公开(公告)号：WO2022098475A2

公开(公告)日：2022-05-12

申请号：PCT/US2021/054528

申请日：2021-10-12

Applicant: APPLE INC.

Inventor： RAMAPPA, Shashanka Totadamane ,  KISS, Krisztian ,  CHERIPALLY, Madhusudhan ,  LEE, Michael ,  PANGI, Pradeep ,  KRISHNAPERUMAL, Rajkumar ,  PRAKASAM, Sridhar

IPC: H04W76/18 ,  H04W76/50

Abstract: A technique for establishing a voice call including receiving an indication that the first wireless system supports emergency service fallback, receiving an indication to establish an emergency voice call, transmitting an emergency service request to the first wireless system, determining that an unexpected error has occurred, selecting a second wireless system based on the determination that the unexpected error has occurred, and connecting to the second wireless system to complete the emergency voice call. Additionally, a technique for cancelling a voice call including receiving an indication that the first wireless system supports emergency service fallback, receiving an indication to establish an emergency voice call, transmitting an emergency service request to the first wireless system, receiving an indication to cancel the emergency voice call, and cancelling a connection to a second wireless system.