology backed by major cellular network equipment providers and operators, casts a long shadow across the WiMAX landscapeeven though LTE products are thin on the ground and no operator has launched commercial service using it.
Verizon, however, has committed to rolling out LTE (Long Term Evolution) starting next year, delivering ten times the data throughput of current 3G technologies. Others, including NTT DoCoMo in Japan, France Telecom, Vodafone in the UK, AT&T, and T-Mobile, have also said they will adopt LTE rather than WiMAX.
Meanwhile, Sprint, Clearwire, and Comcast in the U.S., UQ Communications in Japan, and Yota in Russia are all aggressively rolling out mobile-capable 4G networks using the current version of WiMAX, 802.16e (2 to 10 Mbps), in urban markets where they will inevitably compete with 3G (and later, LTE) providers.
The WiMAX Forum claims that 504 operators in 145 countries have deployed WiMAX, but many use older 802.16d technology that cannot provide mobile services, and many are small operators in developing countries or rural regions.
How will the market unfold? Are LTE and WiMAX on a collision course? If so, which will prevail. Or will the two technologies co-exist, even complement each other? The answers are far from clear, and depend to a large extent on who you ask.
One thing most observers agree on: there isnt much to choose between the technologies. Both grew out of the GSM air interface and use IP networking, an OFDM (orthogonal frequency-division multiplexing) RF modulation scheme and MIMO (multiple-input, multiple-output) smart antenna technology.
Its hardly surprising they use many of the same building blocks, said Ciricia Proulx, senior product marketing manager for WiMAX at semiconductor giant Intel Corp., a major investor in WiMAX and WiMAX projects (Clearwire, UQ). There are only so many ways to deliver multi-megabit mobile throughput with seamless handoffs. Proulx estimated that WiMAX and LTE are 80% to 85% the same.
Godfrey Chua, research manager in the wireless and mobile infrastructure group at IDC, agreed there are more similarities than differences, but pointed out that LTE was designed with mobility in mind from the get-go, while 802.16 evolved from standards based on fixed wireless networking. He conceded this mainly manifests in ways that users would rarely notice, but may still give LTE a slight technological advantage.
The technological differences between the two are a moving target, however.
The ITU, the International Telecommunications Union, is developing specifications for 4G mobile. Neither WiMAX, 802.16e, nor the current LTE standard, revision 8, meet basic preliminary objectives for 4G, said Phillip Redman, a vice president of research at consulting and analyst firm Gartner Inc.
Sprint and Clearwires use of the term 4G to describe their 802.16e technology does not reflect adherence to international standards, Redman pointed out. It refers to the fact that this is the fourth generation of mobile wireless technology deployed in North America.
How and when either camp will deliver a standard that does meet the yet-to-be-finalized ITU specs remains to be seen. It is anticipated that LTE will get there with revision 10 and WiMAX with a projected 802.16m. Estimates of when equipment based on these advanced standards will appear ranges from 2011 to 2015.
Despite the similarities of the two technologies, and despite suggestions from some that the two camps are not necessarily on a collision course, discourse between and around them can get heated.
In this corner
Redman wrote in a report last year, "WiMAX drives the hype for 4G, but LTE will be the dominant standard," A WiMAX skeptic and a perceived thorn in the industrys side, he believes LTEs dominance is not a question of technological superiority or even cost, but of market politics.
Politics rules everything, he said, explaining the reasons so many major mobile operators chose LTE rather than WiMAX as their upgrade path to 4G.
Those operatorsVerizon, AT&T, NTT, et aldidnt really choose the technology, Redman believes. They chose their suppliers: Ericsson and Nokia, tried-and-true Tier 1 mobile infrastructure equipment manufacturers that had decided not to back WiMAX.
If operators wanted to go with WiMAX, they had to bet on smaller Tier 2 suppliers, such as Motorola, Alcatel-Lucent, and Alvarion. Its all about who you feel most comfortable with, Redman said. Better the devil you know?
The Tier 1 suppliers, in turn, backed LTE over WiMAX because they saw that, for a variety of reasons, they could make more profit selling LTE. In many cases, it was more a political decision than one based on technology or cost, he said.
Redman has reportedly gone as far as urging businesses to hold off on investing in WiMAX, at least until the equipment ecosystem evolves to make dual-mode 3G-WiMAX devices more readily available.
This enraged some elements in the WiMAX camp. One Intel blogger characterized Gartners analysis of the market as the most recent attempt at drive-by kneecapping of the technology.
When we repeated to Proulx Redmans suggestion that WiMAX vs. LTE might be analogous in some ways to the showdown between VHS and Betamax video cassette formats in the 1970swith WiMAX taking the doomed Betamax roleher response was blunt.
Its a silly analogy and its unfortunate its been repeated so often, she said. Proulx noted that Betamax was a proprietary technology, backed by one supplier (Sony) and was more expensive than its competitornone of which is remotely true of WiMAX.
Proulx was similarly direct in responding to Redmans suggestion that 802.16m is a more uncertain proposition than LTE Rev 10 and may not even be backward compatible to 802.16e. From day one, she said, the first [design] requirement [for 802.16m] was that it be fully backward compatible. I think youll see evidence of that very soon.
Chua apparently does not raise the ire of the WiMAX community to the same extent as Redman, but his perspective is not so different.
IDC believes operators rarely have made or will make either/or choices between LTE and WiMAX. More often, decisions will be made for them because only one technology or the other can meet all their needsgiven time-to-market, desired business model, and other considerations.
We characterize WiMAX and LTE as two circles that overlap, Chua said. Inevitably there will be some competition, but competition is not the overriding market scenario. Its not what defines those two markets.
Going to market
That said, he too believes WiMAX will have a tough time overcoming market factors arrayed against it. He argues that LTE will be building from a customer base of 4.6 billion mobile users worldwide, while WiMAX mainly has appeal as a replacement for DSL, especially in developing markets where wireline broadband technologies are not available. It will be building from a much smaller base: fewer than a billion customers worldwide.
IDC will publish a forecast later this year showing sales of LTE equipment surpassing WiMAX equipment sales some time in 2012.
But it may not be as simple as 3G mobile users in developed markets sticking with their current providers and waiting for LTE, while WiMAX is relegated to a niche role delivering portable rather than mobile service in developing countries and rural regions.
For one thing, the WiMAX camp believes the momentum its currently building in those developing markets will drive development of an ecosystem, help harden the technologyand put it in good position to be a full competitor in the 4G mobile market down the road.
Indeed, the fact that WiMAX lets operators in those markets start small and build businesses organically without investing billions of dollars is one of its key advantages over LTE, Proulx said. Operators may start by providing DSL replacement services, but can easily evolve to offering true mobile services when they have the breadth of coverage and market demand.
And then there are the implications of exceptional initiatives in more developed marketsClearwire in the U.S., Yota in Russian, UQ in Japan. Yota is currently signing up 2,000 new subscribers a month in St. Petersburg and Moscow and already has 200,000 since launching last fall, Proulx said.
While Clearwire has been slow to introduce WiMAX-powered phones or dual-mode 3G-WiMAX phones that would help it attract customers away from 3G providers, Yota is already building much of its marketing around a dual-mode device from HTC.
Most observers agree that the winners in the 4G market will be those that offer the widest coverage, the most reliable service and the best choice of devices. Redman is skeptical Clearwire can build its network out quickly enough to give it the breadth of coverage needed to attract 3G customers. The company will need another big infusion of capital next year just to continue its current pace, he added.
But Proulx believes WiMAX can compete with 3G operators, if not immediately in the U.S. then soonand perhaps sooner in Japan. There, she said, UQ expects to have 90% of the Japanese population covered by its network by the end of 2010. If true, that would be before NTT is even out of the gate with LTE.
Redman and Chua may be underestimating the market strength of WiMAXor not. Either way, no one is seriously suggesting it will be blown out of the water by LTE. The two will co-exist, whether or not peacefully remains to be seen.
Indeed, the picture is unclear and may be no clearer until 2011 when commercial services using both will be available in the U.S. and elsewhere. Stay tuned.
Gerry Blackwell is a veteran technology journalist and frequent contributor to Wi-Fi Planet. Read more of his ongoing WiMAX coverage here.