Provided are a method and a wireless device for monitoring a control channel in a wireless communication system. The wireless device monitors a first downlink control channel in a common search space of a subframe, and monitors a second downlink control channel in a user equipment-specific search space of the subframe. The first downlink control channel is modulated by a cell-specific reference signal, and the second downlink control channel is modulated by a reference signal that is specific to the wireless device.