Here in the US the mobile carriers are finally getting something done with respect to rolling out HDVoice. T-Mobile has been offering HDVoice since January of 2013. As I’ve mentioned previously, I’ve been able to try this myself using a Nexus 5. They added a little sport to the game by launching VoLTE in Seattle earlier this month.
Sprint is trialing HDVoice in limited markets pending a national rollout in June. AT&T has launched VoLTE/HDVoice in some mid-western markets. Verizon must be feeling laggard as they recently started some PR/social media hand-waving with respect to their VoLTE/HDVoice initiative.