LIVE FROM CTIA SUPER MOBILITY WEEK: T-Mobile US plays the role of feisty outsider in its service offerings, but comments by Mark McDiarmind, the operator’s VP of radio network engineering, showed the same mentality is present on the network side as well.

The T-Mobile executive was speaking ahead of the latest instalment of the operator’s Uncarrier strategy being unveiled. Dubbed Wi-Fi Unleashed, the operator said it will enable VoWi-Fi calling on all new smartphones in the future.

The service will allow users to make and receive voice calls even when cellular coverage is spotty, for instance inside buildings.

The move is consistent with comments made earlier by McDiarmind in talking up the operator’s innovation on voice. The operator is a supporter of HD voice, both on 3G and 4G.

In addition, he said the operator’s network integration meant there is seamless coverage between VoWi-Fi and VoLTE.

Several years ago T-Mobile US famously, or infamously, championed HSPA+ as equivalent to 4G, an earlier example of it courting controversy.

“Three or four years ago, there was no voice solution for 4G, it was immature. HSPA + was the sweetspot,” said McDiarmind.

Fast forward and the operator used the windfall from its failed takeover by AT&T to bankroll the refarming of 1.9 GHz GSM spectrum for HSPA+, a smart move that used a rival’s funds to bolster its own competitive position.

T-Mobile US used these moves to minimise network costs and squeeze the most out of the spectrum it did have.

At its Uncarrier event, the operator also announced its Personal Cellspot, a Wi-Fi router that will prioritise voice calls at HD quality.