An object of the present invention is to reduce the communication delay.
A small base station 120 transmits data to the terminal 101 in the first state. Terminal 101, in the first state, receiving the data transmitted by the small base station 120, and transmits to the macro base station 110 a response signal to the received data. Macro base station 110 in the first state, and transfers the response signal transmitted by the terminal 101 to the small base station 120. At least one of the macro base station 110 and the small base station 120, the transmission delay between the macro base station 110 and the small base station 120, the type of the communication by the data, based on at least one of, from the first state , send a small base station 120 is the data to the terminal 101, terminal 101 performs control for switching to the second state to transmit a response signal to the small base station 120.
.FIELD 1