VOICE over LTE or some would call it HD voice is basically coursing voice calls over the LTE network of a mobile carrier. It's the equivalent of discarding the old switch board based handling of voice calls.
VoLTE is, by my understanding, turning analog voice into a stream of 1s and 0s. Analog becoming digital data and, as a result, allowing users to experience clearer voice calls. And while being in a voice call still use the data portion of the stream so users can still browse the internet while on a call.
But that's how it is now, you say. Actually, it's not. Give it a try. Make sure first that you have LTE signal on your phone, put your phone in front of you and make a call. Watch that "LTE" signal label turn to 3G then 2G. Why? Because LTE was primarily created to be a data carrier and not a voice carrier and 3G and 2G were created for voice. Hence, the signal switching.
A couple of days ago, in an article on Manila Bulletin, Smart announced it successfully made a VoLTE call. This is great news if you ask me. It's a big push forward toward being toe to toe with other mobile networks around the world offering advanced mobile technology solutions. I'm pretty sure Globe will not be far behind.
Although, Smart is yet to roll out this feature to its entire network, exciting times lie ahead. But before Smart or Globe can even implement this fully, they'll need to roll out LTE to its entire network. However it happens, it will be very good for all of us clients. It won't be long when things are fully implemented and it's going to be awesome.