How to use of 3g video calling
The Verge confirms in its testing with a review unit of the new iPad with 4G LTE that FaceTime video calling remains limited to Wi-Fi networks despite the fact that LTE offers greater bandwidth than many Wi-Fi networks
As the report notes, Steve Jobs claimed during FaceTime's introduction at the iPhone 4 media event in June 2010 that Apple still needed to work with carriers to support FaceTime over cellular data networks and that the feature would consequently remain Wi-Fi-only at least through 2010. Well into 2012 and with 3G now giving way to LTE on the new iPad, it seems that carriers are still unwilling to allow FaceTime calls to be transmitted natively over their networks, presumably due to concerns about increased data usage and strained network capacity.
As the report notes, Steve Jobs claimed during FaceTime's introduction at the iPhone 4 media event in June 2010 that Apple still needed to work with carriers to support FaceTime over cellular data networks and that the feature would consequently remain Wi-Fi-only at least through 2010. Well into 2012 and with 3G now giving way to LTE on the new iPad, it seems that carriers are still unwilling to allow FaceTime calls to be transmitted natively over their networks, presumably due to concerns about increased data usage and strained network capacity.