AT&T and Verizon 4G LTE phones may not work on each others’ networks
It looks like the switch to 4G LTE networks may not fix one of the big quirks of the U.S. mobile market: That phones designed for one network rarely work on other networks.
Verizon may be designing its phones to only run on Verizon’s very specific wireless frequency, locking out all other possible carriers. Verizon and AT&T both run their LTE networks in the 700-MHz band. But Verizon’s network is mostly in 746-787MHz, while AT&T’s will be primarily in 704-746MHz. [...]
The result is an incompatible welter of devices, likely to continue long into the future. If you’re dreaming that LTE would allow one device to work on several U.S. networks, dream on.
You may recall that Verizon’s 700 MHz spectrum, won in the 2008 FCC auction, includes some mandatory “open” usage provisions: That it must be open to any compatible devices or applications that want to access it. But that doesn’t mean Verizon has to make it particularly easy for people to use non-Verizon devices on its network, especially the mass-market gadgets that archrival AT&T will be selling.
And while it may be technically possible for handset makers to design phones that work on every possible combination of LTE frequency and 3G fallback technology (CDMA and GSM), it doesn’t mean they will — for a variety reasons, ranging from carrier orders to design considerations.