Network Solutions - This Year's Models

Posted 02/2001

Network Solutions

This Year's Models
2nd-Gen Broadband Fixed Wireless Offerings Multiply
By Paula Bernier

With limited carrier deployments of early broadband fixed wireless equipment already in place, a crowd of vendors has begun hawking what is generically described as "second-generation" equipment--promising better spectral efficiency, and, in some cases, non-line of sight transmission, among other new benefits.

Sprint Corp. (www.sprint.com), with significant MMDS spectrum rights in its back pocket, is the coveted customer for most of these suppliers. Sprint and WorldCom Inc. (www.wcom.com) are the big license holders of MMDS, having invested a combined $2 billion after the FCC (www.fcc.gov) opened the spectrum for two-way use in 1996. But, in addition to well-known companies like Sprint and WorldCom, and XO Communications Inc. (www.xo.com)--the largest holder of LMDS spectrum rights--lesser-known names such as Fuzion Wireless Communications Inc. (www.gofuzion.com)and Nucentrix Broadband Networks Inc. (www.nucentrix.com) also provide vendor opportunity.

Still, because of the large number of equipment companies in this nascent market, the pool of competitors is expected to thin. "There are so many little vendors playing in this space now because Sprint and WorldCom bought up all these licenses," says Michael Greeson, consulting analyst at Parks Associates (www.parksassociates.com). "I don't think we're going to be at all surprised when we see a large amount of consolidation."

But hopes are high for broadband fixed wireless, which many pundits say is positioned not just to fill in where DSL and cable modem fear to tread--as some had initially posited--but in fact to go head-to-head with these more-established access mediums.

"Using MMDS and LMDS to reach underserved areas was [initially] the mantra of everyone--Sprint, WorldCom, etc. But I thought that was rather coy. Now Sprint has gone to major metro areas--Tucson, Phoenix--and slapped up radio towers," says Greeson.

David Sumi, director of strategic marketing at vendor Malibu Networks (www.malibunetworks.com), adds that although broadband fixed wireless has a late start compared to cable modems and DSL, "cable modems have a long way to go before becoming ubiquitous, and DSL will never be ubiquitous."

Chart: Total U.S. Broadband Wireless Subscriber Revenue

Noting that a wireless broadband hub can be deployed within a week and service can be turned up within a matter of hours, IGI Consulting Inc. (www.igigroup.com/consulting.html) goes as far as to say broadband fixed wireless access is "the single most important access technology in the telecommunications industry." Broadband fixed wireless is also attractive in that service providers need only invest in network infrastructure after customers sign on. The firm forecasts that broadband wireless revenues will exceed $17 billion by 2005, up from $800 million in 2000.

So, naturally, vendors are working to bring to market new and improved equipment that they hope providers will use to capitalize on that opportunity.

Non-Line of Sight Near?

Tony Carmona, an analyst at IGI, says that next-generation broadband fixed wireless equipment offering non-line of sight capabilities of less than a mile (between the base station and end user) is expected to hit the market in a big way this year.

Modulation schemes such as orthogonal frequency division multiplexing (OFDM) will aid in non-line of sight and will also help carriers get to higher speeds--up to 27mbps for MMDS and up to 54mbps over unlicensed spectrum, Carmona says, adding that the first-generation MMDS promised 27mbps but didn't get up to that rate in actuality. "But speed is secondary to line of sight," he adds.

Vendors pushing non-line of sight systems include Cisco Systems Inc. (www.cisco.com), Malibu, NextNet Wireless Inc. (www.nextnetwireless.com), Raze Technologies Inc. (www.razetechnologies.com), and SPEEDCOM Wireless Corp. (www.speedcomwireless.com), where vice president of marketing and product management Patrick Pacifico says the company's future products will be based on OFDM.

NextNet lays claim to having the industry's first non-line of sight system for MMDS. Called Expediance, the system is designed for service providers targeting residential and SOHO users. The company, as of late last year, had completed alpha testing on the product, was planning betas for January and expected to make the product available in volume in the third quarter of 2001.

"Unlike other products, we are available today and we are absolutely non-line of sight," says NextNet marketing manager Barb Heine. "We're going through metal and brick buildings."

But other vendors say non-line of sight is a misnomer.

Wi-LAN Inc. (www.wi-lan.com)vice president of product management Scott Campbell explains that his company employs wideband OFDM (W-OFDM) because it's resistant to multipath (or interference from various devices operating in or around the same frequency) so "that gets us something called 'near-line of sight.' No radio product is non-line of sight, what they are is near-line of sight." W-OFDM is a modulation scheme that offers improved bandwidth and noise tolerance. Wi-LAN's I.Will 300-24 product, which supports W-OFDM, was in trials late last year with undisclosed users.

Troy Trenchard, director of product marketing at Cisco, believes that, despite the commonly used phrase, there is no such thing as non-line of sight. "Nobody can send a signal through a mountain. Whenever anybody says non-line of sight there's a layer below that" relating to power level, frequency shifting if there is reflection, what kind of service is being transmitted at what rate, and many other factors, he says. "We have the first shipping OFDM system that can handle obstruction which is near non-line of sight. We can go through foliage; we can reflect signals to get around obstructions."

Cisco, whose products are based on its popular UBR7200 series routers, has been shipping since last March a point-to-point product used in limited backhaul deployments. The company in December began shipping an MMDS point-to-multipoint system, which Nucentrix is testing in Amarillo, Texas. Both products employ vector OFDM, Cisco's own brand of OFDM that is backed by the IEEE group the Broadband Wireless Internet Forum (www.bwif.org), which also includes component vendors Broadcom Corp. (www.broadcom.com), Texas Instruments (www.ti.com) and Toshiba America Inc. (www.toshiba.com), among others.

Meanwhile, Iospan Wireless Inc. (www.iospanwireless.com), formerly known as Gigabit Wireless, says its AirBurst System will be the first end- to-end wireless solution to incorporate smart-antenna, multiple-input, multiple-output (MIMO) technology and provide the advantage of non-line of sight, fixed wireless broadband operations. That product, scheduled to launch this year, is based on the company's MIMO-OFDM technology, which Iospan says forms the basis for next-generation fixed broadband standards being defined by the Wireless DSL Consortium (WDSL, www.wdslconsortium.com). The WDSL Consortium also includes ADC Telecommunications Inc. (www.adc.com), Conexant Systems Inc. (www.conexant.com), Intel Corp. (www.intel.com), Nortel Networks Corp. (www.nortelnetworks.com) and Vyyo Inc. (www.vyyo.com).

Chart: Subscriber Revenue by Technology

For its part, Malibu expects to make available for beta tests a non-line of sight product based on OFDM and operating in unlicensed spectrum. General availability of its first products is scheduled for July.

Sumi of Malibu says OFDM schemes' practice of sending out multiple waves enables them to support non-line of sight.

"You take the payload or packet and divide it up into smaller packets so reflection is less of an issue," he says.

Other vendors planning to offer products based on various flavors of OFDM include Cisco Systems and Wi-LAN.

Sumi adds that Malibu's products will also support dynamic modulation, meaning the system can change modulation as needed. "The RF [radio frequency] environment changes because trees grow and buildings get built and you don't want to have to change" the system every time there's such an alteration, he explains. The product's dynamic FEC (forward error correction), meanwhile, will ensure that a signal gets to its destination in the event of a barrier, such as a tree blowing in the way of the signal, says Sumi. But the system only does this type of FEC oversampling when the environment requires it, he says, so no bandwidth is wasted.

But not everybody targeting non-or near-line of sight is embracing OFDM.

Raze Technologies' founder, CTO and senior vice president of engineering, Paul Struhsaker, says his company supports non-line of sight by doing adaptive modulation, adaptive FEC and advanced signal processing including equalization.

"We have chosen not to use OFDM because it increases the cost of the analog section of modem," Struhsaker says. "There are other just as robust modulation schemes that don't require that added cost. Single carrier block frequency adaptive modulation is what we use. It's like OFDM, but does it at the receiver only. Ours is a little more computationally intensive, but chips are cheap."

John Frederick, vice president of ADC's Broadband Wireless Access Division, adds that OFDM, which ADC has elected not to support, is a simple modulation technique and in and of itself does not achieve non-line of sight.

Maximizing Spectrum Use

Many next-generation broadband fixed wireless systems also promise better spectral efficiency.

"In my mind, what's interesting is that there are products out on the market today, but they're not enough," says Randall Schwartz, marketing manager at BeamReach Networks Inc. (www.beamreachnetworks.com), formerly Radix Technologies. "There's not enough capability for an operator--whether an ILEC or CLEC--who wants to go into a market and become a major broadband provider, be competitive against cable modems and DSL and capture 10 percent to 25 percent of the market. The current products can't do that without putting down a base station once every couple of miles," which isn't cost efficient. So there's a need for new spectral efficiency, he says.

According to Schwartz, Sprint went with its current system primarily because that's what was available at the time. He says Sprint representatives made some comments at the recent National Wireless Engineering Conference and OFDM Forum events indicating the company is looking for solutions with higher spectral efficiency. Schwartz says Sprint can only support about 10,000 users in any one market with current technology.

Schwartz says BeamReach has developed an advanced version of OFDM that incorporates adaptive beam forming, multifrequency transmission, time division duplexing (TDD), spatial processing and other technologies. That "brew of technologies" allows carriers using its systems, which primarily target the MMDS band, to realize spectral efficiency (bits per hertz) that is 10 times that of today's broadband fixed wireless systems.

"That enables you to reuse frequencies within a cell because you can form a beam going to the left and going to the right on the same frequency, and they won't interfere with each other," says Schwartz. "It greatly reduces the overall interference because you don't have to broadcast information that creates multipaths, and [it includes an] antennae array" rather than a single omni- directional antenna.

ADC's Frederick says his company's Axity product, which he identifies as a second-generation system that's been on the market in volume since the middle of last year, offers better coverage because it's a multicell solution (which can also support supercell). In fact, he says, ADC participated in one of the first multicell trials in the world, with WorldCom in Boston. According to Frederick, multicell offers this better coverage because it's near-line of sight; and because it has multiple cells, the system can see more cells or businesses. It also employs frequency reuse for more capacity, he adds.

Meanwhile, Wi-LAN (whose systems operate at 2.4 GHz and 900 MHz, unlicensed spectrum in the United States, and 3.6 to 3.9 GHz in the United Kindom) has a technology called HopperPlus, which is spread spectrum. But instead of frequency hopping, it uses one frequency right after the other, resulting in high data throughput, says Campbell. The company expects to come out with its third-generation products in volume midyear.

Adding Voice

While high-speed data is the focus of broadband fixed wireless vendors, some are now beginning to support voice services with their products.

In fact, Raze Technologies chairman, president and CEO John J. Festa feels its voice features are a clear differentiator of the company's products, which target the residential and SOHO space.

"We're solving the problem of bundling voice and high-speed data," he says, explaining that, when claiming the system supports voice, he means two to four lines of lifeline voice with all the CLASS features, while at the same time supporting data at rates comparable to or exceeding DSL.

The company expects to announce beta test customers for the system in the second quarter. And Festa says Raze's strategy is to go after several regional CLECs in Texas.

ADC's product also "has a clear path to voice," says Frederick. "We're using DOCSIS [the CableLabs standard] plus MAC [media access control], so it's standards-based. By using DOCSIS it creates path to voice and a path to QoS."

Sumi says that Malibu has also designed the MAC layer protocol in its products to support QoS, allowing the network to assign a jitter and latency budget on a per-transaction and per-flow basis to support different kinds of traffic like voice or data. It can also take into consideration the SLAs of the subscriber, he says. And it has a predictive scheduler that reserves a bandwidth slot for each transaction for which a user has subscribed, he adds.

Who's on First?
By Paula Bernier

Despite all the excitement surrounding Sprint Corp.'s (www.sprint.com) broadband fixed wireless activities, the carrier recently announced plans to scale back its initial rollout for MMDS.

The initial plan was to be operational in 20 markets by the end of 2000 and a total of 20 to 30 markets by the end of 2001. Late in 2000, the company changed its plans to include 13 markets by the end of 2000 and a total of 14 markets by the end of 2001, says Russ Robinson, spokesman for Sprint's national consumer organization. That's a result of cost-cutting efforts at Sprint due to "fallout of the failed merger" with WorldCom (www.wcom.com), says Robinson, and a desire to wait for second-generation equipment.

"We have a couple of vendors in the lab looking at non-line of sight," he says. "We're also very interested in a cellular concept called cellularization and segmentation to reuse frequency within cells. We're already doing that in some markets."

In its current broadband fixed wireless deployments, which are point-to-multipoint networks offering high-speed data at 256kbps upstream and 500kbps or 1.5mbps downstream, Sprint is using modems from Hybrid Networks Inc. (www.hybrid.com) and radio equipment from California Amplifier Inc. (www.calamp.com) and Thomcast Communications Inc. (www.comarkcom.com).

Rumors are rife that Sprint is unhappy with its current equipment and is ready to drop Hybrid as a supplier, but Robinson wouldn't confirm that and noted that Sprint holds a financial stake in Hybrid.

Also, Sprint continues to install Hybrid equipment. Indeed, on Dec. 5 the vendor issued a press release noting that Sprint is using an undisclosed number of Hybrid's two-way system for new deployments in Salt Lake City and Wichita, Kan.

According to Michael Greeson, consulting analyst at Parks Associates (www.parksassociates.com), in mid-September Sprint bought an additional 16,000 routers for two-way MMDS from Hybrid.

But Eric Stonestrom, CEO and president of Airspan Networks Inc. (www.airspan.com), which started as a division of DSC Communications Corp. (www.dsccc.com) and is now owned by Alcatel (www.alcatel.com), says there are rumors that Sprint will issue a request for proposals soon.

"Hybrid is a cable modem with a strong radio, so it can't tolerate any co-channels or adjacent channels. That's why we use W-CDMA [wideband code-division multiple access] to manage interference to allow us to scale," says Stonestrom, whose company recently introduced an MMDS product.

The vendor says it doesn't have any relationship with Sprint or WorldCom relating to MMDS. But the company is working with a Nebraska-based carrier called Long Lines Ltd. (www.longlines.com), which is 35 percent owned by WorldCom, on a broadband PCS product. "Our strategy is ... WorldCom is monitoring that PCS activity and WorldCom may consider our MMDS product," he says.

According to Greeson, WorldCom has MMDS spectrum rights to operate in 160 markets, representing 50 million households--half the households in the U.S. Trials are under way in Baton Rouge, La.; Boston; Dallas; Jackson, Miss.; and Memphis, Tenn., he says, but WorldCom has not announced a timeline for commercial deployment.

The third hot prospect for MMDS vendors is Nucentrix Broadband Networks Inc. (www.nucentrix.com). The company has filed for authority to operate in 70 markets in Texas and the Midwest and is the biggest MMDS license holder after Sprint and WorldCom. The company to date is using equipment from Cisco Systems Inc. (www.cisco.com).

In addition to MMDS, other service providers are using LMDS--most notably Teligent Inc. (www.teligent.com) and Winstar Communications Inc. (www.winstar.com)--PCS and unlicensed frequencies to offer broadband fixed wireless services.

AT&T Corp. (www.att.com) for some time has been dabbling in the PCS spectrum with a broadband fixed wireless system called Project Angel, first in Chicago and now in Dallas.

IGI Consulting Inc. (www.igigroup.com/consulting/html) has estimated that there are approximately 150 wireless ISPs in the United States offering wireless Internet access in the unlicensed bands. And IGI expects that, as more equipment becomes available and is more affordable, the number of wireless ISPs will grow dramatically, to more than 1,000 by 2005.

But, Greeson says, the FCC (www.fcc.gov) has been very disappointed with the lack of interest in unlicensed spectrum available for broadband fixed wireless, which is commonly known as the unlicensed national information infrastructure (UNII).

"They thought it would be a hotbed of activity by entrepreneurs, but that's not happened at all," says Greeson. "There's been very little activity in the 5.15 through 5.25 GHz and 5.725 to 5.825 GHz areas." Greeson doesn't expect any significant activity in the UNII band to develop because there's a lack of interest by the larger players.

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