In a wireless cellular communication system, one base station controls data transmission and reception for a plurality of user equipments (UEs), and scheduling information on downlink data, for example, time/frequency information for data transmission and MCS (modulation and coding scheme) and HARQ (hybrid automatic retransmission request) related information are transmitted to a corresponding UE to allow the UE to receive data. Similarly, the base station notifies the corresponding UE of uplink scheduling information to allow the UE to transmit uplink data. Recently, CA (carrier aggregation) for transmitting downlink data to a single UE by aggregating unit component carrier (CC) has been considered to support a wider bandwidth while using band identification of the related art. Particularly, in the LTE standard, self-carrier scheduling and cross-carrier scheduling have been considered. In the self-carrier scheduling, each of a plurality of CCs transmits a control channel having scheduling information in a state that a plurality of CCs of different duplex modes or the same duplex mode are aggregated. In the cross-carrier scheduling, one of the plurality of CCs transmits a control channel having scheduling information of another CC. In the current LTE standard, CA for transmitting downlink data by aggregating 5 CCs has been considered. However, CA enhancement for transmitting downlink data by aggregating 5 or more CCs, for example, 8 or 16 CCs is recently considered to support traffic load which is rapidly increased.
USPTO Backgrounds
USPTO Backgrounds