Anyone who's suffered broken cell-phone connections in urban areas already choked with voice traffic might doubt the imminence of the wireless Web. But researchers predict that a new technology called "multiuser detection" could greatly expand cell towers' capacity-increasing their range, their data transmission rates or the number of users they can handle.

Multiuser detection disentangles cell phone signals that interfere with each other, and "everybody who has an interest in cell phone systems is working on the implementation," says Peter Okrah, a researcher with wireless-equipment supplier Motorola. Ericsson, Nokia, Lucent Technologies, Intel and Microsoft have all investigated the technology, though the first to market may be smaller competitors such as industry supplier Ascom of Berne, Switzerland, or Mercury Computer Systems of Chelmsford, MA.

The central problem of cellular telephony is how to let users access the same tower without breaking up each other's calls. The most efficient solution is to assign a unique "code," or combination of radio frequencies, to each phone; a tower can key onto any one code and screen the others. In practice, however, buildings and other obstacles knock signals out of sync and cause them to interfere with each other.

The solution: subtraction. Since a tower knows the codes for all its current calls, it knows what the interference looks like and could remove it from a distorted signal. But that requires a lot of processing power-or some mathematical shortcuts.