PCU support for sending ETWS primary notifications
ETWS (Earthquake and Tsunami Warning System) doesn't only use SMSCB, but also contains parts that ensure notification of all MS as quickly as possible. Specifically, this means
- there's a PACKET APPLICATION INFO message sent over PACCH to all MS with TBF established
This ticket is about implementing the required features in the PCU.We need to
- receive the ETWS primary notification message from the BTS via the PCU interface
- construct the PACKET APPLICATION INFO message from it
- send it via PACCH to all MS in packet dedicated mode
One interesting question is that the specs don't appear to describe how often this is to be re-transmitted (if at all). I suppose as we're not operating RLC/MAC in reliable mode, messages might get lost and they have to be re-transmitted? For how long? Do we also need to send it to MS who are establishing TBF at some later point? For how long?