T is a phenomenon well known to people who drive through urban high-rise canyons. Just as you stop at a traffic light, the car radio loses its signal. Once the light turns green, the car only has to creep forward a few feet to restore the radio reception.

Those dead spots, which can also cut off cellphone calls and mobile computer communications, are often caused when signals bounce wildly off the surrounding buildings. This scattering creates pockets in which two reflections of the same signal collide and cancel each other out.

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Avoiding the undesirable effects of multipath, as this scattering effect is formally known, has long been a preoccupation of people who design wireless communications systems. Now, however, a system developed by Bell Labs actually embraces radio reflections not only to improve reception but also to boost the speed of wireless networks. Prototypes of the system, called Blast, can send data over third-generation, or 3G, cellphone networks at rates about eight times those of 3G.

"Normally multipath is the source of confusion, it's the enemy," said Robert W. Lucky, who recently retired as vice president for applied research at Telcordia Technologies and is familiar with the Bell Labs work. "Here you put the confusion back together Humpty Dumpty style. It's like getting something for nothing."

Gerard J. Foschini, a 40-year veteran of Bell Labs, came up with the theory behind Blast about a decade ago while working on a long-term project to find the limits of a wide variety of technologies. As part of that project, he reviewed the work of Claude Shannon, the Bell Labs mathematician who published a paper in 1948 that established the field of modern information theory. Dr. Shannon's work still provides the basis for much information theory, including the notion of system capacity limits.

"He found the ultimate limits," Dr. Foschini said. "But he was basically dealing with one transmitter and one receiver. It was obvious to us that we could deal with many transmitting antennas and many receiving antennas for the same transmission."

So Dr. Foschini began developing mathematical models to see whether sending data through arrays of antennas would expand network capacities.

Antenna arrays have long been used in radar systems. But Dr. Foschini said that radar arrays are used to focus radio beams, whereas he wanted to scatter them. He hoped to discover whether wireless capacity could be boosted by dividing up data in space as well as time. Rather than point-to-point communications, his plan was to create volume-to-volume exchanges.

He had found through mathematical research that the concept would not work if the transmitter had only a single antenna. "If you send the same signal from one antenna many times all radiating in the same band, you come out statistically right where you started," Dr. Foschini said.

Instead, he developed a system that divided data into multiple streams that were then transmitted on the same frequency by several antennas. At the receiving end, the different streams of data were picked up by other antenna arrays.

Normally more than one transmission on a single radio frequency produces nothing but electronic noise. But Blast can make sense out of the noise because of the physical separation of the antennas sending the messages. Processing software reassembles the scattered data streams into their original form.

When Dr. Foschini tested the plan mathematically, the results were surprising. "We found the capacities were enormous - far, far in excess of what people were thinking of,'' he said. "If you put more and more antennas at the transmitting end, the capacity kept increasing. We were coming out with such ridiculously large capacities that at first, we didn't believe it."

Prototype systems proved that the experiments were correct. Each additional antenna added another element of space and because of that, additional capacity.

Just as surprising was the finding that the reflections that plague current wireless systems actually expanded the capacity of Dr. Foshini's system by effectively introducing more points in space. "Heavy scattering, which I always thought was a bad thing, is with this a good thing," he said. In fact, he anticipates that Blast-based wireless systems will work more effectively in Manhattan rather than "somewhere where it's flat as far as the eye can see."