Question: In a HANDOVER FROM UTRAN COMMAND with an activation time later than the procedure delay, when must the UE be ready to transmit on the new channel of the new RAT?
Option 1: Immediately after receiving the command
Option 2: At the designated activation time + interruption time
Option 3: Within Dhandover seconds from the end of the last frame containing the command, regardless of the activation time
Option 4: After the procedure performance value (50 ms) from the end of the command
Explanation: According to the specifications for handling a HANDOVER FROM UTRAN COMMAND with an indicated activation time later than the procedure delay, the UE must synchronize its transmission readiness with the specified timing on the new channel. This means the UE waits until the designated activation time and then adds the interruption time before being ready to transmit. This ensures seamless handover without premature or delayed transmission on the new RAT (Radio Access Technology) channel.