Smartphones have been too much of a good thing for AT&T, as users like them so much that they hog network space. To deal with the problem, AT&T says it will institute a curb on wireless data usage soon.

The chief culprit, of course, is the iPhone, whose popularity has caused its users to download so much data that the AT&T network has been compromised.

The problem was aired Wednesday at an investors conference where Ralph de la Vega, chief executive of AT&T Mobility, said that the firm's network in New York City and San Francisco is "performing at levels below our standards." The firm has been upgrading its network, but the use of smartphones, and particularly the iPhone, is causing an exponential rise in data usage. De la Vega said that 3% of smartphone users are using 40% of data traffic.

De la Vega didn't spell out any exact method of trimming usage, but he indicated something will be announced on the issue soon, according to media reports.

The problem has been growing and isn't unique to AT&T. In October, FCC chairman Julius Genachowski said there is a "looming spectrum crisis." Genachowski proposed a series of solutions to help stem the coming mobile data tsunami, but even with additional spectrum and other aids like femtocells, he wasn't optimistic that a data crunch can be avoided.

"Even with innovative spectrum policies and innovative new technologies," Genachowski said, "experts believe we are way too likely to be caught short."

De la Vega said the AT&T network problem will be fixed, although he indicated improvement would be gradual.

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