What will Sprint do with the 800 MHz spectrum left over after it phases out its iDEN network? It will deploy LTE, but not just any flavor of the mobile broadband technology.

Sprint said today it will use the airwaves to launch LTE Advanced in the first half of 2013.

LTE Advanced, a faster version of LTE, will allow Sprint to double the speeds of the LTE network it's prepping for deployment in the first half of next year.

The next-generation network will offer speeds between 12 to 15 Mbps, compared with the 6 to 8 Mbps it expects from the LTE service Sprint is now in the process of deploying, said Iyad Tarazi, Sprint’s vice president of network development, during a press briefing at 4G World.

Sprint's LTE Advanced speeds could beat the LTE speeds of AT&T and Verizon Wireless, whose networks boast speeds of 5 to 12 Mbps.

The LTE Advanced network will be deployed in 800 MHz spectrum left over from Sprint's iDEN network, which is being phased out in favor of a CDMA-based push-to-talk service.

Sprint is in the process of overhauling its legacy infrastructure, replacing its iDEN push-to-talk service and building out LTE in its 1900 MHz G-block spectrum. The timing of the upgrade made it easier for Sprint to lay the foundation for LTE Advanced.

"We designed the network for LTE Advanced, with release 9 (LTE) in the interim," Tarazi said. The technology is currently in lab testing. LTE Advanced offers 4X4 MIMO, is faster and more efficient than its earlier iteration, and provides interference management for small cell deployment.

Sprint’s combined LTE deployments will cover 250 million people by the end of 2013. Together with the operator’s overlapping WiMAX service from Clearwire, it will offer mobile broadband coverage to 277 million people.

Tarazi said Sprint was integrating its CDMA and LTE networks to make the service as seamless as possible for its subscribers.

“LTE will look like an extension of CDMA for many customers,” he said.

That goes for voice service, as well. Sprint will offer simultaneous voice and data in the first quarter of next year, with devices that route data over its LTE network and voice over its CDMA network. By early 2013, Sprint will roll out voice over LTE and plans to debut voice call continuity (VCC) technology by the end of that year. VCC will allow voice calls to move between CDMA, LTE and Wi-Fi networks without interruption.

Tarazi hinted that Sprint’s voice offerings wouldn’t end there, saying the operator would “support all flavors of voice” beyond those listed in his presentation.