Method and system using a media gateway for handoff of a multi-mode mobile station

• US 8,010,112 B1
• Filed: 04/28/2005
• Issued: 08/30/2011
• Est. Priority Date: 04/28/2005
• Status: Active Grant

• Current Assignee: Sprint Spectrum LLC (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Delker, Jason R., Everson, John M.
• Primary Examiner(s): SAMS, MATTHEW C
• Application Number:
  US11/117,681
• Time in Patent Office: 2,315 Days
• Field of Search: 455436-444, 4555521-5531, 455/456.3, 455/414.1, 455/418, 455/566, 455/527, 455/419, 455/416, 455/413
• US Class Current: 455/437
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04W 36/0022 for transferring data sessions between adjacent core network technologies
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 36/36 by user or terminal equipment
• CPC Class Codes: H04W 88/16 Gateway arrangements

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). A call control system routes all calls to and from the multi-mode mobile station through a media gateway that serves as an anchor point for handoffs between the WLAN and WWAN. For example, while involved in a call that has a WLAN call leg from the media gateway, the multi-mode mobile transmits a handoff request. The call control system then establishes a WWAN call leg from the media gateway, and the multi-mode mobile station stores in a buffer any media received via the WWAN call leg. The call control system subsequently transmits a handoff instruction to the multi-mode mobile station. In response, the multi-mode mobile station plays out the stored media and drops the WLAN call leg.

Claims

1. A method for call handoff between a first wireless network and a second wireless network for a multi-mode mobile station, said multi-mode mobile station including 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:

while said multi-mode mobile station is engaged in a first communication session with an endpoint via said first interface, said multi-mode mobile station transmitting a handoff request via said first interface;

said multi-mode mobile station receiving media via said second interface after becoming engaged in a second communication session with said endpoint via said second interface;

said multi-mode mobile station storing said media, thereby accumulating stored media;

said multi-mode mobile station receiving a handoff instruction via said first interface; and

in response to said handoff instruction, said multi-mode mobile station conveying said stored media to a user and dropping said first communication session.

2. 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).

3. 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).

4. The method of claim 1, wherein said first communication session is a first call leg of a voice call involving said multi-mode mobile station and said endpoint, and said second communication session is a second call leg of said voice call.

5. The method of claim 1, further comprising:

while said multi-mode mobile station is engaged in said first communication session, said multi-mode station determining that said second wireless network is available and preferred.

6. The method of claim 1, wherein said handoff request requests establishment of said second communication session with said endpoint via said second interface.

7. The method of claim 6, wherein said handoff request is a SIP UPDATE message.

8. The method of claim 7, wherein said handoff instruction is a predetermined response to said SIP UPDATE message.

9. The method of claim 1, further comprising:

said multi-mode mobile station establishing said second communication session with said endpoint via said second interface.

10. The method of claim 9, wherein said multi-mode mobile station establishing said second communication session comprises:

said multi-mode mobile station registering with said second wireless network;

said multi-mode mobile station receiving an incoming call request via said second interface; and

said multi-mode mobile station automatically answering said incoming call request.