Fixed media

Broadband fixed wireless technology always has been a subject that has done little more than smolder at Wireless 2000's overwhelmingly mobile annual show. This year, though, many environmental factors combined to turn the broadband wireless heat a little higher.

In the local multipoint distribution service (LMDS) category, contributing factors include increased pressure coming from LMDS spectrum license holders for deliverable equipment from the highly touted point-to-multipoint category. By the accounts of many service providers, first generation point-to-multipoint vendors have yet to deliver the performance metrics the technology format has promised, and second generation gear still is not quite ready for prime time. That leaves many commercial and pre-commercial service providers in a tight spot - particularly in the eyes of their boards and shareholders.

At the same time, many service providers report that prices of more traditional point-to-point gear are dropping to the level that deployment for LMDS applications is becoming more cost-effective. That has breathed new life into a technology format considered proven, yet prohibitive, and put even more pressure on point-to-multipoint proponents to make good on their promises.

Finally, the multichannel multipoint distribution service (MMDS) spectrum has experienced a revival during the past year, driven in large part by interest and acquisitions by Sprint and MCI WorldCom. As those carrier behemoths prepare to award equipment contracts for their newly minted MMDS licenses, suppliers of equipment for the spectrum range were on hand at Wireless 2000 to tout their solutions.

To the multipoint

It appears that major vendors of point-to-multipoint LMDS gear are taking their potential customers' equipment readiness and adaptability concerns seriously. At the Wireless 2000 show, Nortel Networks took evolutionary steps with the announcement that its Reunion line of point-to-multipoint equipment now supports ATM-based TDMA formats in addition to frequency division multiple access (FDMA). The vendor is trying to steer clear of the air interface argument by providing gear that can answer all preferences.

"We're now in a position to say, `pick it - we don't really care,'" said John Skoro, marketing director for Nortel's broadband wireless access unit. The TDMA format is more applicable for small-businesses and single-tenant buildings, while FDMA is optimized for multitenant dwellings and large business customers seeking dedicated bandwidth, Skoro said.

Newbridge Networks is another multitechnology vendor that used Wireless 2000 to showcase its broadband wireless equipment. The company claims deployments in the networks of 60 carriers worldwide in different frequencies.

Newbridge, which is in the process of being acquired by Alcatel, is challenged with trying to maintain that kind of success curve in the face of ownership and management changes and increasing competition from upstart broadband wireless access vendors pursuing new architectures. The company's ability to match its data networking core with multiple access technology formats is one way to combat that competition, said Tony Jenkins, assistant vice president of product management for Newbridge's broadband wireless access group.

"Smaller players are always a threat, especially the smart guys who are focused on a single concept," Jenkins said. "As a multiservice player, the plan for us is any form of access."

To keep up with demand, Newbridge has contracted with four radio equipment developers, which Jenkins said helps the company price its systems more competitively.

"It drives the cost down. If you do it all in-house, it can't get to the cost point of a standardized solution," he said.

TDMA and FDMA are not the only technology differences sparking debate in the broadband wireless world. In the transmit and receive channels of the access link, much debate has occurred over whether time division duplexing (TDD) or frequency division duplexing (FDD) is the superior format. FDD systems use separate channels for transmit and receive, while TDD allows dynamic allocation of upstream and downstream bandwidth within the same channel.

Wavtrace, one of the industry's TDD supporters, announced that it has received a patent and has been awarded FCC authorization for its LMDS and 38 GHz systems. Wavtrace attributes the relatively slow uptake of point-to-multipoint systems to cautiousness on the part of spectrum holders and competitive pricing of alternative technologies. The company currently has trials under way in the U.S. and several other countries and recently released its second generation system, a phase it expects will jump-start skittish carriers to deploy.

"Part of it is that the local exchange carriers have excess capacity and are pricing it below cost to keep the CLECs from buying their own equipment," said Thomas van Overbeek, president and CEO of Wavtrace. "And people are just nervous or cautious. Everyone knows that the second generation is coming."

The other tiers

Although point-to-multipoint is certainly the most intriguing technology sector of late within broadband wireless, other areas have begun to generate higher interest. For example, several vendors of point-to-point gear were at Wireless 2000 to tout how their solutions can be used in increasingly flexible ways - even as part of LMDS networks.

Giganet, for example, develops high-capacity point-to-point systems for multiple millimeter wave spectrum ranges used in several countries, including 38, 26, 18 and 23 GHz. The company plans to ship a 28 GHz LMDS product by the end of the first quarter, and the system is not likely to be used only for backhaul, said Shraga Katz, president and CEO of Giganet.

His opinion is that about 25% of a broadband wireless network will be composed of point-to-multipoint equipment, with the balance being made of point-to-point equipment. In other words, the formats are complementary.

"We are cooperating in tenders with point-to-multipoint vendors, so I don't feel like I'm in competition with them," he said. "Our focus is in high-capacity."

The lower-spectrum multichannel multipoint distribution service (MMDS) area was another active broadband wireless technology niche at Wireless 2000. BreezeCom, a developer of wireless LAN gear, announced that it has adapted its systems to operate in the 2.5 GHz MMDS spectrum and is close to being able to ship data-optimized systems with the additional capability of carrying voice over IP. The company's TDD approach is ideal for MMDS applications because spectrum license holders have different numbers of channels in different markets, said Bernard Herscovich, president of BreezeCom.

"It's very attractive because the number of channels each operator has is not the same and the position is not the same, so the solution has to have a lot of flexibility," he said.

Herscovich predicted that carriers using MMDS spectrum will be able to provide small business and residential customers with bandwidth similar to that provided by cable modems and DSL. Although the system is designed for data services, the voice-over-IP support will expand the capability of the system, he said.

"Voice is just another application that can be supported on top of Internet access," Herscovich said.

Airspan Networks, a company spun out of DSC Communications when DSC merged with Alcatel last year, also has designed a system design that can be applied in the MMDS spectrum. The company has versions of its product that can be used in the 1.9 GHz PCS spectrum, the MMDS spectrum and the 3.5 to 3.7 GHz spectrum used primarily in Europe, said Chris Rogers, regional vice president for North America at Airspan.

At the Wireless 2000 show, Airspan announced that it has signed an OEM agreement with Motorola under which Motorola will market and distribute Airspan's AS4000 and AS8100 products, which both operate in the 3.5 GHz spectrum.

ADC is another vendor active in the MMDS realm. Shortly after Wireless 2000, the company introduced its new Axity system, the next generation of the company's CellSpan product line for MMDS. The system, which is based on the DOCSIS+ standard, supports carrier-class data and voice service over the 2.1 GHz MMDS spectrum and has the ability to tailor bandwidth allocation in the upstream path, said Frank Kelly, director of marketing operations for ADC's broadband access and transport group.

"It's very flexible in terms of offering graduated data rates to different customers," Kelly said. "It's really the operator's choice."

Several different broadband wireless formats were clearly creating some smoke of their own at Wireless 2000, despite the mobile-centric history and focus of the show. With the kind of momentum these technologies are building - and the activity expected from service providers over the coming year - next year's show is likely to be even hotter for broadband wireless.