Method and apparatus for link layer assisted handoff

• US 20060245394A1
• Filed: 02/13/2006
• Published: 11/02/2006
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Natarajan, Kadathur S., Ali, Mohammed D., Baba, Kamel A.
• Granted Patent: US 7,623,493 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/0016 Hand-off preparation specially adapted for end-to-end data sessions
• CPC Class Codes: H04W 36/0019 adapted for mobile IP [MIP]
• CPC Class Codes: H04W 76/20 Manipulation of established connections
• CPC Class Codes: H04W 80/02 Data link layer protocols
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 80/12 Application layer protocols, e.g. WAP [Wireless Application Protocol]

Abstract

Various embodiments are described to address the need for an apparatus and method that improves upon known handoff techniques, such as Mobile IP and Fast Mobile IP, to improve the mobility experience of an end user. OSI layer 2-originated indications of a handoff being imminent (301, 501, 502), a link down for handoff (307, 509, 510), and a new link up after handoff (309, 511, 512) are introduced. These indications can be used by applications (such as real-time/streaming applications on the mobile (101)) to take suitable proactive measures prior to an actual handoff. Examples of such measures include the buffering of data to be used during the handoff interval in a way that improves the seamless mobility experience of the end user.

Claims

1. A method for link layer assisted handoff comprising:

indicating by layer 2 (L2) of an Open Systems Interconnection (OSI)-based communications interface that a handoff from a serving OSI-based communications interface to a target OSI-based communications interface is imminent, wherein L2 of the OSI-based communications interface indicates to an application operating at an OSI layer above OSI layer 3 that the handoff is imminent;

subsequent to indicating that the handoff is imminent, indicating to the application by L2 of the OSI-based communications interface that a link to the serving OSI-based communications interface is down for the handoff to the target OSI-based communications interface.

2. The method of claim 1, further comprising

receiving, from an access network (AN), an OSI layer 2 (L2)-originated indication that the handoff to a target OSI-based communications interface is imminent for the MN.

3. The method of claim 1, further comprising

receiving, from an access network (AN), an OSI layer 2 (L2)-originated indication that the link to the serving OSI-based communications interface is down for the handoff to the target OSI-based communications interface.

4. The method of claim 1, further comprising

providing to the application, subsequent to indicating that the link to the serving OSI-based communications interface is down for the handoff, an OSI layer 2 (L2)-originated indication that a link to the target OSI-based communications interface is up.

5. The method of claim 4, further comprising

receiving, from an access network (AN), an OSI layer 2 (L2)-originated indication that the link to the target OSI-based communications interface is up.

6. The method of claim 1, further comprising

requesting that additional data for use during handoff be sent to the MN prior to handoff, wherein the request is directed to an access network (AN) and is in response to the OSI layer 2 (L2)-originated indication that the handoff to a target OSI-based communications interface is imminent.

7. The method of claim 1, further comprising

receiving, prior to handoff from an access network (AN), additional data for use during handoff.

8. A mobile node (MN) comprising:

a transceiver;

a processing unit, communicatively coupled to the transceiver,

adapted to provide an Open Systems Interconnection (OSI)-based communications interface for use by an application, operating at an OSI layer above OSI layer 3, to communicate via the transceiver;

adapted to provide to the application an OSI layer 2 (L2)-originated indication that a handoff to a target OSI-based communications interface is imminent;

adapted to provide to the application, subsequent to indicating that the handoff is imminent, an OSI layer 2 (L2)-originated indication that a link to a serving OSI-based communications interface is down for the handoff to the target OSI-based communications interface.

9. The MN of claim 8, wherein the processing unit is further adapted to receive, from an access network (AN) via the transceiver, an OSI layer 2 (L2)-originated indication that the handoff to a target OSI-based communications interface is imminent for the MN.

10. The MN of claim 8, wherein the processing unit is further adapted to receive, from an access network (AN) via the transceiver, an OSI layer 2 (L2)-originated indication that the link to the serving OSI-based communications interface is down for the handoff to the target OSI-based communications interface.

11. The MN of claim 8, wherein the processing unit is further adapted to provide to the application, subsequent to indicating that the link to the serving OSI-based communications interface is down for the handoff, an OSI layer 2 (L2)-originated indication that a link to the target OSI-based communications interface is up.

12. The MN of claim 11, wherein the processing unit is further adapted to receive, from an access network (AN) via the transceiver, an OSI layer 2 (L2)-originated indication that the link to the target OSI-based communications interface is up.

13. The MN of claim 8, wherein the processing unit is further adapted to request that additional data for use during handoff be sent to the MN prior to handoff, wherein the processing unit request is directed to an access network (AN) via the transceiver and is in response to the OSI layer 2 (L2)-originated indication that the handoff to a target OSI-based communications interface is imminent.

14. The MN of claim 8, wherein the processing unit is further adapted to receive, prior to handoff from an access network (AN) via the transceiver, additional data for use during handoff.

15. A method for link layer assisted handoff comprising:

sending, by an access network (AN) to a mobile node (MN), an OSI layer 2 (L2)-originated indication that a handoff to a target OSI-based communications interface is imminent;

sending, by the AN to the MN subsequent to the indication that the handoff is imminent, an OSI layer 2 (L2)-originated indication that a link to a serving OSI-based communications interface is down for the handoff to the target OSI-based communications interface.

16. The method of claim 15, further comprising

receiving, from the MN in response to the OSI layer 2 (L2)-originated indication that the handoff to a target OSI-based communications interface is imminent, a request that additional data for use during handoff be sent to the MN prior to handoff.

17. The method of claim 15, further comprising

sending, by the AN to the MN prior to handoff, additional data for use during handoff.

18. An access network (AN) comprising:

a transceiver;

a network interface;

a processing unit, communicatively coupled to the transceiver and the network interface,

adapted to provide an Open Systems Interconnection (OSI)-based communications interface for communication via the transceiver with a mobile node (MN);

adapted to send to the MN via the transceiver an OSI layer 2 (L2)-originated indication that a handoff to a target OSI-based communications interface is imminent;

adapted to send to the MN via the transceiver, subsequent to the indication that the handoff is imminent, an OSI layer 2 (L2)-originated indication that a link to a serving OSI-based communications interface is down for the handoff to the target OSI-based communications interface.

19. The AN of claim 18, wherein the processing unit is further adapted to receive, from the MN via the transceiver in response to the OSI layer 2 (L2)-originated indication that the handoff to a target OSI-based communications interface is imminent, a request that additional data for use during handoff be sent to the MN prior to handoff.

20. The MN of claim 18, wherein the processing unit is further adapted to send, to the MN via the transceiver prior to handoff, additional data for use during handoff.