Using a mobile phone in an urban area is like trying to talk to a friend across a crowded room. There's a lot of interference, and background noise gets in the way of a clear signal. When you're at a party, you can solve the problem by moving within earshot. With mobile communications, your best bet is a smart antenna.

A smart antenna typically comprises an array of four to 12 antenna elements that transmit and receive signals from a base station. Unlike a traditional antenna that blankets a vast area with a signal, a smart antenna focuses radio energy in the vicinity of users. This reduces interference from other users who are accessing the same tower, and it extends the range of the signal. With less interference, service providers can increase capacity on their portion of the radio spectrum by as much as a factor of 20 (depending on the application), giving more users clearer signals.

Smart antennae are popping up all over Europe and Asia, thanks to companies such as ArrayComm of San Jose, CA. In the United States, however, there is only a smattering of these systems, many of which are the result of an agreement between Metawave Communications, in Redmond, WA, and Verizon Wireless. San Franciscobased Vivato announced plans to market an inexpensive smart antenna, which it claims will extend the range of the Wi-Fi data-transfer standard from a few dozen meters to several kilometers. For now, though, it seems that carriers are reluctant to invest the capital, so it may be a few more years before we're asking, "Can you download me now?"