The present disclosure relates to component carrier (CC) selection in a wireless communication system. A user equipment (UE) that is in idle mode may receive a reference signal (RS) from an evolved Node B (eNB), obtain signal quality measurements with respect to the RS, and switch to a new CC based on the signal quality measurements. For a UE that is in connected mode, an eNB may obtain uplink channel condition information corresponding to uplink CCs, obtain downlink channel condition information corresponding to downlink CCs, and select a CC pair for the UE to use based on the uplink channel condition information and the downlink channel condition information.