Method and apparatus for inter-system active handoff of a hybrid subscriber unit
First Claim
1. A method for inter-network handoff of a voice call from a circuit switched network to a packet switched network, the method comprising:
- conveying forward link voice traffic to, and receiving reverse link voice traffic from, a subscriber unit via the circuit switched network in association with the call;
determining to hand off the call;
receiving, by the packet switched network notification of the need for a handoff;
in response to receiving the handoff notification, conveying, by the packet switched network to the subscriber unit, a request to perform the handoff and establishing a communication session between the packet switched network and the subscriber unit;
receiving reverse link voice traffic from the subscriber unit via the circuit switched network and via the packet switched network;
when receiving reverse link voice traffic via the packet switched network and the circuit switched network, switching from the circuit switched network to the packet switched network for conveyance of the forward link voice traffic to the subscriber unit; and
in response to switching the forward link voice traffic from the circuit switched network to the packet switched network, ceasing reception of reverse link voice traffic via the circuit switched network while continuing to receive reverse link voice traffic via the packet switched network.
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Accused Products
Abstract
A communication system provides for an active handoff of a voice call between a packet switched network and a circuit switched network. An active handoff from the packet switched network to the circuit switched network is accomplished by multicasting the call over forward links of both networks during the handoff. An active handoff from the circuit switched network to the packet switched network is accomplished by multicasting the call over reverse links of both networks during the handoff. The former handoff further may be facilitated by routing the call for each network through a same packet data control switch, and the latter handoff further may be facilitated by routing the call for each network through a same mobile switching center. In order for a subscriber unit to operate concurrently in both networks, the subscriber unit may comprise multiple transceivers or a single transceiver that is rapidly switched between the networks.
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Citations
16 Claims
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1. A method for inter-network handoff of a voice call from a circuit switched network to a packet switched network, the method comprising:
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conveying forward link voice traffic to, and receiving reverse link voice traffic from, a subscriber unit via the circuit switched network in association with the call; determining to hand off the call; receiving, by the packet switched network notification of the need for a handoff; in response to receiving the handoff notification, conveying, by the packet switched network to the subscriber unit, a request to perform the handoff and establishing a communication session between the packet switched network and the subscriber unit; receiving reverse link voice traffic from the subscriber unit via the circuit switched network and via the packet switched network; when receiving reverse link voice traffic via the packet switched network and the circuit switched network, switching from the circuit switched network to the packet switched network for conveyance of the forward link voice traffic to the subscriber unit; and in response to switching the forward link voice traffic from the circuit switched network to the packet switched network, ceasing reception of reverse link voice traffic via the circuit switched network while continuing to receive reverse link voice traffic via the packet switched network. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A communication system that provides for inter-network handoff of a voice call from a circuit switched network to a packet switched network, the system comprising:
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a base station that transmits forward link voice traffic to a subscriber unit via a first forward link, receives reverse link voice traffic from the subscriber unit via a first reverse link in association with the call; a mobile switching center, in communication with the base station, that conveys the forward link voice traffic to the base station and receives the reverse link voice traffic from the base station; a packet data control switch that receives a notification of a handoff of the call and, in response to receiving the handoff notification, requests that the subscriber unit perform the handoff; an access network in communication with the packet data control switch that, in response to the request to perform the handoff, establishes a second forward link and a second reverse link with the subscriber unit; and wherein, in response to the establishment of the second forward link and the second reverse link with the subscriber unit, each of the base station and the access network receives reverse link voice traffic from the subscriber unit and conveyance of the forward link voice traffic to the subscriber unit is switched from the base station and the first forward link to the access network and the second forward link, and wherein, in response to switching said conveyance of the forward link voice traffic from the base station and the first forward link to the access network and the second forward link, the base station ceases receiving the reverse link voice traffic while the access network continues to receive the reverse link voice traffic. - View Dependent Claims (13, 14, 15, 16)
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Specification