Patent ID: 8090401

Claim:
A method of handing off a call at a dual-mode subscriber device from a wireless local area network to a wireless communication system comprising: creating, at a virtual gateway, a message in a first control signaling format initiating a call from an IP-based telephone switch to the dual-mode subscriber device via the wireless communication system; receiving, at the dual-mode subscriber device, the call from the wireless communication system; switching, at the dual-mode subscriber device, the call from the wireless local area network to the connection to the wireless communication system; performing, at the dual-mode subscriber device, at least one of (1) transmitting a WLAN-based handoff instruction to the virtual gateway and (2) receiving a WLAN-based handoff instruction from the virtual gateway; creating and sending, at the virtual gateway, a registration message to the IP-based telephone switch; and receiving, at the dual-mode subscriber device, a call confirmation message from the virtual gateway via the wireless local area network, wherein the call confirmation message originated at the IP-based telephone switch.