Patent ID: 8085742

Claim:
A method for use by a mobile communication device in facilitating voice calls through a selected one of a wireless local area network (WLAN) or a wireless wide area network (WWAN), the mobile communication device having a WWAN identification number for receiving voice calls in the WWAN and a WLAN identification number for receiving voice calls in the WLAN, the method comprising the acts of: performing communication operations in the WLAN; for switching the communication operations of the mobile communication device from the WLAN to the WWAN: identifying whether an abrupt WLAN coverage loss occurs such that the mobile communication device fails to communicate via the WLAN a message for forwarding voice calls to the WWAN identification number; if the mobile communication device does not undergo said abrupt WLAN coverage loss, then communicating via the WLAN a message for forwarding voice calls to the WWAN identification number, so that voice calls made to the WLAN identification number are forwarded to the WWAN identification number of the mobile communication device operating in the WWAN; and otherwise, if the abrupt WLAN coverage loss is identified such that the mobile communication device fails to communicate via the WLAN a message for forwarding voice calls to the WWAN identification number, then communicating via the WWAN the message for forwarding voice calls to the WWAN identification number so that voice calls made to the WLAN identification number are forwarded to the WWAN identification number of the mobile communication device operating in the WWAN.