Patent ID: 8094622

Claim:
A mobile communication system comprising: a gateway device; a source base station and a target base station; and user equipment configured to receive packet data of packets sequentially transmitted from the gateway device via either of the source base station and the target base station; wherein at the time of handover processing performed accompanying a movement of the user equipment from the source base station to the target base station, the source base station transfers to the target base station, packet data received from the gateway device, but not yet transmitted to the user equipment, and when transferring the packet data to the target base station, the source base station assigns first transfer start information, which indicates a start of transfer, to a header in a leading packet of the packet data untransmitted to the user equipment, and wherein the gateway device assigns second transfer start information to a header in a leading packet of packet data, which are to be directly transmitted from the gateway device to the target base station, and based on the first and second transfer start information in respective leading packets of the packet data transmitted from the source base station and the gateway device, the target base station recognizes a transmission order of packet data, so as to transmit the packet data received from the source base station and the gateway device in the recognized transmission order to the user equipment.