Verizon introduced its 4G LTE network last year, and AT&T is launching its own by the end of this summer. But just because they are using the same wireless networking standard doesn’t mean that devices designed for one will be able to use the other.
The two carriers are using different frequencies for their LTE services. AT&T’s phones are going to use 704-746MHz, but Verizon’s phones use 746-787MHz. According to a Verizon spokesperson, the carrier has no plans to add support for AT&T’s frequencies to its devices.
It’s also not clear if any of the devices designed for the LTE networks in the U.S. will be able to roam onto the LTE networks being built in other countries. This will depend on what frequencies these countries choose.
A Morass of Incompatibilities
This is a disappointment to those who have been hoping that with most of the top carriers in the U.S. switching to LTE, then most of the incompatibilities between handsets designed for different carriers would go away.
As it stands now, Verizon and Sprint use the CDMA/EV-DO standards as their voice and 3G data networks, and AT&T and T-Mobile use GSM/HSPA. That puts these four carriers into two separate camps. And it’s more complicated than that, as T-Mobile and AT&T use different frequencies for their 3G networks, so a device designed for one can’t connect to the other’s high-speed data network. Also, Sprint chose WiMAX for its 4G standard, rather than LTE.
But AT&T, Verizon, and T-Mobile have all committed to LTE, and there are rumors that Sprint is going to switch to this standard as well. This raised the hopes of many that someday any smartphone could be used with any carrier in the U.S., something Europeans take for granted. But it seems it’s not going to happen, at least not any time soon.
In the short term, the fact that both AT&T and Verizon are going to have LTE networks wasn’t going to bridge the gap between them, no matter what frequencies they used. This is because LTE is a data-only standard and phones that use it will also need to be able to connect to a wireless voice network. Verizon’s handsets use CDMA for this, while AT&T’s will use GSM.