It
Dude, just stop. You couldn't be more wrong and all you're doing is confusing people by continuing. You don't even know the difference between VoLTE and HD Voice. Here's a starting point: they're 2 separate things, not related.
HD Voice is a codec. It digitizes your voice for transmission. It is AMR-WB, and it works on GSM (2G), and UMTS (3G). It has a CDMA equivalent, VMR-WB that works on 1x Advanced. It's been deployed for almost 2 years in the US alone. In order to complete an HD Voice call, you need 2 HD Voice capable devices in a supported deployment. For Verizon, this is solely on LTE.
Wideband audio
https://en.wikipedia.org/wiki/Wideband_audio
VoLTE is only, repeat only, the carriage of voice over LTE. It is meant to replace all former technologies. It is not limited to only being able to call other LTE devices. The calls go out as normal. It was developed to be better on data usage than VOIP, optimized for LTE; to maintain QoS so that voice calls take precedence over data calls; and to have a common IMS core to allow it to compete with OTT VOIP. To complete a VoLTE call, you need LTE coverage and a device that supports VoLTE... And you can call *anyone*[/QUOTE