One aspect of the present invention relates to a base station wherein either resource blocks resulting from division of a system bandwidth into blocks of consecutive frequency subcarriers or distributed type resource blocks consisting of frequency subcarriers discretely distributed within the system bandwidth and resulting from segmentation of the resource blocks into multiple resource blocks are assigned to mobile stations, the base station including: a scheduling unit configured to assign either the resource blocks or the distributed type resource blocks to the mobile stations at a predefined assignment cycle based on respective downlink reception channel states transmitted from the mobile stations.