AT&T's 5G wireless network just got much more tangible. The carrier has announced that its ultra-fast wireless will launch in two cities, Austin and Indianapolis, sometime later in 2017. And while it's still early days, the company is confident enough to set some performance expectations. Initially, these 5G areas will deliver peak speeds of 400Mbps or better. And there's definite room for it to grow -- carrier aggregation and other techniques should push that to 1Gbps in "some areas" this year.