A method of recognizing states and locations of user equipment in a network by using a random access (RA) channel at a base station without alteration of the conventional network environment or configurations of user equipment. A mobile communication system of an embodiment includes a first base station; and one or more second base stations having service regions smaller than a service region of the first base station. The first base station is operable to broadcast configuration information to the user equipment for connecting to at least one of the one or more second base stations. The user equipment is operable to transmit an uplink signal to at least one of the one or more second base stations in accordance with the configuration information received from the first base station, and at least one of the one or more second base stations is operable to transmit information on the user equipment that transmitted the uplink signal to the first base station after receiving the uplink signal.