Adaptive IP handoff triggering and iterative tuning of IP handoff trigger timing

• US 20030119508A1
• Filed: 06/27/2002
• Published: 06/26/2003
• Est. Priority Date: 12/21/2001
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Takeshita, Atsushi, Funato, Daichi, Fu, Guangrui, Gwon, Youngjune
• Granted Patent: US 7,206,579 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data

Abstract

A method and system for providing an adaptive IP handoff triggering system for a wireless communication system that consists of either the same or heterogeneous wireless access technologies. A mobile node is notified of at least one pre-trigger timing parameter by a current access network. At least one variable handoff threshold is constructed with the mobile node based on the at least one pre-trigger timing parameter. An IP handoff is then initiated to a candidate access network when pilot beacon signal strength of the mobile node reaches the variable handoff threshold.

Claims

1. A method for providing an adaptive handoff triggering system for a wireless communication system that consists of either the same or heterogeneous wireless access technologies, comprising the steps of:

notifying a mobile node of at least one pre-trigger timing parameter with a current access network;

constructing at least one variable handoff threshold with said mobile node based on said at least one pre-trigger timing parameter; and

initiating a handoff to a candidate access network when a pilot beacon signal strength on said mobile node reaches said variable handoff threshold.

2. The method of claim 1, further comprising the step of reporting a blackout duration to said current access network with said mobile node.

3. The method of claim 2, further comprising the step of retuning said pre-trigger timing parameter based on said blackout period with said current access network.

4. The method of claim 3, wherein an adaptive tuner is used to retune said pre-trigger timing parameter.

5. The method of claim 4, wherein said adaptive tuner uses an adaptive algorithm to retune said pre-trigger timing parameter.

6. The method of claim 5, wherein said adaptive algorithm comprises a least mean square algorithm.

7. The method of claim 1, wherein said variable handoff threshold is above a signal link down threshold.

8. The method of claim 1, wherein said variable handoff threshold is calculated based on a mathematical mapping equation.

9. The method of claim 8, wherein said mathematical mapping equation is defined as

10. An adaptive handoff triggering system for a wireless access network that consists of either the same or heterogeneous wireless access technologies, comprising:

an active access network connected to a mobile node, wherein said mobile node is provided with at least one pre-trigger timing parameter by said current access network, wherein said mobile node constructs at least one variable handoff threshold based on said at least one pre-trigger timing parameter; and

at least one candidate access network within radio range of said mobile node, wherein a handoff is initiated to said candidate access network when a beacon pilot signal strength on said mobile node reaches said variable handoff threshold.

11. The adaptive handoff triggering system of claim 10, wherein an IP blackout duration is reported to said current access network by said mobile node.

12. The adaptive handoff triggering system of claim 11, wherein said pre-trigger timing parameter is retuned based on said blackout duration by said current access network.

13. The adaptive handoff triggering system of claim 12, wherein an adaptive tuner is used to retune said pre-trigger timing parameter.

14. The adaptive handoff triggering system of claim 13, wherein said adaptive tuner uses an adaptive algorithm to retune said pre-trigger timing parameter.

15. The adaptive handoff triggering system of claim 14, wherein said adaptive algorithm comprises a least mean square algorithm.

16. The adaptive handoff triggering system of claim 10, wherein said variable handoff threshold is above a signal link down threshold.

17. The adaptive handoff triggering system of claim 10, wherein said variable handoff threshold is calculated based on a mathematical mapping equation.

18. The adaptive handoff triggering system of claim 17, wherein said mathematical mapping equation is defined as

19. A method for providing an adaptive handoff triggering system for a wireless communication system that consists of either the same or heterogeneous wireless access technologies, comprising the steps of:

transmitting a pre-trigger timing parameter to a mobile node;

measuring a beacon pilot signal strength between said mobile node and a current access network; and

triggering a handoff to a candidate access network when said beacon pilot signal strength reaches a variable handoff threshold.

20. A method for providing an adaptive handoff triggering system for a wireless communication system, comprising the steps of:

notifying a mobile node of at least one pre-trigger timing parameter with a current access network;

constructing at least one variable handoff threshold with said mobile node based on said at least one pre-trigger timing parameter;

initiating a handoff to a candidate access network when a pilot beacon signal strength on said mobile node reaches said variable handoff threshold;

reporting an IP blackout duration to said current access network with said mobile node; and

retuning said pre-trigger timing parameter based on said blackout duration with said current access network.