In an aspect, a method of communication performed by a user equipment (UE) camping on a long term evolution (LTE) cell in a wireless communication system is provided. The method include: receiving a Circuit Switched fallback (CSFB) control message from a network, the CSFB control message comprising prioritization information for CS service; determining whether the CS service is triggered; if it is determined that the CS service is triggered, applying a priority to frequencies of at least one cell in accordance with the priority information; performing a mobility procedure based on the applied priority; performing a Radio Resource Control (RRC) connection establishment procedure with a selected inter-RAT cell; and initiating the CS service.