Patent ID: 8849245

Claim:
A mobile communication method, comprising: a step of setting a radio bearer between a radio base station and a relay node in an attach process of the relay node; a step of notifying the relay node, by the radio base station, of information to designate a data radio bearer for each radio bearer of a plurality of radio bearers to be set and a flag indicating whether it is necessary for the data radio bearer to perform integrity protection, by using an information element settable within “RRC Connection Reconfiguration”; a step of generating, by the relay node, a key for integrity protection, for the data radio bearer for which it is necessary to perform integrity protection, with reference to the flag notified by the “RRC Connection Reconfiguration”; and a step of generating, by the radio base station, a key for performing integrity protection for the data radio bearer for which it is necessary to perform integrity protection, in a security mode command process performed in an attach process of the relay node.