A data communication method in a carrier aggregation system comprising: an eNB communicating data with a specific User Equipment, UE, over component carriers in the carrier aggregation system using a Time Division Duplex, TDD, uplink and downlink sub-frame configuration adopted for a specific component carrier in the carrier aggregation system, wherein the specific UE is a TDD UE incapable of supporting simultaneous uplink data transmission and downlink data transmission over different component carriers in a same sub-frame; and wherein for the specific component carrier, the eNB communicates data with the specific UE over the specific component carrier in the carrier aggregation system using the TDD uplink and downlink sub-frame configuration adopted for the specific component carrier; and for a non-specific component carrier, the eNB communicates data with the specific UE over the non-specific component carrier in the carrier aggregation system using the TDD uplink and downlink sub-frame configuration adopted for the specific component carrier characterized as follows: the eNB judging whether the non-specific component carrier has a same transmission direction as the specific component carrier in the same sub-frame, and if so, then determining the sub-frame as an available sub-frame of the non-specific component carrier; otherwise, determining the sub-frame as an unavailable sub-frame of the non-specific component carrier; the eNB scheduling for the UE an uplink transmission resource corresponding to an uplink available sub-frame and receiving data transmitted from the UE over the scheduled uplink transmission resource; and the eNB transmitting downlink data to the UE in a downlink available sub-frame. an eNB communicating data with a specific User Equipment, UE, over component carriers in the carrier aggregation system using a Time Division Duplex, TDD, uplink and downlink sub-frame configuration adopted for a specific component carrier in the carrier aggregation system, wherein the specific UE is a TDD UE incapable of supporting simultaneous uplink data transmission and downlink data transmission over different component carriers in a same sub-frame; and wherein for the specific component carrier, the eNB communicates data with the specific UE over the specific component carrier in the carrier aggregation system using the TDD uplink and downlink sub-frame configuration adopted for the specific component carrier; and for a non-specific component carrier, the eNB communicates data with the specific UE over the non-specific component carrier in the carrier aggregation system using the TDD uplink and downlink sub-frame configuration adopted for the specific component carrier characterized as follows: the eNB judging whether the non-specific component carrier has a same transmission direction as the specific component carrier in the same sub-frame, and if so, then determining the sub-frame as an available sub-frame of the non-specific component carrier; otherwise, determining the sub-frame as an unavailable sub-frame of the non-specific component carrier; the eNB scheduling for the UE an uplink transmission resource corresponding to an uplink available sub-frame and receiving data transmitted from the UE over the scheduled uplink transmission resource; and the eNB transmitting downlink data to the UE in a downlink available sub-frame. the eNB judging whether the non-specific component carrier has a same transmission direction as the specific component carrier in the same sub-frame, and if so, then determining the sub-frame as an available sub-frame of the non-specific component carrier; otherwise, determining the sub-frame as an unavailable sub-frame of the non-specific component carrier; the eNB scheduling for the UE an uplink transmission resource corresponding to an uplink available sub-frame and receiving data transmitted from the UE over the scheduled uplink transmission resource; and the eNB transmitting downlink data to the UE in a downlink available sub-frame.