Transferring context during hand-over of mobile node in a wireless network

• US 20060133320A1
• Filed: 11/25/2005
• Published: 06/22/2006
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Byoung-Chul, Kang, Byung-Chang
• Granted Patent: US 7,542,449 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 36/0055 Transmission or use of information for re-establishing the radio link
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

In transferring a service context during hand-over of a mobile node located in a wireless mesh network, transfer boundaries are set according to positions spaced from an initial Access Point (AP) to which the mobile node is initially connected to, AP types being determined based upon the set transfer boundaries. Prior to hand-over of the mobile node in response to its movement, a service context is transferred to APs arranged in a moving direction of the mobile node based upon context transfer policies according to the determined AP types.

Claims

1. A method of transferring a service context during a hand-over of a mobile node in a wireless mesh network, the method comprising:

setting transfer boundaries according to positions spaced from an initial Access Point (AP) initially connected to the mobile node and determining AP types based upon the set transfer boundaries; and

transferring a service context to APs arranged in a moving direction of the mobile node based upon context transfer policies according to the determined AP types prior to hand-over of the mobile node in response to its movement.

2. The method according to claim 1, wherein the APs are arranged in hops from the initial AP.

3. The method according to claim 1, wherein the transfer boundaries are at 1, 3 and 6 hops from the initial AP.

4. The method according to claim 1, wherein the AP types comprise Incremental Edge APs, including the initial AP and APs located at the transfer boundaries, and proactive transfer APs arranged at minus one (−

1) hop from the Incremental Edge APs.

5. The method according to claim 1, wherein each of the APs comprises a client list table to manage data regarding approaching mobile nodes.

6. The method according to claim 5, wherein the client list table includes at least one of a MAC address of the mobile node, a context transfer serial number, a connection between the mobile node and the AP, a hop count, a state of the AP and a pointer regarding validity context information.

7. The method according to claim 1, wherein the transfer boundaries are in three stages arranged at 1, 3 and 6 hops from the initial AP.

8. The method according to claim 1, wherein, in transferring a service context to APs arranged in a moving direction of the mobile node based upon context transfer policies according to the determined AP types, the initial AP initially connected to the mobile node is adapted to:

search a client list table for data of the mobile node; and

transfer a service context to APs spaced at one hop from the initial AP upon the client list table not containing data of the mobile node, and transfer a service context to at least one AP arranged in the moving direction of the mobile node according to the type of connected AP based upon the client list table containing data of the mobile node.

9. The method according to claim 8, wherein transferring a service context to APs spaced at one hop from the initial AP upon the client list table not containing data of the mobile node and transferring a service context to at least one AP arranged in the moving direction of the mobile node according to the type of connected AP based upon the client list table containing data of the mobile node comprises:

transferring a service context to surrounding APs arranged in the moving direction of the mobile node within a value corresponding to the square of the position of the proactive transfer AP upon the connected AP being a proactive transfer AP and receiving redundant probe request signals from the mobile node; and

confirming whether or not a proactive transfer AP has received a service context, and if not, transferring a service context to at least one AP at a one hop-added position with respect to the Incremental Edge AP in the moving direction of the mobile node upon the connected AP being an incremental transfer AP.

10. The method according to claim 8, wherein the service context transfer is performed in a second transfer boundary of three stage transfer boundaries.

11. The method according to claim 9, wherein the probe request signals from the mobile node are outputted at a scanning period for searching for a new AP.

12. A method of transferring a service context during a hand-over of a mobile node in a Wi-bro network, the method comprising:

setting transfer boundaries to increase in hop units according to positions from an initial Access Point (AP) initially connected to the mobile node and determining AP types based upon the set transfer boundaries; and

prior to hand-over of the node in response to its movement, transferring a service context to at least one AP subject to transfer selected based upon service context transfer policies according to the AP types.

13. An Access Point (AP) comprising:

a mobile node connected thereto during a hand-over in a wireless network; and

service context transfer policies defined according to AP types determined based upon transfer boundaries set to gradually increase according to positions from an initial AP initially connected to the mobile node;

wherein the AP is adapted to transfer a service context to surrounding APs according to the context transfer policies before hand-over of the mobile node in response to its movement; and

wherein the surrounding APs are arranged in a moving direction of the mobile node.

14. The AP according to claim 13, wherein the APs are arranged in hop units from the initial AP.

15. The AP according to claim 13, wherein the AP types comprise Incremental Edge APs, including the initial AP and APs located at the transfer boundaries, and proactive transfer APs located at minus one (−

1) hop from the Incremental Edge APs.

16. The AP according to claim 13, wherein the transfer boundaries are in three stages arranged at 1, 3 and 6 hops from the initial AP.

17. The AP according to claim 15, wherein the AP is adapted to:

transfer a service context to surrounding APs arranged in the moving direction of the mobile node within a value corresponding to the square of the position of the proactive transfer AP upon the connected AP being a proactive transfer AP and receive redundant probe request signals from the mobile node; and

confirm whether or not a proactive transfer AP has received a service context upon the connected AP being an incremental transfer AP, and transfer a service context to at least one AP at one hop-added position with respect to the Incremental Edge AP in the moving direction of the mobile node if not.

18. A system of transferring a service context during a hand-over of a mobile node arranged in a wireless mesh network, the system comprising:

a plurality of Access Points (APs) adapted to be connected to a mobile node during hand-over in the wireless mesh network, each of the APs having service context transfer policies defined according to AP types based upon transfer boundaries set to gradually increase according to positions from an initial AP initially connected to the mobile node, and adapted to transfer a service context to surrounding APs according to the context transfer policies before hand-over of the mobile node in response to its movement, wherein the surrounding APs are arranged in a moving direction of the mobile node; and

an access router adapted to interface the APs with the Internet;

wherein the mobile node is adapted to move in the wireless mesh network while changing its connection with the APs.