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WiMAX trails in 4G race

Posted: 24 Jan 2007 ?? ?Print Version ?Bookmark and Share

Keywords:4G? WiMAX? wireless technology? CDMA? WCA?

WiMAX won't grab the brass ring as the technology that defines 4G cellular systems. But it is likely to capture a healthy minority stake in that emerging sector, and it could help bring Internet access to a new generation of consumer devices.

That was the assessment that emerged from the annual gathering here of the Wireless Communications Association International (WCA), a lobbying group whose members generally promote WiMAX. While proponents, including Intel Corp., have fueled plenty of hype about the broadband wireless technology, last week's confab made it clear that WiMAX holds real, though limited, promise and faces several challenges.

Even WiMAX proponents in the WCA admitted that Long Term Evolution (LTE), a follow-on to cellular's GSM standard, will command the lion's share of fourth-generation cellular systems. That's because the huge breadth of GSM service providers will be able to roll their subscribers over from today's wideband CDMA to LTE when the time comes. LTE is still being defined.

There are a whopping 122 commercial wideband-CDMA networkswith 70 million subscribersoperating in 55 countries and using 407 distinct handsets today, reported Jake MacLeod, chief technology officer of Bechtel Communications Inc. "There's a huge momentum for existing wireless services," said MacLeod, whose company builds public networks for carriers.

By contrast, no carriers have deployed the 802.16e mobile WiMAX spec officially defined at last year's WCA meeting. That's because carriers decided they wanted to deploy a 2G version of the spec supporting the same multiple-input, multiple-output (MIMO) antenna technology that will be used in LTE and in rival technology under development at Qualcomm Inc.

Systems for that version of WiMAX won't be certified and available until late this year. In addition, the technology faces nagging spectrum debates that impede some uses. "We're moving the flag down the field, but not as far as we thought," said MacLeod.

MacLeod said carriers Sprint Nextel, startup Clearwire and Russia's Sistema have committed to WiMAX, while Cingular and Vodafone are backing LTE. AT&T, BT and Verizon may use WiMAX as an adjunct to their fiber-to-the-home deployments, and satellite broadcasters are considering WiMAX as a back channel, he added.

Long term, "LTE will garner the market share advantage [in 4G cellular], but WiMAX could grab a very significant portion of itperhaps as much as 20 percent. That's a gargantuan market globally," said MacLeod, whose company has hundreds of active network deployments worldwide, including some of the largest cellular systems.

Given the delays, Sprint Nextel has scaled back 2007 spending plans on WiMAX from $1 billion to "up to $800 million," said Philip Solis, a senior mobile analyst at ABI Research. "Systems and service providers wanted to make sure they got .16e right before it went out the door, and the result has been something of a mess."

In a sign of the continuing development work, Navini Networks announced it has ported its MIMO and beam-forming technology from CDMA-based systems to its mobile WiMAX gear. The company uses a group of eight antennas in a 2-by-4MIMO arrangement along with proprietary algorithms running on Texas Instruments DSPs to achieve an extra 9- to 18dB for its link budget, said Yasser Hannush, product-marketing manager for Navini.

The good news for WiMAX backers is that interoperability testing is moving forward and new chipsets are on the horizon. Chad Pralle, vice president of marketing for SR Telecom, a WiMAX system maker, said his company expects to see versions of Intel's Rosedale-2 chipset as early as February that implement both .16d and .16e. "People want to see a d-to-e upgrade where you just push a button and don't require any new hardware. Last year, there were no chip sets for this upgrade," said Pralle.

Separately, Intel reaffirmed its plans to field combined Wi-Fi/WiMAX modules and low-power X86 CPUs starting in 2008 that will power a new generation of ultramobile consumer devices linked to the Web. Intel will show devices as early as April that will halve power consumption compared with today's handhelds, the company said.

Intel expects to follow up next year with devices offering a tenfold reduction in power draw. The 2008 devices will also include very low-power X86 CPUs now in design under Gadi Singer, who worked on both the Itanium server and the Xscale cellular processors at Intel.

"These [end systems] will not be phones or PCs," said Anand Chandrasekher, the general manager of Intel's ultramobility group. "We believe that with a 4-inch display, you can see a full Internet screen that is very readable. To unleash this, you need broadband wireless, and we believe that is WiMAX."

Carriers like Sprint are said to be attracted to WiMAX primarily as a replacement for the leased lines they use to backhaul cellular traffic. But Atish Gude, senior vice president of Sprint's mobile broadband group, said one of the features that makes WiMAX stand out is its ability to break old cellular business models by supporting new users and new devices, bought at retail.

"We will build a model conducive to owning multiple Internet devices," said Gude. "Getting to an open Internet model is something we have to strive for, because it's an Internet model that will make this profitable for the industry."

Spectrum remains a factor limiting some WiMAX uses. One carrier at last week's meeting lamented that his company could deploy WiMAX in the United States today to serve rural users if the government would approve WiMAX at 3.5GHz. Many countries outside the United States allow WiMAX at 3.5GHz.

Other conference goers said the United States should open up use of WiMAX at 700MHz, where new spectrum will be available after the government reclaims analog broadcast TV airwaves in February 2009. Still others advocated for use of WiMAX at a variety of frequencies where it is still not approved.

- Richard Goering
EE Times

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