WiFi calling handoff to cellular drops calls mid-sentence

When a smartphone on a WiFi call moves out of WiFi range (leaving home, walking to the car), the call must hand off from WiFi to cellular. Unlike cellular-to-cellular handoff which is seamless (managed by the carrier network), WiFi-to-cellular handoff has no standardized protocol. The phone must detect WiFi degradation, establish a new cellular bearer, and transfer the VoIP session — often dropping the call entirely for 2-10 seconds or disconnecting it. So what? Business calls made from home on WiFi calling drop when the person walks to their car or garage. So what? They have to call back, looking unprofessional and losing the flow of conversation. So what? People learn to disable WiFi calling entirely, even though WiFi calling provides better indoor audio quality and is essential in buildings with poor cellular coverage. So what? They suffer poor indoor cellular reception instead, with dropped words and metallic audio quality. This persists because WiFi calling (VoWiFi) was designed primarily for indoor use and handoff to VoLTE requires carrier-side ePDG (evolved Packet Data Gateway) coordination that many carriers implement poorly. Apple and Android handle this differently, and no carrier consistently delivers seamless handoff.