An apparatus for an idle mode terminal is configured to perform a method for operating the idle mode terminal in a Machine to Machine (M2M) communication system. A paging message is received from the base station during a paging listening interval. The Apparatus determines whether an indicator indicating receipt of multicast group data is included in the paging message. When the indicator indicating the receiving of multicast group data is included, data transmitted via a downlink resource that uses an identifier mask of a multicast group to which a terminal belongs is received. Thereafter, a paging non-listening interval is entered.