A mobile communication system includes a first Home Node B (HNB); a second HNB; and a HNB gateway (HNB-GW) that is connected to a core network, wherein the first HNB is configured to communicate with a user equipment (UE) before a relocation of intra HNB-GW in which the UE is relocated from the first HNB to the second HNB, wherein the second HNB is configured to communicate with a user equipment (UE) after the relocation and send Iu-UP Initialization comprising an RFCI information to the HNB-GW during the relocation, and wherein the HNB-GW is configured to receive the Iu-UP Initialization.