Patent ID: 8892141

Claim:
A base station comprising: a first determiner configured to determine whether user data has been received from a radio communication terminal by the base station; a second determiner configured to determine whether information from which it may be determined that the user data has been received from the radio communication terminal by another base station has been received from the other base station; a transmitter configured to transmit to the radio communication terminal information indicating whether at least one of the base station and the other base station has received the user data based on at least one of the result of the determination of the first determiner and the result of the determination of the second determiner; an information requester configured to transmit to the other base station a request for information; an information receiver configured to receive the information requested by the information requester; a user data requester configured to transmit to the other base station a request for transmission of the user data; and a user data receiver configured to receive the user data requested by the user data requester, wherein the information requester is further configured to transmit the request for information from which it may be determined whether the user data has been received from the radio communication terminal by the other base station in case the first determiner determines that the user data has not been received from the radio communication terminal by the base station.