A resource determination unit determines at least a part within any downlink subframe as a first resource and determines at least a part of an UpPTS (Uplink Pilot Timeslot) or a part of an uplink subframe as a second resource for transmitting an SRS (Sounding Reference Signal). A transmission path state estimation unit estimates a state of a transmission path to a wireless terminal based on a DRS (Demodulation Reference Signal) included in uplink user data after the first resource is determined and until it receives an SRS, and it estimates a state of the transmission path to the wireless terminal based on an SRS after it received the SRS.