Conan Kudo

The LTE network has no whitelisting, but the CDMA network does. Also, all LTE devices are supposed to be SIM unlocked from purchase. Until VoLTE comes online this fall, true LTE interop won’t become available in the U.S. Right now, only T-Mobile USA has implemented it in the newest version of their Wi-Fi Calling solution. If you can figure out the SIP information for it, you can provision VoLTE to work on any unlocked UMTS phone (and it will successfully work over EDGE, HSPA+, LTE, and Wi-Fi).

T-Mobile US executives are primarily paid with Deutsche Telekom stock, but they do have a small salary as well.

Korea uses a standard frequency band. The U.S. does not.
Currently, non-Qualcomm LTE chips support LTE 800(EU), 850(Americas/Asia), AWS, 1800(EU/Asia), 1900(A-F, Americas/Asia), 2100(Asia), 2600(EU/Asia). LTE 700(AT&T/Regional US), LTE 750 (VZW), and 1900(A-G, Sprint) are not supported by any non-Qualcomm radio chip.

They have to re-engineer the radio interface system to support more bands, yes. Currently, non-Qualcomm LTE chips support LTE 800(EU), 850(Americas/Asia), AWS, 1800(EU/Asia), 1900(A-F, Americas/Asia), 2100(Asia), 2600(EU/Asia). LTE 700(AT&T/Regional US), LTE 750 (VZW), and 1900(A-G, Sprint) are not supported by any non-Qualcomm radio chip.

U.S. Digital Dividend spectrum (used by AT&T and Verizon) and Extended PCS spectrum (used by Sprint) are only supported by Snapdragon SoCs for LTE. In South Korea, they use Cellular 850 spectrum for LTE (which is the same 850MHz band used for 3G by AT&T and Verizon in the U.S.).

They can’t. Only Snapdragon supports U.S. Digital Divided and Extended PCS (which are used by AT&T, Verizon, and Sprint).