A wireless communication system comprising: a first base station that provides a first cell; and a second base station that provides a second cell which contains the first cell provided by the first base station or overlaps the first cell, wherein the first base station is configured to: estimate a first radio-wave interference in an uplink direction by measuring, during a period during which transmissions from all mobile terminals connected to the first base station are ceased, a power of an uplink transmission that the first base station receives from a group of mobile terminals (103, 104, 105) which wirelessly communicate with another base station or a plurality of other base stations; and when the first radio-wave interference is equal to or larger than a predetermined first threshold, increase a transmission power so as to extend the radius of the first cell; and the second base station is configured to instruct, out of the group of mobile terminals (103, 104, 105), one mobile terminal (104, 105) or a plurality of mobile terminals (104, 105) that exist in the extended first cell and that are connected to the second base station to be disconnected from the second base station and to be connected to the first base station. a first base station that provides a first cell; and a second base station that provides a second cell which contains the first cell provided by the first base station or overlaps the first cell, wherein the first base station is configured to: estimate a first radio-wave interference in an uplink direction by measuring, during a period during which transmissions from all mobile terminals connected to the first base station are ceased, a power of an uplink transmission that the first base station receives from a group of mobile terminals (103, 104, 105) which wirelessly communicate with another base station or a plurality of other base stations; and when the first radio-wave interference is equal to or larger than a predetermined first threshold, increase a transmission power so as to extend the radius of the first cell; and the second base station is configured to instruct, out of the group of mobile terminals (103, 104, 105), one mobile terminal (104, 105) or a plurality of mobile terminals (104, 105) that exist in the extended first cell and that are connected to the second base station to be disconnected from the second base station and to be connected to the first base station. estimate a first radio-wave interference in an uplink direction by measuring, during a period during which transmissions from all mobile terminals connected to the first base station are ceased, a power of an uplink transmission that the first base station receives from a group of mobile terminals (103, 104, 105) which wirelessly communicate with another base station or a plurality of other base stations; and when the first radio-wave interference is equal to or larger than a predetermined first threshold, increase a transmission power so as to extend the radius of the first cell; and the second base station is configured to instruct, out of the group of mobile terminals (103, 104, 105), one mobile terminal (104, 105) or a plurality of mobile terminals (104, 105) that exist in the extended first cell and that are connected to the second base station to be disconnected from the second base station and to be connected to the first base station.