OVERLAND PARK, Kan. –- Sprint Corp. (NYSE: S) will deploy Long Term Evolution (LTE)-Advanced by 2013 and begin refarming its 800MHz spectrum for LTE in 2014, filling in two important pieces of its Network Vision puzzle.

Speaking at a media event here at Sprint headquarters, several executives gave a progress report on Sprint's network transformation, including how it will morph its iDEN network into LTE while also building out a zippier LTE-Advanced network in less than two years. (See Ready or Not, Here Comes LTE-Advanced.)The U.S.'s third-largest carrier is in the process of migrating its push-to-talk subscribers from the iDEN network on 800MHz to CDMA in order to free up the spectrum and repurpose it for LTE. Sprint plans to complete the migration in 2013 and deploy LTE on 800MHz by 2014, SVP of Networks Bob Azzi told reporters Thursday.

"2014 is the big year," he said.

That is dependent, however, on first receiving Federal Communications Commission (FCC) approval to refarm the spectrum. Azzi is confident that won't be a problem because, he said, it's a standard process and 800MHz has already received 3GPP certification as an LTE band. The bigger limiting factor may actually be how quickly it can get loyal "button users" to vacate the spectrum.

So far that's been going relatively smoothly. Sprint started with 20 million iDEN customers, but is down to less than 6 million today. Azzi said that Sprint Direct Connect has been the missing piece of the puzzle to convince the primarily enterprise people who rely on the walkie-talkie-like service to move from iDEN to CDMA. These users can get the button on CDMA, but also have access to more push-to-x functionality and 1X advanced voice. (See Sprint Details iDEN's Death March .)

"They were looking for an evolutionary path, and they knew [iDEN] was a dead-end," Azzi said. "They needed a path to the future, but they couldn't give up the button."

Even so, the process of completely decommissioning iDEN will take a few years. This year, Sprint will shut down 9,600 cell sites, which represents about a third of the total. By 2013, the rest will go.

At that time, Sprint can turn its attention to LTE-Advanced, which VP of Development and Engineering Iyad Tarazi said is ready to go today, but will launch in the first half of 2013. The carrier is already deploying 2x2 MIMO [multiple-input and multiple-output] antennas and is going to 4x4 MIMO. When LTE-Advanced comes online, Sprint will have tablets ready for it, he said. Azzi added that it will have its roadmap for LTE-Advanced devices laid out by November. (See Sprint Plans LTE-Advanced Launch in 2013.)

"We're ready for LTE-Advanced," Tarazi said.

Part of the rush to move to the advanced 4G network is because Sprint will be operating LTE on 5x5MHz channels, while its competitors -- AT&T Inc. (NYSE: T) and Verizon Wireless -- run on 10x10 channels. Azzi says that in the real world, where peak speeds aren't the norm, the competitive offering will be the same. Once it fills up its 5x5 blocks, it'll have other options to supplement capacity, including using Clearwire LLC (Nasdaq: CLWR)'s TD-LTE network for offload and looking at other spectrum hosting deals like the one it nixed with LightSquared . (See Sprint Scuttles LightSquared Deal .)

"We have half the customers of Verizon, so even with a fully loaded network, we end up in the same place," Azzi said. "As we fill it up, we don't want speed to degrade, so we'll add the other spectrum bands to supplement that growth."

— Sarah Reedy, Senior Reporter, Light Reading Mobile