Sourav_Satvaya My NP(1) is able to make a call in aeroplane mode with Wi-Fi activated. So long as you have previously connected to the cellular network and have wi-fi calling enabled, it will be set up to work using IMS - just like VoLTE.
What is VoWi-Fi?
VoWi-Fi stands for Voice over (EPC-integrated) Wi-Fi. VoWi-Fi is a complementary technology to VoLTE and utilises IMS technology to provide a packet voice service delivered over IP via a Wi-Fi network. Where possible, VoLTE calls may be seamlessly handed over between LTE and Wi-Fi and vice versa. Conversational video is also possible via Wi-Fi (see ViLTE).
How does Wi-Fi calling work?
Wi-Fi calling will work similarly to other Wi-Fi enabled voice over IP (VoIP) applications – such as Skype or WhatsApp – albeit with slight differences. Wi-Fi calling works through transmitting the same cellular data packets as Wi-Fi VoIP through a Wi-Fi connection and across the internet. From the internet, data is passed to the cellular network and then back to the answering party. Wi-Fi calling must be supported by the smartphone to work. The service is a newer version of the Generic Access Network (GAN) protocol.
