SIB12 in LTE

SIB12: CMAS notification

• contains a CMAS notification
• CMAS notifications carry high emerygency situations and is defined for three catagories:

  -Presiential Alerts (President of a geographical location can send alerts)

  -Threat Alerts (Tornado/Hurricane alerts)

  -AMBER Alerts (Child abduction, endangered situation)

• introduced in Release9

Signalling radio bearer: N/A
RLC-Mode: TMLogical channel: BCCH
Direction: E‑UTRAN to UE

Important contents of SystemInformationBlockType12
messageIdentifier
serialNumber
warningMessageSegmentType
warningMessageSegmentNumber
warningMessageSegment
dataCodingScheme

Field Descriptions:

messageIdentifier	Identifies the source and type of CMAS notification
serialNumber	Identifies variations of a CMAS notification
warningMessageSegmentType	Indicates whether the included CMAS warning message segment is the last segment or not
warningMessageSegmentNumber	Segment number of the CMAS warning message segment contained in the SIB. A segment number of zero corresponds to the first segment, one corresponds to the second segment, and so on
warningMessageSegment	Carries a segment of the Warning Message
dataCodingScheme	Identifies the alphabet/coding and the language applied variations of a CMAS notification