Patent ID: 8724569

Claim:
A radio base station comprising: a resource assignment unit configured to assign resource candidates to a first mobile station for transmitting a semi-persistent scheduling transmission acknowledgement signal, in a semi-persistent scheduling bearer setting process, wherein said resource candidates respectively formed by a combination of a frequency direction resource and a code direction resource that the first mobile station uses for transmitting a transmission acknowledgement signal after a predetermined timing from a timing of receiving downlink data via a downlink data channel scheduled by semi-persistent scheduling, and the resource assignment unit is configured to assign the resource candidates to the first mobile station, based on an assigned number of predetermined resources during a transmission period for transmitting the semi-persistent scheduling transmission acknowledgement signal transmitted from the first mobile station, the predetermined resource being formed by a combination of a frequency direction resource and a code direction resource, and the resource assignment unit is configured to select a resource for transmitting the semi-persistent scheduling transmission acknowledgement signal from among the resource candidates, when the downlink data is scheduled by the semi-persistent scheduling, wherein the assigned number of the predetermined resources is a total number of other mobile stations, to which the predetermined resource has been assigned as resource candidates for transmitting a semi-persistent scheduling transmission acknowledgement signal from the other mobile stations, at each sub-frame of the transmission period for transmitting the semi-persistent scheduling transmission acknowledgement signal from the first mobile station.