A radio communication system includes: a serving cell (for example, cell A functional unit 120) configured to transmit, to a radio terminal 10, an AG for directly specifying an uplink user data transmission rate and an RG for relatively specifying the uplink user data transmission rate; and a non-serving cell (for example, cell B functional unit 130) configured to transmit the RG to the radio terminal without transmitting the AG. The non-serving cell includes an instruction unit 132 configured to instruct the serving cell to decrease the uplink user data transmission rate, when a reception power of uplink user data received from the radio terminal 10 exceeds a predetermined interference threshold.