The study is to investigate solutions to minimize call setup failure and improve user experience for VoLTE subscriber in LTE with bad coverage.
The study shall consider the scenarios where UE is both PS and CS registered or only PS registered and UE is already IMS registered initially.
The study will cover at a minimum the following scenarios:
LTE with bad coverage is overlaid with 2/3G CS coverage.
LTE with bad coverage is overlaid with WiFi access.
LTE with bad coverage is overlaid with both 2/3G CS coverage and WiFi access.