Multiple reference signal transmission bandwidths are defined for system frequency bands and hierarchical reference signal bandwidths are defined for each reference signal transmission bandwidth such that a reference signal bandwidth lower than a highest-order reference signal bandwidth is a division of a higher-order reference signal bandwidth. A base station stores reference signal bandwidth information indicating the hierarchical reference signal bandwidths for each system frequency band; broadcasts the reference signal bandwidth information corresponding to a reference signal transmission bandwidth used by the base station; sets a frequency hopping bandwidth for a reference signal; reports, to a user device, the frequency hopping bandwidth and a reference signal bandwidth as assigned reference signal transmission bandwidth information; sets a reference signal transmission frequency band within the frequency hopping bandwidth based on the reference signal bandwidth information and the assigned reference signal transmission bandwidth information; and receives the reference signal from the user device.