Patent ID: 8014773

Claim:
A mobile communication system in which an asynchronous mobile communication system coexist with a synchronous mobile communication system, the asynchronous mobile communication system including a node B, a radio network controller (RNC) and an asynchronous Mobile Switching Center (MSC), and the synchronous mobile communication system including a Base Transceiver Station (BTS), a Base Station Controller (BSC) and a synchronous MSC, the mobile communication system enabling handover of a Dual Band Dual Mode (DBDM) mobile communication terminal and capable of communicating with the asynchronous and synchronous mobile communication systems, during voice communication, reception alerting, or waiting for a response after origination of a call, wherein: the asynchronous and synchronous MSCs are connected to each other via an Interworking Interoperability Function (IIF), and are connected to a Dual stack Home Location Register (D-HLR); the D-HLR configured to store and manage asynchronous subscription information and synchronous subscription information of the mobile communication terminal; and the IIF configured to store and manage synchronous mobile communication system information, receive the synchronous subscription information of the mobile communication terminal from the D-HLR at a request of the asynchronous MSC for handover, transmit the synchronous mobile communication system information and the synchronous subscription information of the mobile communication terminal to the synchronous MSC and receive a response from the synchronous MSC, thereby setting up a relay line between the asynchronous MSC and the synchronous MSC, and request the asynchronous MSC to release a wireless connection when the mobile communication terminal and the synchronous mobile communication system are connected to each other and notification of completion of the handover is provided by the synchronous MSC.