Hard handoff from a wireless local area network to a cellular telephone network
First Claim
1. In a multi-mode portable user terminal (UT), a method for supporting a hard handoff procedure for a call from a wireless local area network (WLAN) to a cellular telephone network, the method comprising:
- establishing a link between a UT and a serving WLAN;
establishing a call via the established WLAN link;
simultaneously monitoring a serving cellular telephone network;
forwarding information identifying the UT within the cellular network, to the serving WLAN;
in response to losing the link with the serving WLAN, performing a hard handoff to the cellular network; and
continuing the call via the cellular network.
1 Assignment
0 Petitions
Accused Products
Abstract
A system and a method are provided for supporting a hard handoff procedure for a call from a wireless local area network (WLAN) to a cellular telephone network. The method includes: establishing a link between a user terminal (UT) and a serving WLAN, and a call via the WLAN link; simultaneously monitoring a serving cellular telephone network; forwarding information identifying the UT within the cellular network, to the serving WLAN; in response to losing the link with the serving WLAN, performing a hard handoff to the cellular network; and, continuing the call via the cellular network. Generally, the hard handoff can be performed if the WLAN is able to communicate the UT'"'"'s identity to the cellular telephone, as the UT'"'"'s position can be determined by the cellular network. The hard handoff is performed with the UT receiving resource allocations in a common control channel message, such as a Short Message Ser vice (SMS) or paging message.
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Citations
23 Claims
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1. In a multi-mode portable user terminal (UT), a method for supporting a hard handoff procedure for a call from a wireless local area network (WLAN) to a cellular telephone network, the method comprising:
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establishing a link between a UT and a serving WLAN;
establishing a call via the established WLAN link;
simultaneously monitoring a serving cellular telephone network;
forwarding information identifying the UT within the cellular network, to the serving WLAN;
in response to losing the link with the serving WLAN, performing a hard handoff to the cellular network; and
continuing the call via the cellular network. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A multi-mode portable user terminal (UT) for supporting a hard handoff procedure for a call from a wireless local area network (WLAN) to a cellular telephone network, the UT comprising:
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a WLAN subsystem for establishing a link between the UT and a serving WLAN, establishing a call via the established WLAN link, and forwarding information identifying the UT within the cellular network, to the serving WLAN; and
a cellular subsystem for monitoring a serving cellular telephone network, receiving a hard handoff command, in response to the WLAN subsystem losing the link with the serving WLAN, and continuing the call via the cellular network. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A system that supports a hard handoff procedure for transferring a call from a wireless local area network (WLAN) to a cellular network, the system comprising:
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a user terminal (UT) comprising;
a WLAN subsystem to establish call through a link between the UT and a serving WLAN, and forward information identifying the UT within a cellular network, to the serving WLAN; and
,a cellular subsystem registered in, and monitoring the serving cellular telephone network, and receiving a hard handoff command to continue the call via the cellular network; and
,a cellular server controller (CSC) having an interface with the WLAN to accept a hard handoff trigger for an identified UT and to further a hard handoff command to the UT cellular subsystem in response to the hard handoff trigger.
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22. At least one processor configured to implement a method for supporting a hard handoff procedure for a call from a wireless local area network (WLAN) to a cellular telephone network, the method comprising:
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establishing a link between a UT and a serving WLAN;
establishing a call via the established WLAN link;
simultaneously monitoring a serving cellular telephone network;
forwarding information identifying the UT within the cellular network, to the serving WLAN;
in response to losing the link with the serving WLAN, performing a hard handoff to the cellular network; and
continuing the call via the cellular network.
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23. A computer-readable medium embodying instructions, which when executed by a process implements a method for supporting a hard handoff procedure for a call from a wireless local area network (WLAN) to a cellular telephone network, the method comprising:
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establishing a link between a UT and a serving WLAN;
establishing a call via the established WLAN link;
simultaneously monitoring a serving cellular telephone network;
forwarding information identifying the UT within the cellular network, to the serving WLAN;
in response to losing the link with the serving WLAN, performing a hard handoff to the cellular network; and
continuing the call via the cellular network.
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Specification