We’ve been seeing “LTE-A” markings on handsets coming out of Korea, and it looks like we may soon be seeing similar markings here in the US. AT&T has become the first of the US carriers to launch LTE-Advanced coverage. But before you start checking your current handset, or thinking about what you can upgrade to — the coverage is rather limited at the moment.

AT&T is said to be using something called “carrier aggregation” which basically bonds two 4G networks. More to the point though, this means a large bump in speeds. Potential download speeds of up to 110Mbps. This all sounds good so far, but we do need to revisit the limited coverage aspect. For now, AT&T has LTE-A in the Windy City, Chicago.

Kris Rinne, SVP of Network Technologies at AT&T, in speaking with GigaOM, mentioned how this setup is actually live in “several” markets. Sadly though, Rinne was only mentioning Chicago by name. And for those wondering why we have yet to see a massive promotion launched by AT&T touting these new speeds — one can assume they are holding back given few users will be able to take advantage.

At present the one and only device AT&T has with the necessary support is a mobile hotspot. Specifically, the Unite which was launched in the later part of last year. AT&T has yet to offer specifics here, but it is believed the Galaxy S5 will bring the necessary support for AT&T LTE-A. The Galaxy S5 is expected to arrive in the US beginning in April. Of course, as the network expands, so will device support, and vice versa.