NEW YORK (AP) — AT&T says the shutdown of its "2G" wireless network will be complete by the end of 2016, a process that will force customers with older phones to upgrade to "3G" or "4G" handsets.

AT&T said in regulatory filing Thursday that's shutting down the older network, which doesn't support high data speeds, city by city. It said earlier this year that the process has started in New York City, and it's trying to move 2G subscribers to new phones.

By shutting down 2G and using the same space on the airwaves for 4G, AT&T can increase data capacity by more than a hundred-fold.

Other companies are also "refarming" 2G spectrum. Sprint Nextel is shutting down the Nextel 2G network and moving subscribers to Sprint 3G.