A wireless communication system comprising: a first base station configured to communicate using a frequency within a licensed band; a plurality of second base stations (2, 5) configured to communicate using a frequency within an unlicensed band; and a communication terminal configured to simultaneously communicate with the first base station and any of the plurality of second base stations (2, 5), wherein the communication terminal is further configured to detect first identification information broadcasted from the first base station, the first identification information indicating a first communication network to which the first base station belongs, generate a measurement report including a measurement result regarding one or more of the plurality of second base stations (2, 5), transmit the measurement report to the first base station, detect second identification information broadcasted from a third base station selected by the first base station in accordance with the measurement report and being any of the plurality of second base stations (2, 5), the second identification information indicating a second communication network to which the second base stations (2, 5) belong, and establish a connection with the third base station when the second identification information coincides with the first identification information. a first base station configured to communicate using a frequency within a licensed band; a plurality of second base stations (2, 5) configured to communicate using a frequency within an unlicensed band; and a communication terminal configured to simultaneously communicate with the first base station and any of the plurality of second base stations (2, 5), wherein the communication terminal is further configured to detect first identification information broadcasted from the first base station, the first identification information indicating a first communication network to which the first base station belongs, generate a measurement report including a measurement result regarding one or more of the plurality of second base stations (2, 5), transmit the measurement report to the first base station, detect second identification information broadcasted from a third base station selected by the first base station in accordance with the measurement report and being any of the plurality of second base stations (2, 5), the second identification information indicating a second communication network to which the second base stations (2, 5) belong, and establish a connection with the third base station when the second identification information coincides with the first identification information. detect first identification information broadcasted from the first base station, the first identification information indicating a first communication network to which the first base station belongs, generate a measurement report including a measurement result regarding one or more of the plurality of second base stations (2, 5), transmit the measurement report to the first base station, detect second identification information broadcasted from a third base station selected by the first base station in accordance with the measurement report and being any of the plurality of second base stations (2, 5), the second identification information indicating a second communication network to which the second base stations (2, 5) belong, and establish a connection with the third base station when the second identification information coincides with the first identification information.