Capitalizing on the wide availability of spectrum in the 94-GHz realm, the WCA's Engineering Task Force for Spectrum Policy Above 40 GHz hopes to make several gigabits of spectrum available to give inexpensive radios an ability to achieve point-to-point data rates of 1, 10 or 100 Gbits/second.

"Opening up gigabit data rates [will enable] real business in computer-to-computer connectivity," said Doug Lockie, executive vice president and cofounder of Endwave Corp. (Sunnyvale, Calif.) and co-chairman of the WCA task force.

Noting that 95 percent of American businesses are not connected to fiber, Lockie said wireless connectivity is the preferred medium, and Ethernet is the protocol of choice. "Ethernet is the leader in data-to-data communication," said Lockie. "Eighty percent of all data starts or ends on an Ethernet connection — all the way from metropolitan to wide-area networks. So whatever Ethernet is doing, we're going to do."

To date, millimeter-wave communication above 25 GHz has been handled in 50-MHz blocks, so an ability to deliver up to 8 bits per Hz has made data rates of up to 250 Mbits/s theoretically possible. But as frequencies move toward 94 GHz, more expensive radios with cleaner oscillators and higher-power amplifiers are required to maintain multiple bits per Hz.

Lockie said the solution is to run only 1 bit per Hz but over a much wider spectrum range, starting at 3 GHz and rising to 10 GHz over time.

"We now have our first set of recommendations in to the FCC, which has made its first set of rules," said Lockie. "The goal is to have those rules on the street in a proceeding by early summer."

The task force is proposing a point-to-point scheme, but Lockie said point-to-multipoint implementations are possible, with large buildings and the enterprise as target customers. "To get around the problem of rain fade, we'll build in a lot of link margin, with about 1,000x or 10,000x power output," Lockie said. Basestations wouldn't cost much more than cellular basestations, in the rage of $250,000 to $500,000, he said. This setup would initially support data rates of 1 Gbit/s, then 10 Gbits/s. "And by 2005/2006, we'll be at 100 Gbits/s," said Lockie.

Those frequencies and data rates will not present a bottleneck to semiconductor processes, he said. "We have all the bits and pieces to make the radio — amps that go through 200 GHz, oscillators, mixers, gain-control elements — all the building blocks exist in one form or another," he said.

Endwave itself is 40 percent owned by TRW Inc., a leading GaAs/InP foundry. "Indium phosphide and gallium arsenide work nicely at 100 GHz all the way through to 300 GHz," Lockie said.

Thus far the proposals to the FCC ask for technology-independent rules to allow room for innovation, said Lockie. "We also recommended a high EIRP [effective isotropic radiation pattern] to allow a power output similar to LMDS [local multipoint distribution system] at 55 dBW [combination of power and antenna gain]," he said.

Subsequent to the 94-GHz proceeding, the task force will also ask the FCC to allocate spectrum at 140 GHz and 220 GHz. "At 94, 140 and 220 GHz there are nice atmospheric windows," Lockie said.

The FCC is now working on details of how this spectrum is to be allocated, and is considering what portion is to be licensed, what portion unlicensed and what portion auctioned. The FCC's Office of Engineering and Technology is among those acting as advisors to the task force.

"We've just started exploring this area and we're not 100 percent it'll result in spectrum," said Lockie. "At least the FCC has taken the initiative by saying that they desire to make the spectrum available to telecoms in America."