1. A communication system comprising:base stations; and
a communication terminal configured to perform radio communication with the base stations, wherein
the base stations include:
an energy saving base station configuring an energy saving cell configured to switch between a normal operation state and an energy saving state with power consumption lower than that of the normal operation state, and
a compensating base station configuring a compensation cell that compensates for a coverage being a range in which the energy saving cell is capable of communication when the energy saving cell is in the energy saving state,
when the energy saving cell switches between the normal operation state and the energy saving state, at least one cell of the energy saving cell and the compensation cell gradually increases or decreases a downlink transmission power, and
the at least one cell notifies the communication terminal of a magnitude of a transmission power of a downlink reference signal every time the at least one cell increases or decreases the downlink transmission power.