Apple has announced several new wireless features for the iPhone 6 and iPhone 6 Plus, including faster Wi-Fi that achieves speeds of up to 3x faster than previous models. New LTE technology is also preset, allowing speeds of up to 150 Mbps.
Perhaps more importantly, Voice over LTE calling has been enabled, and can take advantage of the new Wi-Fi hardware to place calls over a Wi-Fi connection while still using your cellular phone number. T-Mobile is one of the first carriers rolling this out in the United States.
The iPhone 6 will operate on over 200 carriers on 20 different LTE bands.