A wireless communication system that includes a relay node is disclosed. The relay node supporting carrier aggregation (CA) comprises a first antenna for performing communication with a base station through a backhaul link; a plurality of backhaul link radio frequency (RF) chains connected with the first antenna, for transmitting and receiving a radio signal for backhaul link transmission; a second antenna for performing communication with a user equipment through an access link; a plurality of access link RF units connected with the second antenna, for transmitting and receiving a radio signal for access link transmission; and a control unit controlling the plurality of backhaul link RF chains and the plurality of access link RF chains to share at least a part of RF components between the backhaul link RF chains and the access link RF chains.