An operating method, a base station, and terminal of a cell of a first communication system for a handover between the first communication system and a second communication system are provided. The method includes, receiving, by the base station, a measurement report including measured signal quality, from a terminal, determining, by the base station, a handover initiation to a target radio access network, based on the measured signal quality, transmitting, by the base station, a handover request message to the target radio access network via a core network, receiving, by the base station, radio-related information that is required if the terminal accesses the target radio access network, from the target radio access network via the core network, and transmitting, by the base station, the radio-related information of the target radio access network, to the terminal, wherein the handover between the source radio access network and the target radio access network comprises an inter radio access technology (RAT) handover.