Handoff of dual mode mobile device between an IP network and a PLMN
First Claim
1. A mobile device having both internet telephone and cellular telephone operating modes, the device comprising a handoff application that detects a handoff condition for handoff of a first call between a second device and an internet subscription of the mobile device to a cellular subscription of the mobile device and in response thereto initiates a second call from the internet subscription to the cellular subscription of the mobile device through a telephone gateway, initiates transfer of the first call from the internet subscription to the cellular subscription, obtains from the telephone gateway a call leg identifier of the transferred call and stores the call leg identifier in the mobile device.
1 Assignment
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Accused Products
Abstract
A device and a method for handoff of a VoIP internet telephone call from an IP network to a cellular network and for hand-back of the call to the IP network, in which during or after hand-off of the call an identifier of the hand-off call is obtained and stored and the identifier is used during hand-back of the call to the IP network.
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Citations
26 Claims
- 1. A mobile device having both internet telephone and cellular telephone operating modes, the device comprising a handoff application that detects a handoff condition for handoff of a first call between a second device and an internet subscription of the mobile device to a cellular subscription of the mobile device and in response thereto initiates a second call from the internet subscription to the cellular subscription of the mobile device through a telephone gateway, initiates transfer of the first call from the internet subscription to the cellular subscription, obtains from the telephone gateway a call leg identifier of the transferred call and stores the call leg identifier in the mobile device.
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10. A method of handing off a call on a dual band mobile device between an IP network and a cellular network, the method comprising:
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detecting a handoff condition for handoff of a first call between a second device and an internet subscription of a mobile device to a cellular subscription of the mobile device, initiating a second call to the cellular subscription of the mobile device through a telephone gateway, initiating transfer of the first call to the cellular subscription, obtaining from the telephone gateway a call leg identifier of the transferred call, storing the call leg identifier in the mobile device. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A telephone system for handoff of an internet telephone call to a cellular network and which permits hand back of the call from the cellular network, the system comprising:
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a telephone gateway having a subscription service for reporting a call leg identifier of a call handled by the gateway, and a handoff application for storage and operation on a mobile device having both internet telephone and cellular telephone operating modes, the handoff application, when operated on said mobile device, detects a handoff condition for handoff of a first call between a second device and an internet subscription of the mobile device to a cellular subscription of the mobile device and in response thereto initiates a second call from the internet subscription to the cellular subscription of the mobile device through a telephone gateway, initiates transfer of the first call from the internet subscription to the cellular subscription, obtains from the telephone gateway a call leg identifier of the transferred call and stores the call leg identifier in the mobile device. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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26. A mobile device having both internet telephone and cellular telephone operating modes, the device comprising a handoff application which in use during or after hand-off of a telephone call from an IP network to a cellular network obtains and stores an identifier of the hand-off call for uses during future hand-back of the call to an IP network.
Specification