Patent ID: 8805378

Claim:
An operating method of a base station of a first communication system for a handover between the first communication system and a second communication system, the method comprising: receiving, by the base station, measured signal level of a downlink, from a terminal; determining, by the base station, a handover initiation to the second communication system, based on the measured signal level of the downlink; transmitting, by the base station, a handover request message to the second communication system via a core network; receiving, by the base station, a message including a radio channel parameter that is required when the terminal accesses the second communication system, from the second communication system via the core network; and forwarding, by the base station, the message, including the radio channel parameter of the second communication system, to the terminal, wherein the handover between the first communication system and the second communication system comprises an inter Radio Access Technologies (RAT) handover.