“HD Voice is part of our voice over LTE strategy,” Rinne said, at the VentureBeat Mobile Summit. Addressing issues with call quality over the years he said, "I think we’ve taken that off the table in terms of a competitive challenge."
Additionally, the company says that it will start working on 'advanced LTE' which will reduce interference and bond traffic together from various frequencies. It's also investigating working with messaging services such as Facebook and notes that it has made network programming hooks available to even those creating services that rival its own.
At it's launch event for the iPhone 5, T-Mobile noted that it would support HD Voice. The company is set to start selling the iPhone 5 on April 12th.