A technique is provided to control transmitting, by a mobile station (MS) that uses carrier aggregation, a message including an interoperability test (IOT) indication for one or more uplink-downlink (UL-DL) configuration combinations of time-division-duplex (TDD) radio frames for use by a primary cell and a secondary cell. In one example implementation, an IOT indication may be provided for one or more (or each) uplink-downlink configuration combinations (e.g., one IOT indication per UL-DL configuration combination). In another example implementation, an IOT indication may be provided for one or more sets of uplink-downlink configuration combinations, where each set may include a plurality of UL-DL configuration combinations.