It hasn't been easy to bridge differing LTE network types in one phone; ZTE's attemptrequires a reboot, for example. Samsung claims to have solved that problem with new dual-mode LTE versions of the Galaxy S 4 and Galaxy S4 Mini. Both devices can switch between the common FDD-LTE standard and TDD-LTE without restarting, and they'll automatically hand over any ongoing data sessions or voice calls. The advantages are potentially huge for both roaming and bandwidth -- travelers are more likely to stay on 4G, and providers running both FDD and TDD can switch customers to whatever network has the most capacity. Samsung hasn't said where and when the dual-mode Galaxies will be available, although TDD-LTE's worldwide reach (including the US) suggests that the smartphones could soon be commonplace.

http://www.engadget.com/2013/07/31/s...dual-mode-lte/