A cluster of vendors led by Cisco Systems Inc. and BroadcomCorp. took the wraps off a wireless technology last week that they hope will put MCIWorldCom Inc. and Sprint Communications Co. on course to challenge cable in thebroadband-services arena.
If the new wireless-broadband system -- targeted formultichannel-multipoint-distribution-service spectrum and other microwave tiers -- worksas planned, it will allow MCI, Sprint and other players in fixed-wireless services todeliver a full slate of video, voice and high-speed data to homes and small businesseswithout stinting on coverage or service variety.
"The most encouraging part of this development is thatit really validates our choice of wireless as a medium for delivering broadband servicesto the mass market," Sprint spokesman Russ Robinson said.
Underlying the new wireless-broadband platform is atechnology known as "vector orthoganal frequency-division multiplexing,"developed over the past four years by Clarity Wireless Inc., which Cisco acquired one yearago.
Cisco is making the technology available free-of-charge toBroadcom and other chip-makers in an effort to establish it as a de facto industrystandard that maximizes the broadband-service potential of microwave-based deliverysystems, director of marketing for broadband fixed wireless Steve Smith said.
"Our game is to get fixed wireless moving as a viablecompetitor to cable and DSL [digital subscriber line]," Smith said. "We'vechosen this technology as the one to back because it delivers both a higher spectralefficiency and a higher link efficiency than anything we've seen."
Broadcom -- which is supplying chips for the currentwireless-broadband market, founded in QAM (quadrature amplitude modulation) and QPSK(quadrature phase shift key) technologies -- is swinging behind VOFDM for the same reason,vice president of marketing Tim Lindenfelser said. "This technology overcomes thesevere line-of-sight and other limitations of other approaches to MMDS," he added.
While MCI and Sprint plan to launch next-generationwireless-broadband systems as soon as the first quarter of 2000, Broadcom will be in aposition to supply VOFDM chips to systems and customer-premises-equipment makers earlyenough next year to meet deployment schedules for most carriers' wireless-broadbanddeployments, Lindenfelser said.
Robinson said that while the new system offered"exciting" possibilities, Sprint has issued a request for proposals for initialmarket build-outs, and it would be unfair to vendors responding to that RFP to give anunqualified thumbs-up to a new system that has yet to be fully tested.
"We've looked at [VOFDM], and we are lookingforward to what these guys come up with," he added.
Together, MCI and Sprint have secured control of MMDS in120 markets representing 60 percent of U.S. households, with 80 markets now falling underSprint's umbrella, Robinson said. By the end of the second quarter, Sprint plans tohave 10 cities operational on the new wireless-broadband platform, which starts withhigh-speed two-way data and one-way cable and later adds voice services, he added.
"We'll be operational in 30 markets by the end of2000," he said. The first 10 include Phoenix, San Francisco and Detroit -- wherecompanies acquired by Sprint were already operating -- as well as seven other markets tobe named later.
The new "BCM2200" ASIC (application-specificintegrated circuit) -- which combines VOFDM technology and media-access control in asingle chip -- will be priced low enough to allow manufacturers to deliver customerequipment at costs nearly on par with cable gear, Lindenfelser said.
"The main difference [in cost] is the antenna,although there's some trade-off there with the cost of the tuner that's requiredin cable," he noted.
Lindenfelser declined to set a delivery date for commercialproduct, but he said samples of the new ASIC would be available to manufacturers in thefirst half of 2000.
One reason why Broadcom can proceed so fast and so cheaplyis because it is tapping the same MAC technology used in DOCSIS (Data Over Cable ServiceInterface Specification) chips, officials said. They also noted that the VOFDM technologyhas gone through several development phases over the past four years, giving the partnersconfidence that any further design refinements before volume production would berelatively minor.
VOFDM involves two basic techniques that backers said willallow network operators to achieve high levels of market coverage with enough bandwidthper user to support everything from voice to high-definition TV. This is a tall order,given the fact that operators only have approximately 200 megahertz of spectrum to workwith.
The vector part of the nomenclature refers to the fact thatthe system uses spatial diversity. That means it uses a dual-feed antenna receiver at theend-user premises to capture signals coming in from separate paths and combines them tomaximize the signal-to-noise ratio at any given frequency.
This helps to strengthen the signals bouncing offreflective surfaces, reaching users that are not in direct line of sight of thetransmitter, Lindenfelser noted.
Spectral efficiency -- which maximizes the number of bitsper hertz, or cycle of frequency -- is achieved through the orthoganal frequency-divisionmultiplexing aspect of the technology, where the number of bits inserted into thin slicesof frequency, or "frequency bins," depends on the noise-tolerance level withineach frequency segment.
"We pack a lot of carriers into the spectrum andweight them based on signal-to-noise [ratio], which gets away from the modulation-capacitylimitations you encounter when you use a single carrier over a 6-MHz channel," Smithsaid.
The result is a system that delivers 20 megabits per secondin a 6-MHz channel to all users, wherever they happen to be, Broadcom product-line managerPete LaRocca said.
Moreover, the chip, operating at baseband, can apply themodulation technique to a signal that's destined to go out at virtually anyfrequency, whether it's at the 1.9-gigahertz level of PCS (personal-communicationsservices) or at the 28-GHz level of LMDS (local multipoint distribution service).
But it's MMDS -- and specifically the high-volumedemand anticipated from a combined MCI and Sprint -- that comprises the immediate targetsfor the development activities of the new alliance.
"We think this technology is what Sprint and WorldComneed to be successful as providers of broadband services over fixed-wireless local-accessnetworks," Smith said.
Other players signing on with the initiative includeMotorola Inc., Texas Instruments Inc., Samsung Telecommunications America Inc., ToshibaAmerica Consumer Products, Pace Micro Technology plc, Bechtel Telecommunications, LCCInternational, Electronic Data Systems Corp. and KPMG International.
So far, the only player involved that will be supplyingheadend equipment is Cisco, but Smith said it appeared that other systems suppliers wouldsoon join, since Broadcom and TI will be making their chips available to Cisco'scompetitors.
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