CHICAGO -- 4G World 2011 -- Sprint Corp. (NYSE: S) is cracking along with plans to speed up its Long Term Evolution (LTE) network even before the initial 4G service goes live in 2012.

Sprint announced plans on Tuesday morning to start upgrading its network to faster LTE-Advanced technology in the first half of 2013. Earlier this month at its Network Vision strategy day, the third-ranked U.S. operator revealed plans to deploy LTE in the vacant G-Block of 1900MHz PCS spectrum that it owns. The rest of its PCS spectrum is used for its CDMA services. (See Sprint to Launch LTE by Mid-2012 and Sprint Promises LTE Devices in Early 2012.)

"It's in the labs now," says Iyad Tarazi, VP of network development & engineering at Sprint. The technology gets faster uploads and downloads by using a 4x4 antenna array on the devices and in the infrastructure, while implementing improved interference techniques.

Tarazi says that the operator will be looking at larger devices rather than handsets for initial device offerings in 2013. "We believe that tablets are the right format, there's more real estate to work with," Tarazi tells Light Reading Mobile.

Larger smartphones -- like the current crop with 4.3-inch displays -- may also prove to be a viable platform as well over time. "We're debating that," he says.

LTE Advanced is supposed to offer maximum download speeds of 1 Gbit/s stationary and 100 Mbit/s to users on the move. There are a lot of variables, however, in those bland theoretical speeds. Some of the tests so far undertaken use 8x8 antenna arrays and up to 60MHz of bandwidth to achieve maximum speeds of nearly 1 Gbit/s.

Sprint will be using two 5MHz paired channels for its early LTE deployment. It should be able to move to two 10MHz channels if and when the LightSquared 1.6GHz L-Band spectrum becomes available. Sprint has previously said that the PCS spectrum will give it capacity through 2014 and LightSquared will take it through 2015.

What this means in the real world is that we don't yet have any solid idea of how fast LTE Advanced will be on Sprint's network. It is, however, likely to be way slower than some of the crazy fast trial speeds seen so far.

— Dan Jones, Site Editor, Light Reading Mobile