Method and system for supporting mobility of mobile terminal

• US 7,573,846 B2
• Filed: 10/15/2004
• Issued: 08/11/2009
• Est. Priority Date: 10/27/2003
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Rue, Seon-Soo, Lee, Gui-Jung
• Primary Examiner(s): Milord; Marceau
• Application Number:
  US10/964,738
• Publication Number:
  US 20050089010A1
• Time in Patent Office: 1,761 Days
• Field of Search: 370/328, 370/338, 370/329, 370/331, 370/389, 370/255, 370/349, 370/312, 370/402, 370/401, 370/332, 370/352, 370/342, 455/433, 709/227, 709/229
• US Class Current: 370/329
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• CPC Class Codes: H04L 61/5084 Providing for device mobility network addressing or numbering for mobility support in wireless networks H04W8/26; mobile IP H04W80/04
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04W 8/082 for traffic bypassing of mobility servers, e.g. location registers, home PLMNs or home agents
• CPC Class Codes: H04W 8/12 between location registers or mobility servers
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 80/00 Wireless network protocols or protocol adaptations to wireless operation
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

A method and system for supporting mobility of a mobile node in which, when it is recognized that the mobile node has moved into a foreign sub-network, the mobile node is allocated, by its home sub-network, a new Internet protocol address suitable for a prefix of the foreign sub-network after movement when moving out of an area of the home sub-network into the foreign sub-network so that route optimization is implemented. Since direct communication is made between a mobile node and a correspondent node without passing a network where the mobile node existed before movement, it is possible to implement the route optimization. There is no generation of packet overhead since Internet protocol tunneling technology is not applied upon routing.

Claims

1. A method of supporting mobility of a mobile node using a mobile Internet protocol, the method comprising:

performing, by the mobile node, an active scan to thereby obtain an identifier of an access point that is determined to have high received electric field intensity;

comparing the obtained result with a previous identifier of an access point to thereby determine whether the mobile node has moved into another sub-network from a first sub-network;

when it is determined that the mobile node has moved into another sub-network, allocating by said first sub-network a new Internet protocol address to the mobile node, the Internet protocol address having a network prefix identical to that for the sub-network into which the mobile node has moved; and

directly routing, by said first sub-network, a data packet to the another sub-network after movement using the Internet protocol address allocated in the previous step.

2. The method of claims 1, wherein the step of comparing includes:

determining whether the identifier of the access point that is determined to have the high received electric field intensity is identical to that of a previous access point to determine whether the another subnet is identical to a previous sub-network;

when the identifiers of the access points are different from each other, determining that the another sub-net is a different sub-network; and

when the identifiers of the access points are identical to each other, determining that the another sub-net is the same sub-network.

3. The method of claim 2, wherein the mobile node manages registered access point identifiers of the access point identifiers obtained by the active scan.

4. The method of claim 2, wherein the mobile node is connected to an access point having the greatest received electric field intensity level value among access points having a registered identifier.

5. The method of claim 1, wherein the identifiers of the access points are extended service set identifications representing identifiers of the sub-networks.

6. The method of claim 5, wherein when the access points belong to the same sub-network, the extended service set identifications are the same.

7. The method of claim 1, wherein the active scan is performed when a level of received electric field intensity is lowered by a certain value upon movement of the mobile node.

8. The method of claim 1, wherein the active scan is periodically performed to confirm whether there are neighboring access points using any identifier.

9. The method of claim 1, wherein the mobile node is any one of a terminal with a wireless LAN (local area network) card mounted thereon and a terminal with bluetooth software mounted thereon.

10. The method of claim 1, wherein allocating the Internet protocol address to the mobile node, the Internet protocol address having the same network prefix as that after the movement, includes:

transmitting, by the mobile node, a dynamic host configuration protocol request frame to a dynamic host configuration protocol server upon connecting to an access point having an identifier different from an existing identifier; and

transmitting, by the dynamic host configuration protocol server, a response frame to the mobile node in response to the dynamic host configuration protocol request frame.

11. The method of claim 10, wherein upon transmitting the dynamic host configuration protocol request frame to the dynamic host configuration protocol server, the mobile node transmits the frame including a user identifier, password and authentication information in an option field of the frame.

12. The method of claim 10, wherein the access point performs a dynamic host configuration protocol relay function with a predefined dynamic host configuration protocol server, and transmits information obtained from the mobile node and access point media access control address information included in an option field to the dynamic host configuration protocol server.

13. The method of claim 12, wherein the access point performs the dynamic host configuration protocol relay function with the dynamic host configuration protocol server using one of a router, a hub, a bridge, and a switch.

14. The method of claim 10, the dynamic host configuration protocol server allocates an Internet protocol address of the mobile node using the received mobile node information and access point information, and transmits the newly allocated Internet protocol address to the access point.

15. The method of claim 10, wherein the dynamic host configuration protocol server transmits mobile node information to a home network managing an overall system.

16. The method of claim 1, comprising:

when there is a correspondent mobile node in communication with the mobile node that has moved into the another sub-network, directly routing a data packet to the sub-network into which the mobile node has moved by transmitting new Internet protocol address information of the moving mobile node to correspondent mobile node.

17. The method of claim 16, wherein a home network notifies the access point where the moving mobile node was previously positioned of an Internet protocol address change of the mobile node.

18. The method of claim 16, wherein the access point where the moving mobile node was previously positioned retransmits authentication information of the moving mobile node and data packets received during the movement to a new destination Internet protocol address.

19. A system for supporting mobility of mobile terminals in a system, comprising:

a home network agent allocating to a mobile node a new Internet protocol address having a network prefix identical to that for a sub-network into which said mobile node has moved, when an active scan is performed by the mobile node to thereby obtain an identifier of an access point that is determined to have high received electric field intensity, and a previous identifier is compared with the obtained result to thereby recognize that the mobile node has moved into another sub-network, the access points having identifiers identical to each other when the access points belong to the same sub-network; and

the home network agent directly routing a data packet to the another sub-network after movement by using the Internet protocol address allocated by the home network agent.

20. The system of claim 19, wherein the home network agent further comprises a dynamic host configuration protocol server, the server performing call management of an overall system, mobility sensing, initial registration of mobile nodes, statistics, database management, and allocation of the new Internet protocol address to the mobile node.

21. The system of claim 20, wherein upon moving into the another sub-network, the mobile node is allocated an Internet protocol address suitable for a network prefix after the movement from the dynamic host configuration protocol server.

22. The system of claim 20, the mobile node transmitting a dynamic host configuration protocol request frame to the dynamic host configuration protocol server, the request frame including a user identifier, password and authentication information in an option field of the frame.

23. The system of claim 20, wherein the access point performs a dynamic host configuration protocol relay function with a predefined dynamic host configuration protocol server, and transmits information obtained from the mobile node and access point media access control address information included in an option field to the dynamic host configuration protocol server of the home network agent.

24. The system of claim 23, wherein the access point performs the dynamic host configuration protocol relay function with the dynamic host configuration protocol server using one of a router, a hub, a bridge, and a switch.

25. The system of claim 20, the dynamic host configuration protocol server allocating the new Internet protocol address to the mobile node using received mobile node information and access point information, and transmitting the newly allocated Internet protocol address to the access point.

26. The system of claim 25, wherein the dynamic host configuration protocol server transmits the mobile node information to the home network managing the overall system.

27. The system of claim 19, wherein the identifiers of the access points are extended service set identifications representing identifiers of the sub-networks.

28. The system of claim 19, wherein the mobile node manages registered access point identifiers of access point identifiers obtained through an active scan.

29. The system claim 19, wherein the mobile node is connected to an access point having the greatest received electric field intensity level value among access points having a registered identifier.

30. The system of claim 19, wherein the home network notifies the access point where the moving mobile node was previously positioned of an Internet protocol address change of the mobile node.

31. The system of claim 19, wherein the access point where the moving mobile node was previously positioned retransmits authentication information of the moving mobile node and data packets received during the movement to a new destination Internet protocol address.

32. The system of claim 19, wherein the mobile node is any one of a terminal having a wireless LAN (local area network) card mounted thereon and a terminal having a bluetooth mounted thereon.