A user equipment in a communication environment in which a plural communication systems interwork comprises: a processor for searching a base station of a first communication system, the base station having a signal intensity higher than a threshold; and a receiver for receiving information of a base station list of a second communication system adjacent to the terminal through a first communication system link from the searched base station of the first communication system, wherein the processor turns on a second communication system mode in the case of failing in random access channel (RACH) transmissions a predetermined number of times to the searched base station of the first communication system, wherein the receiver receives a beacon signal including an indicator which indicates support of an uplink transmission of the first communication system from base stations included in the information of the base station list of the second communication system; the processor recognizes that an uplink transmission is disabled or only a downlink transmission is enabled through the first communication system link based on the beacon signal; and the information of the base station list of the second communication system may include an indicator which indicates whether the base station of the second communication system supports a downlink (DL) or uplink (UL) transmission through the first communication system link.