The method of distributing emergency information to LTE radio networks is shown in Figure 1. When the CBC receives a request for emergency information distribution from CBE, it creates the text to be sent to the terminals and specifies the distribution area from the information in the request message.
Next, the CBC sends a Write-Replace Warning Request message to the MME of the specified area. This message contains information such as disaster type, warning message text, message distribution area, Primary Notification information, etc. When the MME receives this message, it sends a response message to the CBC to notify that the message was correctly received. The CBC then notifies the CBE that the distribution request was received and the processing has begun. At the same time, the MME checks the distribution area information in the received message and, if a TAI list is included, it sends the Write-Replace Warning Request message only to the eNB that belong to the TAI in the list. If the TAI list is not included, the message is sent to all of the eNB to which the MME is connected.
When the eNB receives the Write-Replace Warning Request message from the MME, it determines the message distribution area based on the information included in the Write-Replace Warning Request message and starts the broadcast.