Question: In an IMS Collaborative Session, what is a prerequisite for transferring the Controller UE role to another UE during the session's lifetime?
Option 1: The new UE must be from a different IMS subscription under the same operator.
Option 2: The new UE must have registered a Public User Identity sharing the same service profile as the current Controller UE.
Option 3: The new UE must initiate an Inter-UE Transfer procedure without establishing a Collaborative Session.
Option 4: The new UE must be authorized by the Hosting SCC AS through a separate authorization process.
Explanation: This is correct because, according to IMS Service Continuity principles, for the Controller UE role (Collaborative Session Control) to be transferred to another UE during a Collaborative Session, the new UE must have registered a Public User Identity that shares the same service profile (and thus belongs to the same IMS subscription) as the current Controller UE, ensuring continuity and consistency in session management.