Patent ID: 8238918
Filing Date: 2012-08-07
Classification: H04W

Abstract:
1. A method of performing handover from an asynchronous mobile communication network to a synchronous mobile communication network, in which the asynchronous mobile communication network and the synchronous mobile communication network coexist for a dual-band/dual mode mobile communication terminal, and which includes a dual-stack Home Location Register (HLR) required to manage information about subscribers to the asynchronous and synchronous mobile communication networks, the mobile communication terminal including an asynchronous Radio Frequency (RF) device for performing asynchronous communication with the asynchronous mobile communication network, a synchronous RF device for performing synchronous communication with the synchronous mobile communication network, and a common module for controlling wireless communicating with the synchronous/asynchronous mobile communication networks through the synchronous and asynchronous RF devices, the method comprising: a first step of an access network of the asynchronous mobile communication network requesting handover to a Mobile Switching Center (MSC) of the asynchronous mobile communication network in response to a handover request from the mobile communication terminal; a second step of the MSC of the asynchronous mobile communication network determining whether the requested handover is handover to the synchronous mobile communication network in response to the handover request, requesting subscriber information of the mobile communication terminal from the dual-stack HLR, and receiving the subscriber information from the dual-stack HLR if it is determined that the requested handover is handover to the synchronous mobile communication network; a third step of transmitting a handover request message to the synchronous mobile communication network, based on the subscriber information of the mobile communication terminal received at the second step; a fourth step of an MSC of the synchronous mobile communication network assigning a forward channel to the mobile communication terminal, based on the subscriber information; a fifth step of, if the MSC of the synchronous mobile communication network transmits a response message to the asynchronous mobile communication network after channel assignment has been performed at the fourth step, the asynchronous mobile communication network transmitting a handover instruction message to the asynchronous RF device of the mobile communication terminal; a sixth step of the mobile communication terminal setting up the synchronous RF device in response to the handover instruction message, connecting to the synchronous mobile communication network through assignment of a reverse channel and achievement of synchronization, and transmitting a handover completion message to the synchronous mobile communication network; a seventh step of the synchronous mobile communication network transmitting a handover completion message to the asynchronous mobile communication network in response to the handover completion message at the sixth step; and an eighth step of the MSC of the asynchronous mobile communication network transmitting a path release command to the access network in response to the handover completion message from the synchronous mobile communication network, and receiving a response from the access network, thus releasing a path between the asynchronous mobile communication network and the asynchronous RF device of the mobile communication terminal.