AT&T LTE Plans Too Small for LTE iPhone?
The only way to make an LTE iPhone viable for AT&T this summer would be if AT&T users could roam on to Verizon Wireless 's 4G network, and Verizon isn't yet saying anything one way or the other about a roaming agreement. My guess is there isn't one between the rivals. (See AT&T's LTE Plans Provide Clue to iPhone 5 Launch and New Networks Hint at an iPhone 5 Timeline.)
Verizon would welcome the LTE iPhone on its network, however, as its first 4G smartphone has proved to be a hot item. Apple would have to build an LTE/3G CDMA dual-mode version of the device for Verizon, but would risk alienating its one-time exclusive partner if it didn't have an LTE/3G GSM version ready at the same time. (See Verizon Charges Up 2nd LTE Smartphone.)
We know there are other issues possibly at play (or not) in holding up the LTE iPhone, but coverage is a big one. Until AT&T's LTE network is more nationwide, which isn't going to happen in 2011, I wouldn't hold out for the LTE iPhone on any U.S. carrier this year.
— Sarah Reedy, Senior Reporter, Light Reading Mobile