A multi-carrier cellular radio communication system includes a serving base station associate with a serving cell currently serving a mobile radio and a non-serving base station within range of the mobile radio and associated with a non-serving cell. The mobile radio can transmit to the serving base station at the same time over multiple radio frequency carriers. An estimate is made of inter-cell interference in the non-serving cell caused by uplink transmission by the mobile radio over one or more of the multiple radio frequency carriers over which the mobile radio is currently simultaneously transmitting. If the estimated inter-cell interference in the non-serving cell exceeds a predetermined threshold, then the inter-cell interference in the non-serving cell is reduced or limited by managing radio resources so that the estimated inter-cell interference in the non-serving cell is or becomes less than the predetermined threshold.