Which of the following events is used by the gNodeB to trigger a blind redirection...

According to the Blind handover or blind redirection method and system, A3 is the event that is used by the gNodeB to trigger a blind redirection procedure. A3 is defined as “neighbour becomes offset better than serving” in 3GPP TS 38.331. When the gNodeB detects that the UE’s signal quality on a neighbouring cell is better than that on the serving cell by a certain offset, it can initiate a blind redirection procedure to switch the UE to the neighbouring cell without requiring measurement reports from the UE.