Method and system using a conference bridge for handoff of a multi-mode mobile station

• US 7,466,991 B2
• Filed: 05/26/2005
• Issued: 12/16/2008
• Est. Priority Date: 05/26/2005
• Status: Active Grant

• Current Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Delker, Jason R., Everson, John M.
• Primary Examiner(s): Anderson; Matthew D.
• Assistant Examiner(s): Nguyen; Hai V
• Application Number:
  US11/138,180
• Publication Number:
  US 20060270447A1
• Time in Patent Office: 1,300 Days
• Field of Search: 455/552.1
• US Class Current: 455/552.1
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/4038 with floor control
• CPC Class Codes: H04M 3/42246 where the subscriber uses a multi-mode terminal which moves and accesses different networks with at least one network having a wireline access including cordless PBX
• CPC Class Codes: H04M 3/56 Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities video conference systems H04N7/15
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection

Abstract

A multi-mode mobile station includes a first interface for wireless communication with a wireless local area network (WLAN) and a second interface for wireless communication with a wireless wide area network (WWAN). The multi-mode mobile station is associated with a particular conference bridge, through which all calls to and from the multi-mode mobile station are routed. For example, when a call involving the multi-mode mobile is established via the WLAN, the call includes a WLAN call leg that extends from the conference bridge to the multi-mode mobile station via the WLAN. To effect a handoff during the call, a WWAN call leg is established between the multi-mode mobile station and the conference bridge via the WWAN. The conference bridge bridges the WLAN and WWAN call legs. To complete the handoff, the multi-mode mobile station drops the WLAN call leg and continues the call using the WWAN call leg.

Claims

1. A method for effecting a handoff of a multi-mode mobile station from a first wireless network to a second wireless network, said multi-mode mobile station having a first interface for wireless communication with said first wireless network and a second interface for wireless communication with said second wireless network, said method comprising:

receiving a call request that requests establishment of a call between said multi-mode mobile station and an endpoint;

in response to said call request, identifying a conference bridge, from among a plurality of conference bridges, that is associated with said multi-mode mobile station;

establishing a first call leg between said conference bridge and said multi-mode mobile station via said first wireless network;

receiving a handoff request;

in response to said handoff request, establishing a second call leg between said conference bridge and said multi-mode mobile station via said second wireless network, said conference bridge bridging said first and second call legs; and

dropping said first call leg.

2. The method of claim 1, wherein said call request originates from said multi-mode mobile station.

3. The method of claim 1, wherein said call request originates from said endpoint.

4. The method of claim 1, wherein said first wireless network is a wireless local area network (WLAN) and said second wireless network is a wireless wide area network (WWAN).

5. The method of claim 4, wherein said first call leg extends from said conference bridge to said multi-mode mobile station via a packet-switched network and said second call leg extends from said conference bridge to said multi-mode mobile station via said packet-switched network, a media gateway, and a circuit-switched network.

6. The method of claim 1, wherein said first wireless network is a wireless wide area network (WWAN) and said second wireless network is a wireless local area network (WLAN).

7. The method of claim 6, wherein said first call leg extends from said conference bridge to said multi-mode mobile station via a packet-switched network, a media gateway, and a circuit-switched network, and said second call leg extends from said conference bridge to said multi-mode mobile station via a packet-switched network.

8. The method of claim 1, further comprising:

said multi-mode mobile station transmitting said handoff request via said second wireless network.

9. The method of claim 8, wherein said handoff request is a request to originate a call to a predetermined handoff number.

10. A method for communicating with multi-mode mobile stations that can communicate with at least a first wireless network and a second wireless network, said method comprising:

associating each one of a plurality of said multi-mode mobile stations with a particular one of a plurality of conference bridges;

receiving a call request that requests establishment of a call between an endpoint and a given one of said plurality of multi-mode mobile stations;

in response to said call request, identifying a given conference bridge, from among said plurality of conference bridges, that is associated with said given multi-mode mobile station; and

establishing said call through said given conference bridge.

11. The method of claim 10, wherein associating each one of a plurality of said multi-mode mobile stations with a particular one of a plurality of conference bridges comprises:

defining a plurality of conference bridge identifiers, wherein each one of said conference bridge identifiers corresponds to a particular one of said plurality of conference bridges;

assigning to each one said plurality of multi-mode mobile stations a unique conference bridge identifier from among said plurality of conference bridge identifiers; and

storing for each one of said plurality of multi-mode mobile stations an association between a mobile station identifier of said multi-mode mobile station and its conference bridge identifier.

12. The method of claim 11, wherein said call request identifies said given multi-mode mobile station by a given mobile station identifier.

13. The method of claim 12, wherein identifying a given conference bridge, from among said plurality of conference bridges, that is associated with said given multi-mode mobile station comprises:

determining which conference bridge identifier, from among said plurality of conference bridge identifiers, is associated with said given mobile station identifier of said given multi-mode mobile station, to obtain a given conference bridge identifier; and

determining which conference bridge, from among said plurality of conference bridges, corresponds to said given conference bridge identifier.

14. The method of claim 13, wherein establishing said call through said given conference bridge comprises:

establishing a first call leg between said given conference bridge and said given multi-mode mobile station via said first wireless network.

15. The method of claim 14, further comprising:

receiving a handoff request that includes said given mobile station identifier of said given multi-mode mobile station.

16. The method of claim 15, further comprising, in response to said handoff request:

identifying said given conference bridge identifier from said given mobile station identifier;

identifying said given conference bridge from said given conference bridge identifier; and

establishing a second call leg between said given conference bridge and said given multi-mode mobile station via said second wireless network, said given conference bridge bridging said first and second call legs.

17. The method of claim 14, further comprising:

said given multi-mode mobile station detecting that said first call leg has been dropped and responsively transmitting a call re-establishment request that includes said given mobile station identifier of said given multi-mode mobile station;

identifying said given conference bridge identifier from said given mobile station identifier;

identifying said given conference bridge from said given conference bridge identifier; and

re-establishing said first call leg between said given conference bridge and said given multi-mode mobile station via either of said first and second wireless networks.

18. A system for providing wireless telecommunications for a plurality of multi-mode mobile stations, comprising:

a first wireless network;

second wireless network;

a plurality of conference bridges communicatively coupled to said first and second wireless networks;

a database that associates each one of said plurality of multi-mode mobile stations with a particular one of said plurality of conference bridges; and

a call control system communicatively coupled to said database and to said plurality of conference bridges, wherein said call control system selectively routes calls to and from said multi-mode mobile stations through their associated conference bridges.

19. The system of claim 18, wherein said plurality of conference bridges is provided by at least one media server.

20. The system of claim 19, wherein said at least one media server is communicatively coupled to said first wireless network via a packet-switched network and is communicatively coupled to said second wireless network via said packet-switched network, a media gateway, and a circuit-switched network.