AT&T Mobility (NYSE: T) has deployed its 2.3 GHz WCS spectrum for LTE service in a handful of markets, fulfilling its goal of launching service on the spectrum this summer. However, it's unclear how widespread the rollout is at this point or how quickly it will proceed to bring extra capacity to the carrier's network.

"We have started the deployment and already have a couple markets deployed," AT&T said in a statement to FierceWireless. In March, Tom Keathley, senior vice president of network and product planning at AT&T, said that during the summer the company expected to start altering its network gear in certain markets to get the deployment rolling. AT&T has long said it would deploy the spectrum in 2015 but had never given a more official timetable.

It's not clear how many markets or which ones AT&T has turned on WCS spectrum for LTE, and an AT&T spokeswoman did not immediately respond to a request for comment. However, Keathley had indicated the airwaves were likely going to be deployed first in dense, urban areas since AT&T views WCS as a "capacity layer" on top of its nationwide 700 MHz deployment. Tower companies have been eagerly awaiting the capacity overlay buildout as a sign that AT&T is going to ramp up its capital expenditures after several quarters of slower spending.

"We'll continue to deploy WCS spectrum to meet our customers' needs while providing the best possible network experience," AT&T said in regards to the pace of the deployment going forward.

Samsung Electronics' recently-introduced Galaxy S6 Edge+ and Galaxy Note 5 devices are two the phones that support WCS bands. "We expect additional smart phones to support WCS by the end of the year," AT&T said.

AT&T in 2012 acquired $600 million worth of additional WCS spectrum from NextWave. AT&T also inked agreements last year to purchase all of Sprint's (NYSE: S) WCS spectrum licenses. The carrier had planned to use some of that spectrum to offer in-flight Wi-Fi services, but last year scrapped that plan.

Keathley has said it will not be a major undertaking to add 2.3 GHz capabilities to AT&T's network. He said in March that all of the antennas the company has deployed recently are "broadband antennas" and include support for the WCS spectrum. So to add 2.3 GHz support will require adding just another remote radio head at cell sites, he said.

In addition to the 2.3 GHz band, AT&T is also using 700 MHz and 2100 MHz AWS spectrum for LTE. (AT&T is also using carrier aggregation to combine 700 MHz and 2100 MHz in some markets). AT&T is also refarming its 1900 MHz PCS spectrum for LTE service in some markets.

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