ETWS, CMAS

ETWS: Earthquake and Tsunami Warning System 地震和海啸预警系统

ETWS is a public warning system with the purpose to broadcast emergency information to all the users in a specific area in a situation like Earthquake or Tsunami. This help to broadcast emergency situation by a local or national authorities to users as quickly as possible.

There are two types of notifications the ETWS that is primary and secondary notifications.

The Primary Notification contains only simple patterned type of disaster information, such as “Earthquake”, or “Tsunami”, or “Tsunami + Earthquake,” etc. When a mobile user receives a Primary Notification, it produces a pre-set alert sound and displays pre-determined text on the screen according to the message content to notify users of the danger.

The Secondary Notification contains detail textual information like the epicentre, seismic intensity and other such information related to danger.

ETWS primary notification is carried by SIB10 and ETWS secondary notifications carried by SIB11.

CMAS: Commercial Mobile Alert System 商用移动预警系统

CMAS notifications carry high emerygency situations.

It is carry by SIB12.

There is an IE in paging message which indicate the presence of CMAS. When decode paging message came to know about CMAS notification and start to receive and decode SIB12 immediately after reading SIB1.

There are three types of alerts through CMAS:

1. Alerts issued by the President or higher authority of geographical area.

2. Alerts involving imminent threats to safety of life, issued in two different categories: extreme threats and severe threats.

3. AMBER Alert or a Child Abduction Emergency. 

“AMBER”是“America's Missing: Broadcasting Emergency Response”（直译为：美国失踪人口：广播紧急回应）的缩写，也是以一名于1996年在美国德州阿灵顿被绑架并杀害的九岁女童安珀·海格曼（Amber Hagerman）命名。在佐治亚州则称为“Levi's Call”，在某些州也以在当地失踪的儿童命名的。

The paging message is used to inform both ETWS and CMAS notifications to UEs in RRC_IDLE and RRC_CONNECTED mode.

WEA: Wireless Emergency Alerts 无线紧急警报，前身是CMAS.