Voice over IP mobility in IP/cellular networks interworking
First Claim
1. 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.
1 Assignment
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Accused Products
Abstract
A mobile host is connected to a communication terminal through a first mobile switching center of a cellular network, a first gateway at a near end of the Internet, and a second gateway at a far end of the Internet. When the mobile host roams from an area controlled by the first mobile switching center to an area controlled by a second mobile switching center, a comparison is done between the first gateway connected to the first mobile switching center and a third gateway that is connected to the second mobile switching center. If the third gateway and the first gateway are different, the third gateway invokes a call transfer procedure to the first gateway to establish a connection between the second gateway and the third gateway, and release a connection between the first gateway and the second gateway.
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Citations
9 Claims
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1. 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:
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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. - View Dependent Claims (2, 3, 4, 5)
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6. A mobile voice communication system for enabling a mobile host to initiate a voice call with a communication terminal via Internet and cellular networks, comprising:
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a plurality of mobile switching centers, provided by the cellular network for enabling said mobile host to establish a call connection; and
a plurality of gateways, provided by the Internet for connecting to the mobile switching centers, wherein said mobile host is connected to said communication terminal through a first mobile switching center of the cellular network, a first gateway at near end of the Internet, and a second gateway at a far end of the Internet, and 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, and said first gateway that is connected to said first mobile switching center is different from a third gateway that is connected to said second mobile switching center, said third gateway invokes a call transfer procedure to said first gateway, so as 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 in said call transfer procedure, said first gateway sends said facility message with call transfer initiate invocation to said second gateway;
said second gateway sends a setup message with call transfer setup invocation to said third gateway when receiving said facility message;
said third gateway returns a connect message with call transfer result to said second gateway;
said second gateway issues a release complete message with call transfer return result to said first gateway; and
said first gateway forwards said release complete message to said third gateway when receiving said release complete message. - View Dependent Claims (7, 8, 9)
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Specification