Abstract: A method and apparatus of an AMF controller in a wireless communication system are provided. The method and apparatus include: registering a first SIM based on a first registration request message and registering a second SIM based on a second registration request message which has a GUTI for the first SIM. Further, the method and apparatus include: receiving at least one of downlink data and signaling information for the second SIM when a N1 NAS is in CM-Connected state for the first SIM, and transmitting a NAS message indicating at least one of the downlink data and the signaling information for the second SIM over the N1 NAS connection of the first SIM.

Abstract: An apparatus and method for scanning Radio Access Technology (RAT) of a User Equipment (UE) registered in a first cell in a cellular communication network is provided. The method includes performing a Non-Access Stratum (NAS) procedure for establishing a call, disabling, if the NAS procedure fails, capability of the UE to connect to the first cell, checking information relating to neighboring cells in the network, and selecting at least one RAT included in the information relating to the neighboring cells, and scanning a second cell operating in the at least one RAT based on the information relating to the neighboring cells.