5G System Learning - PWS Restart Indication and Failure Indication

The Public Warning System (PWS) is a communications system operated by government agencies or related organizations for providing public warning information in emergency situations. In 5G (NR) networks, PWS messages are broadcast via 5G (NR) base stations connected to the 5G Core (5GC). The base stations are responsible for scheduling and broadcasting warning messages and using paging to notify user equipment (UE) of the broadcasted warning messages, thereby ensuring rapid dissemination and wide coverage of emergency information. 3GPP defines PWS Restart Indication and PWS Failure Indication in TS 8.413 as follows:

1. The PWS Restart Indication procedure notifies the AMF to reload PWS information for some or all cells of the NG-RAN node from the CBC, if necessary. The Restart Indication procedure uses non-UE-associated signaling; successful operation is shown in Figure 8.9.3.2-1, where:

• The NG-RAN node initiates this procedure by sending a PWS Restart Indication message to the AMF. Upon receipt of the PWS Restart Indication message, the AMF shall proceed as defined in TS 23.527.
• If an emergency area ID is available, the NG-RAN node should also include it in the list of emergency area IDs used for the Restart IE.

2. PWS anomalies primarily occur when PWS notification operations fail (or become invalid) in individual cells within the wireless network. 3GPP defines PWS Failure Indication in TS 38.413 as follows.

The PWS Failure Indication procedure is intended to notify the AMF that an ongoing PWS operation in one or more cells of the NG-RAN node has failed. The procedure is shown in Figure 8.9.4.2-1 below. The PWS Failure Procedure utilizes non-UE-associated signaling.

The NG-RAN node initiates this procedure by sending a PWS Failure Indication message to the AMF. Upon receipt of the PWS Failure Indication message, the AMF should proceed as defined in TS 23.041.