Patent ID: 6940848

Claim:
A mobile voice communication method for enabling a mobile host to initiate a voice call with a communication terminal via Internet and cellular networks, said mobile host being connected to said communication terminal through a first mobile switching center of the cellular network, a first gateway at a near end of the Internet, and a second gateway at a far end of the Internet, said method comprising the steps of: comparing, when said mobile host roams from an area controlled by said first mobile switching center to an area controlled by a second mobile switching center, said first gateway that is connected to said first mobile switching center with a third gateway that is connected to said second mobile switching center; and invoking, if said third gateway and said first gateway are different, a call transfer procedure from said third gateway to said first gateway to establish a connection between said second gateway and said third gateway, and release a connection between said first gateway and said second gateway, wherein said call transfer procedure is invoked by said third gateway in a facility message sent to said first gateway, and wherein said call transfer procedure includes the steps of: said first gateway sending said facility message with call transfer initiate invocation to said second gateway; said second gateway sending a setup message with call transfer setup invocation to said third gateway when receiving said facility message; said third gateway returning a connect message with call transfer result to said second gateway; said second gateway issuing a release complete message with call transfer return result to said first gateway; and said first gateway forwarding said release complete message to said third gateway when receiving said release complete message.