Abstract: Provided is a method for performing a cell search operation that includes: determining whether a User Equipment (UE) is camped on a first Radio Access Technology (RAT) among a plurality of RATs and supports camping on a second RAT; acquiring first information corresponding to a first Public Land Mobile Network Identity (PLMN ID) associated with the first RAT and at least one first inter-RAT (IRAT) frequency, the at least one first IRAT frequency being associated with the first RAT; storing the first information corresponding to the first PLMN ID in a database of the UE; detecting an occurrence of one or more first events indicating that the UE is required to leave the first RAT and camp on another RAT to handle the event; performing the cell search operation corresponding to the first PLMN ID based on the stored first information to camp the UE on the second RAT.