Public Warning System (PWS) in Release-9

Public Warning System (PWS) is generalization of Earthquake and Tsunami Warning System (ETWS). The requirements for PWS has been defined in 3GPP Release 9 in 3GPP TS 22.268. 3GPP TR 22.968 details the Study for requirements for a Public Warning System (PWS) service.

The following list gives the high level general requirements for Warning Notification delivery:

- PWS shall be able to broadcast Warning Notifications to multiple users simultaneously with no acknowledgement required.
- Warning Notifications shall be broadcast to a Notification Area which is based on the geographical information as specified by the Warning Notification Provider.
- PWS capable UEs (PWS-UE) in idle mode shall be capable of receiving broadcasted Warning Notifications.
- PWS shall only be required to broadcast Warning Notifications in languages as prescribed by regulatory requirements.
- Warning Notifications are processed by PWS on a first in, first out basis, subject to regulatory requirements.
- Reception and presentation of Warning Notifications to the user shall not pre-empt an active voice or data session.
- Warning Notifications shall be limited to those emergencies where life or property is at imminent risk, and some responsive action should be taken.



Commercial Mobile Alert System (CMAS) is Public Warning System (PWS) that delivers Warning Notifications provided by Warning Notification Providers to CMAS capable PWS-UEs. CMAS defines three different classes of Warning Notifications (Presidential, Imminent Threat and Child Abduction Emergency). The CMAS functionality does not require modifications to the 3GPP-defined cell broadcast functionality.

3GPP Earthquake and Tsunami Warning service (ETWS)

Earthquake and Tsunami Warning Service: is a service that delivers Earthquake and Tsunami Warning Notifications provided by Warning Notification Providers to the UEs which have the capability of receiving Warning Notifications within Notification Areas through the 3GPP network.

Earthquake and Tsunami Warning System: is a subsystem of Public Warning System that delivers Warning Notifications specific to Earthquake and Tsunami provided by Warning Notification Providers to the UEs which have the capability of receiving Warning Notifications within Notification Areas through the 3GPP network.

Earthquake and Tsunami Warning service is provided to users by PLMN operators. Warning Notification Providers produce Warning Notification to PLMN operator when an event occurs e.g. an Earthquake. PLMN operators distribute Warning Notifications to users by utilizing ETWS.

The ETWS consists of the PLMN that is capable to deliver Warning Notification and the UEs that are capable to receive Warning Notification. A Warning Notification Provider is able to send Warning Notification to the users in Notification Area by activating ETWS. Warning Notification is classified into two types depending on the purpose and urgency of the notification.

The first type of Notification is called Primary Notification. This type of notification delivers the most important information of the threat that is approaching to users (e.g. the imminent occurrence of Earthquake or Tsunami). The notification shall be delivered to the users as soon as possible.

The second type of Notification is called Secondary Notification. This type of notification delivers additional information, such as instructions on what to do / where to get help as long as the emergency lasts.

More Information at 3GPP TS 22.168: Earthquake and Tsunami Warning System (ETWS) requirements; Stage 1.

You may also find interesting this FAQ for Cell Broadcast (CB) in Public Warning.

E-MBMS out of Rel-8, CBS in

E-MBMS is out of Release 8 and CBS (Cell Broadcast Service) is back in LTE. CBS as far as I am aware is not used much anywhere except Japan. CBS has been added specifically as now there is requirement for EWTS (Earthquake and Tsunami Warning System) .