SAUSALITO, Calif. -- AT&T Inc. (NYSE: T) CTO John Donovan says that the operator is spending big on making sure that its 3G microcells work well in its network.

The CTO -- talking at the VentureBeat Mobile Summit Tuesday morning -- said that the operator is doing a lot of work behind the scenes to make sure that the femtocells don't cause interference and other problems when deployed to improve 3G coverage in a user's home.

"The amount of capital that we're putting into that is more than any other carrier as far as I'm aware," Donovan told the crowd.

Specifically, this means the operator has been working with its network controller hardware to ensure that femtocells don't cause interference when deployed. AT&T was the first operator to offer a 3G femtocell in the U.S.

In fact, Donovan eschewed talking specifically about AT&T's 4G future in favor of talking in broad terms about network capacity and growth. "I'm not making any news today," he quipped when LR Mobile asked for an update on 4G launch dates.

Instead, the raw need for more spectrum was cited as one of the key motivators behind AT&T's attempt to buy T-Mobile US Inc. for $39 billion. "The entire capacity in our network will be about six or seven weeks' worth in 2015," Donovan noted when talking about the buyout.

This is also why AT&T is still hot on Wi-Fi connections for iPhones and other devices, Donovan explained, looking back to when AT&T bought Wayport Inc. . "There were 20 million connections in the first six months of 2009," Donovan said. "Now there are 20 million connections a week."

Donovan also jokingly referenced the startup and venture-capitalist-heavy conference in a beautiful spot on the other side of the Golden Gate Bridge.

"It's always great to have a few beers and have people me tell how clueless we are," he joked at the opening of his presentation.

— Dan Jones, Site Editor, Light Reading Mobile