Intel modifies Wi-Fi to add mileage

BERKELEY, Calif.--Intel has come up with a form of Wi-Fi that would let a laptop in San Francisco connect to the Internet from a base station in San Jose, Calif.

And there would still be about 10 miles of wiggle room to spare.

Academics and researchers from the company's labs have created a system that lets Wi-Fi signals, which ordinarily carry a few hundred feet, instead travel 100 kilometers, or more than 60 miles, said Eric Brewer, director of Intel Research Berkeley, a lab owned by the company that cooperates on research projects with the University of California at Berkeley.

"It is regular Wi-Fi hardware but with modified software," he said.

To show it works, Intel has set up a link between its labs in the downtown section of this Bay Area city and the university's Space Science Lab, about 1,200 feet up and about 1.5 miles away on Grizzly Peak Boulevard. The receiver in the office consists of a directional antenna linked to a modified--but otherwise standard--wireless access point.

The system isn't designed for the U.S. or Europe. Instead, it is part of the chip giant's efforts to bring computing technologies to people in emerging markets. The communications infrastructure in most of these countries is fairly anemic and most of it is concentrated in cities. Villages, where a large portion of the population lives, are effectively cut off from the outside world except by car, bus or footpath.

These Wi-Fi antennas, say Brewer and others, could serve as important links in a chain. Villagers would connect to a Wi-Fi antenna in their town or region, which would then relay the signals through several other towers until it came to a fiber link that connected the villager to the Internet.

In a sense, these long-range Wi-Fi antennas would perform the same function as WiMax, a long-range wireless technology that many, including Intel, are experimenting with now. The difference is that a WiMax tower costs about $15,000 to $20,000. The long range Wi-Fi towers might only cost $700 to $800.

Additionally, long range Wi-Fi could spread faster, Brewer said. The radio spectrum employed by WiMax is regulated by local telecommunications authorities. Putting up towers or offering services can require getting governmental permission.

Wi-Fi operates in the unlicensed portion of the spectrum. Thus, villages could join a network incrementally. Some networks could also leverage both WiMax and Wi-Fi: Pakistan, among other emerging nations, is investing heavily in WiMax.

Intel is considering conducting a trial of this technology, or components of it, in Uganda later this year.

How it works
One of the big differences between standard Wi-Fi and Intel's long-range version lies in the fact that the long-range signals are directional: they are tuned to travel from one antenna to another one and nowhere else. A standard Wi-Fi antenna broadcasts its signal in a 360-degree circle.

Creating a direct signal isn't easy. The antennas need to be precisely aligned with one another, and physical objects that get between the two can interfere with the signal.

"It is hard to align them," said Alan Mainwaring, a scientist at Intel Research Berkeley. "The first thing that happens is that kids play on the tower."

To that end, the company has developed a "steerable" antenna. The physical antennas themselves aren't steered--instead, the signal between the towers is guided by an electrical signal. Electrical steering also has the advantage in that the physical antennas can also move out of alignment, or even be put into the ground slightly off-kilter, without destroying signal integrity.

The lab has made one system out of "L" brackets and wood, among other components, and will come out with a second generation of antennas in the relatively near future. (Some of the technology for the steerable antenna comes from professor Alexey Umnov of Nizhny Novgorod State University in Russia. Intel has research facilities in that city, too.)

Additionally, a lot of the protocols and procedures in ordinary Wi-Fi communication are eliminated. Handshaking, which allows a PC and a wireless router to link up in an ordinary Wi-Fi network, and collision detection are eliminated.