Patent ID: 8260291

Claim:
A method of performing a periodic public land mobile network (PLMN) search for a mobile station in a CELL_PCH state of radio resource control (RRC) connected mode in a universal mobile telecommunications system (UMTS), the method comprising: providing a mobile station operating in the CELL_PCH state camping on a serving cell of a PLMN utilizing a first PLMN identity; performing a periodic PLMN search with the mobile station and selecting a cell with a second PLMN identity, the second PLMN identity having a higher network priority than the first PLMN identity; performing a CELL UPDATE procedure to register the mobile station with the selected cell utilizing the second PLMN identity only if the serving cell has at least one PLMN identity that is equal common to a PLMN identity of the selected cell, and if the selected cell is in a neighboring cell list of the serving cell, wherein at least one of the serving cell and the selected cell has multiple PLMN identities; the mobile station entering idle mode from the CELL PCH state if the serving cell and the selected cell are not associated with the common PLMN identity; and establishing an RRC connection through the selected cell.