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Chipmakers are eyeing 700MHz prize

Posted: 01 Oct 2007 ?? ?Print Version ?Bookmark and Share

Keywords:WiMAX? 700MHz spectrum? chipmaker? wireless technology?

Chip designers for cellular and WiMAX networks are sharpening their pencils on plans for 700MHz support in the wake of new guidance from the U.S. Federal Communications Commission (FCC) on the spectrum. A race is on to determine who will have what chips with what performance dynamics ready when new spectrum owners start planting towers as early as February 2009.

Qualcomm is working to characterize its current and future CDMA technologies for 700MHz with initial chips shipping next year. WiMAX players are readying both products and standards for the 700MHz opportunity. Proponents of the Long-Term Evolution (LTE) version of cellular are still completing their specs, and work is under way on products for High Speed Packet Access Plus (HSPA+).

"This is a very, very exciting time in wireless, with a lot of interesting high-performance technologies coming out that should deliver horsepower that customers will really feel in the form of new applications," said Bill Krenik, manager of advanced wireless architectures for Texas Instruments Inc.

Much of the excitement stems from the FCC's decision to make 700MHz, like the Internet, available to any device or application, something today's cellular carriers do not allow.

'No lock, no block'
"That this spectrum could get deployed with no lock and no block is something that just doesn't exist in the U.S. today," said Sriram Viswanathan, an Intel Capital VP who runs Intel's WiMAX program and lobbied for the ruling.

In the end, carriers that win the spectrum will choose a technology based on the lowest dollar per bit per hertz, the Intel exec said. WiMAX supports channels as wide as 20MHz, compared with 11MHz for Ultra Mobile Broadband (UMB). And UMB and LTE are based on intellectual property closely held by a few companies such as Ericsson, Nokia and Qualcomm. "WiMAX is built on a fairly broadly held patent portfolio," Viswanathan said.

"I think the incumbent operators, should they get the spectrum, will deploy UMTS, CDMA and their respective broadband upgrade paths of LTE and UMB," said Craig Mathias, principal of wireless consulting firm Farpoint Group. "But I'd like to see a single, all-IP network deployed, which means WiMAX or even something else could be the wireless technology of choice going forward."

WiMAX does not have a defined profile for 700MHz yet, but Intel and others said one is in the works.

"All the current WiMAX chip providers will be in the 700MHz market, and those who don't have the luxury of their own RF transceivers will join with companies that do have the RF, like Freescale, TI and Maxim," said Will Strauss, principal of market watcher Forward Concepts.

"Many chip companies, including Fujitsu, are reviewing their internal development programs to determine how to best align their chip strategies and implementation plans with this expanded spectrum opportunity," said George Wu, director of the wireless group at Fujitsu Microelectronics, a WiMAX chip vendor. "We have received wish-list comments from some of our customers about the 700MHz band and are reviewing their requests while keeping a close watch on the open-access policy development."

The FCC will auction off a total of 694-806MHz previously used for analog TV. The prime real estate includes two sections in the upper C block set aside for open, commercial broadband wireless services.

TI earlier announced it is supplying WiMAX chips to Motorola, which will supply systems for a WiMAX network that Sprint will deploy in early 2008. Krenik would not reveal details of those chips or say whether TI has plans to support 700MHz for any of the other technologies.

HSPA+ contender
Krenik did note that HSPA+, based on release 7 of the 3GPP standard, will be a contender for 700MHz networks because it can deliver throughput of up to 25Mbps on a 5MHz channel. LTE is also a contender and delivers up to 10Mbps to the terminal, although that requires a 20MHz channel. But the LTE standard is still not completed.

"Deploying LTE in early 2009 when the 700MHz spectrum is available would be very aggressive," said Krenik, noting that Japan's DoCoMo has a test LTE network running in its lab today.

"One thing I lose sleep over is whether the technology road maps will slip, and I will have to deploy an interim solution before one of these 4G technologies is ready," said Stagg Newman, chief technology officer for Frontline Wireless, a startup that hopes to buy some of the new spectrum rights.

Cellular chip and system makers will have to clear plenty of hurdles to have products ready for deployment in 2009. They will be applying orthogonal frequency-division multiple-access technology more broadly than ever before, as well as using broader swaths of spectrum (up to 11MHz) to carry signals. They must do this in a relatively constrained 700MHz, where some transmit and receive channels will be separated by as little as 12MHz.

'More complex bands'
"This is one of the more complex bands," said Peter Carson, senior product manager of next-generation cellular chips at Qualcomm CDMA technologies. The 700MHz band will carry two-way broadband networks for commercial and public safety applications, and high-powered DTV broadcast for services such as Qualcomm's Media-FLO mobile TV network. The FCC is still refining the rules on how all those services will work.

"We did a first round of analysis of the Qualcomm chip designs based on a lot of assumptions about the regulations," said Carson. "Now, we are doing a second round of analysis based on the ruling that came out Friday. We expect to be able to be more specific in a month or two."

Who will play in the new 700MHz bands? A comparison of emerging wideband mobile technologies.

'Recons' expected
More rulings may be yet to come. Companies such as Frontline expect to file petitions for reconsiderationcalled reconsasking for changes in the most recent rulings, Newman pointed out. "Usually, there are no major changes with the recons," said Newman, a former chief technology officer at the FCC.

Qualcomm plans to ship a quadband chipset supporting 700MHz for its existing Ev-DO Rev A and B technology in time to enable systems launches for expected deployments starting in 2007. A similar chipset for its next-generation Rev C technology, also called UMB, should be ready by June 2009 at the latest. The Rev A technology promises peak PHY layer data rates of 3.1Mbps down to a terminal and 1.8Mbps up from a terminal. Rev B can support three such channels, and Rev C boosts theoretical peak bandwidth to 40-80Mbps.

According to Carson, cellular technologies such as UMB have an advantage over WiMAX because they use frequency-division multiplexing rather than time-division multiplexing. Time division duplexing (TDD) can cause throughput to fall off dramatically at the edge of a cell site, he said.

Krenik said carriers can adjust TDD networks to optimize them for actual traffic patterns, mitigating the problem. Viswanathan said both the IEEE and the WiMAX Forum are developing FDD standards for WiMAX, though they will not be completed until late next year.

For its part, Intel is sampling prototypes of its Echo Peak chipset, which supports both 802.11n and WiMAX. It will be part of the company's Montevina notebook platform, shipping in late 2008.

- Rick Merritt
EE Times

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