This is actually less unreasonable than it seems at first.
The Vo WiFi spec only defines handover procedures for networks that implement VoLTE, but VoLTE roaming was historically almost nonexistent, although the situation is improving somewhat.
This means that if you go out of range of your WiFi router, your cell phone has no idea how to request a handover from the network, and the call drops.
The Vo WiFi spec only defines handover procedures for networks that implement VoLTE, but VoLTE roaming was historically almost nonexistent, although the situation is improving somewhat.
This means that if you go out of range of your WiFi router, your cell phone has no idea how to request a handover from the network, and the call drops.