The AT&T 4G LTE network is really solid in the Chicagoland area. I never had any issues connecting to the internet or making calls with the Nokia Lumia 1020. Our peak download on the AT&T 4G LTE network was impressive at 30.56Mb/s and our upload was maxed out at 14.23Mb/s. On all but one of the Speedtest.net runs we saw great download speeds, on that one we had a download speed of 4.16Mb/s, but a moment later we reran the test and hit 11.62Mb/s. Over all I would say that the network performance with the Nokia Lumia 1020 was spot on with what we have come to expect from the AT&T 4G LTE network.