Carrier aggregation is one of those next level LTE-Advanced technologies that has slowly become the new standard at the nation’s top wireless carriers. T-Mobile said it started toying with carrier aggregation all the way back in 2014. Verizon last August crowed over its nationwide launch of the feature, and Sprint and AT&T have also moved ahead with deployments of the technology as well. Even C Spire, the nation’s sixth-largest wireless carrier, is now using carrier aggregation to boost speeds in Mississippi.

Most of these efforts center on two- and three-channel carrier aggregation, but AT&T is pushing things a step further. Back at Mobile World Congress in March, AT&T’s VP of RAN and Device Design Gordon Mansfield told Wireless Week the carrier had four carrier aggregation in its sights for the second half of this year. This week, Mansfield said AT&T is well on its way to that goal.

“We are actively testing four carrier aggregation and are on track for this to start showing up in devices in the near future,” Mansfield commented. “We have rolled out 256-QAM and 4X4 MIMO in a significant part of our network already and this makes up some of the functionality required as a first step in our evolution to 5G.”

The latter part of Mansfield’s update is a reference to AT&T’s 5G Evolution plan, which calls for the carrier to utilize carrier aggregation and Licensed Assisted Access (LAA) to enable theoretical peak speeds of up to 1 Gbps before the end of this year. Mansfield in March noted the unlicensed element will be key to hitting the gigabit mark.

“You can get close, you can get up to several hundred (Mbps) with just the macro network and the licensed spectrum, but the way you get to a gigabit is you use licensed spectrum with 4×4 MIMO and 256-QAM and you bring in LAA with unlicensed carriers. And in that case it will actually be 4CA,” he explained.

Mansfield said previously the upgrades to four carrier aggregation will be made via software updates in the carrier’s network. On the device end, Mansfield indicated at MWC that some LTE-Advanced capabilities will be available on new handsets right out of the box. But other technologies, like LAA, will have to be added through an over-the-air software update pushed out over the network later in the year, he added.