MOBILE COMMUNICATION SYSTEM, RADIO BASE STATION AND MOBILE STATION

摘要

An appropriate action is taken when an abnormality in a layer 2 is detected, even in an "Inter-site CA" operation in which communication for a C-plane signal is performed in a cell #1 under a radio base station eNB#1 via a SRB, and communication for a U-plane signal is performed in a cell #11/#12 under a radio base station eNB#11/#12 via a DRB. In a mobile communication system according to the present invention, the radio base station eNB#11/#12 is configured to provide the radio base station eNB#1 with predetermined notification, when an abnormality is detected in a layer 2 of a downlink to a mobile station UE.