Question: In a Cell Broadcast Service (CBS) scenario, when an Access and Mobility Management Function (AMF) receives a CANCEL RESPONSE from an NG-RAN node without a Broadcast Cancelled Area List Information Element (IE), how does the AMF handle this in the STOP-WARNING-INDICATION-NG-RAN message?
Option 1: The AMF omits the NG-RAN node ID from all lists in the STOP-WARNING-INDICATION-NG-RAN message.
Option 2: The AMF includes the NG-RAN node ID in the Broadcast Cancelled Area List of the STOP-WARNING-INDICATION-NG-RAN message with a special indicator for 'no area'.
Option 3: The AMF includes the NG-RAN node ID in the Broadcast Empty Area List of the STOP-WARNING-INDICATION-NG-RAN message.
Option 4: The AMF sends separate STOP-WARNING-INDICATION-NG-RAN messages for each type of response (with and without Broadcast Cancelled Area List IE).
Explanation: If an AMF receives a CANCEL RESPONSE from an NG-RAN node without a Broadcast Cancelled Area List IE, the NG-RAN node ID is included in the Broadcast Empty Area List. This ensures all responses are accounted for and properly communicated to the Cell Broadcast Centre Function (CBCF), even if no areas were successfully cancelled.