Patent ID: 8923816

Claim:
A method for providing a voice call service for a cellular network seamlessly through a Wireless Local Area Network (WLAN), the WLAN including a WLAN Access Point (AP) and a gateway, to a User Equipment (UE) having a Frame Route Switch (FRS) and a Radio Control Agent (RCA), the method comprising: performing a cellular network resource assignment by the RCA of the UE after receiving a radio resource request message from the FRS of the UE; transmitting, via a gateway of the WLAN to which the RCA is connected, an initial Direct Transfer (DT)-Connection Management (CM) service request from the FRS to a Mobile Switching Center/General Packet Radio Service (GPRS) Support Node (MSC/GSN), in order to request call setup with the cellular network; executing an authentication and security procedure between the FRS and the MSC/GSN via the gateway of the WLAN; provisioning a voice trunk, by the MSC/GSN, for a voice call from the UE using the cellular network; transmitting, from the MSC/GSN to the gateway of the WLAN, a radio bearer assignment request message for requesting the gateway to open a voice trunk between the gateway and the MSC/GSN; transmitting, from the gateway to the RCA, the radio bearer assignment request message to the RCA in order to switch a connection between the RCA and the gateway from a signaling mode to a voice mode; transmitting, from the RCA to the FRS, a radio bearer setup message, upon receiving the radio bearer assignment request message from the gateway; transmitting, from the FRS to the RCA, a radio bearer setup complete message; and transmitting, from the RCA to the MSC/GSN via the gateway, a DT radio bearer assignment complete message in order to complete the voice call setup signaling and to establish the voice call connection.