Handover resource optimization

• US 7,321,587 B2
• Filed: 11/15/2002
• Issued: 01/22/2008
• Est. Priority Date: 11/15/2002
• Status: Expired due to Fees

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Gao, Xia, Jeong, Moo R., Wu, Gang, Watanabe, Fujio
• Primary Examiner(s): Mehrpour; Naghmeh
• Application Number:
  US10/295,800
• Publication Number:
  US 20040095912A1
• Time in Patent Office: 1,894 Days
• Field of Search: 370/388, 370/401, 370/389, 370/468, 370/395.1, 370/332, 370/346, 370/395.2, 370/395.52, 455/388, 455/401, 455/389, 455/468, 455/395.1, 455/332, 455/346, 455/395.2, 455/395.52
• US Class Current: 370/388
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/0019 adapted for mobile IP [MIP]
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

A method for maintaining a quality of service in a wireless communication network is introduced. A reservation is created in a first data path between a home agent and a first foreign agent for data flow between the home agent and a wireless terminal. When the wireless terminal associates with a second foreign agent, a quality of service supportive second data path may be created between the first foreign agent and the second foreign agent. The data flow may be routed over the first and second data paths to maintain the quality of service for the data flow. A wireless communication network may include first downstream and reverse tunnels coupling a home agent and a first foreign agent, each tunnel having a reservation to maintain a quality of service. Second downstream and reverse tunnels may couple a home agent and a second foreign agent. All or part of the resources reserved by the first tunnels may be shared with the second tunnels when a wireless terminal hands over from the first foreign agent to the second foreign agent.

Claims

1. A method for maintaining a quality of service in a wireless communication network, comprising the steps of:

creating a first reservation in a first data path between a corresponding terminal and a wireless terminal, where the first data path includes a segment between a home agent and a first foreign agent;

creating a second reservation in a second data path between the corresponding terminal and the wireless terminal, where the second data path includes a segment between the home agent and a second foreign agent, and wherein the first and second data paths are distinct data paths; and

sharing a resource between the first and second reservations on a router common to the segments of the first and second data paths.

2. The method of claim 1, where the first data path includes a second segment between the corresponding terminal and the home agent and the second data path includes a second segment between the corresponding terminal and the home agent, further including the step of sharing a resource between the first and second reservations on a router common to the second segments of the first and second data paths.

3. The method of claim 1, where the step of sharing the resource further includes the steps of creating a tunnel between the home agent and the first foreign agent.

4. The method of claim 3, where the step of creating the tunnel further includes the step of creating an IP-IP tunnel.

5. The method of claim 3, where the step of creating a first reservation further includes the step transporting end-to-end reservation messages between the wireless terminal and the corresponding terminal through the tunnel.

6. The method of claim 1, where the step of creating a first reservation further includes the step transporting end-to-end reservation messages between the wireless terminal and the corresponding terminal.

7. The method of claim 2, where the step of transporting the end-to-end reservation messages further includes the step of transporting the end-to-end reservation messages transparently from the perspective of the wireless terminal and the corresponding terminal.

8. The method of claim 1, where the step of sharing a resource further includes the step of sending a shared explicit style reservation message including an address of the first foreign agent and a sender template.

9. The method of claim 8, where the step of sending a shared explicit style reservation message further includes the step of merging a second sender template from a second shared explicit style reservation message into the sender template.

10. The method of claim 9, where the shared explicit style reservation messages are of a common session.

11. The method of claim 1, where the step of sharing a resource further includes the step of sending, from the home agent to the first foreign agent, a reservation message including a first session object associated with a first destination port and a second session object associated with a second destination port.

12. The method of claim 1, where the destination ports are tunnel destination ports.

13. The method of claim 11, further including the step of substituting, in a memory of the router, the second session object for the first session object.

14. The method of claim 11, further including the step of selecting a unique destination port as the second destination port.

15. The method of claim 1, where the first data path consists essentially of a reverse tunnel for carrying data from the first foreign agent to the home agent, and second data path consists essentially of a reverse tunnel for carrying data from the second foreign agent to the home agent.

16. The method of claim 1, further including the steps transmitting data from a wireless terminal through the first foreign agent and the home agent to the corresponding terminal, and transmitting data from the wireless terminal through the second foreign agent and the home agent to the corresponding terminal.

17. The method of claim 16, where the step of transmitting data through the first foreign agent further includes the step of associating the wireless terminal with the first foreign agent.

18. The method of claim 16, where the step of transmitting data through the second foreign agent further includes the step of associating the wireless terminal with the second foreign agent, and disassociating the wireless terminal from the first foreign agent.

19. A method for maintaining a quality of service in a wireless communication network, comprising the steps of:

creating a first reservation in a first data path between a home agent and a router using a first session object;

creating the first reservation in a second data path between the router and a first foreign agent using the first session object;

creating a second reservation in a third data path between the router and a second foreign agent using the first session object and a second session object, wherein the second and third data paths are distinct data paths; and

creating the second reservation in the first data path using the first and the second session objects, where resources in the first data path are reserved by the first and the second reservation.

20. The method of claim 19, where the step of creating a second reservation in a third data path further includes the step of sending a reservation request message including the first and the second session objects from the second foreign agent, through the router to the home agent.

21. The method of claim 20, further including the steps of storing information from the second session object in a memory of the router, receiving a path tear-down message including the first session object at the router, and substituting the information from the second session object for the first session object in the memory.

22. The method of claim 19, where the first and second data paths form a forward tunnel for carrying data from the home agent to the first foreign agent.

23. The method of claim 19, where the first and third data paths form a forward tunnel for carrying data from the home agent to the second foreign agent.

24. The method of claim 19, further including the steps transmitting data from the home agent through the first foreign agent to a wireless terminal through, and transmitting data from the home agent through the second foreign agent to the wireless terminal.

25. A method for maintaining a quality of service in a wireless communication network, comprising the steps of:

creating a first reservation in a first data path between a first terminal and a second terminal;

creating a second reservation in a second data path between the first terminal and the second terminal, wherein the first and second data paths are distinct data paths; and

sharing a resource on a router common to the first and second reservations.

26. The method of claim 25, where the first terminal sends data to the second terminal.

27. The method of claim 25, further including the steps sending, from the first terminal, a shared explicit style reservation message that includes an address of the second terminal, a sender template, and a unique destination port number.

28. The method of claim 27, where the step of sending shared explicit style reservation message further includes the step of merging a second sender template from a second shared explicit style reservation message into the sender template.

29. The method of claim 27, where the address is a care-of address of the second terminal.

30. The method of claim 29, further including the steps of forming, with the second terminal, a new care-of-address, and sending a binding update message from the second terminal to the first terminal.

31. The method of claim 30, where sending the binding update message further includes the step of sending the binding update message from the second terminal to a home agent.

32. The method of claim 26, further including the steps of sending, from the second terminal to the first terminal a binding update message, reading an address of the second terminal from the binding update message, and sending a packet to the second terminal at the address.

33. The method of claim 25, further including the step of sending, from the second terminal through the router to the first terminal, a reservation request message including a first session object including a first address and a second session object including a second address.

34. The method of claim 25, where the addresses are care-of addresses.

35. A wireless communication network, comprising:

a home agent communicatively coupled to a corresponding terminal;

a first foreign agent communicatively coupled to a wireless terminal;

a first data flow originating at the corresponding terminal and terminating at the wireless terminal;

a second data flow originating at the wireless terminal and terminating at the corresponding terminal;

a first downstream tunnel coupled to the home agent and the first foreign agent, the first downstream tunnel reserving resources to carry the first data flow from the home agent to the first foreign agent at a first quality of service;

a first reverse tunnel coupled to the home agent and the first foreign agent, the first reverse tunnel reserving resources to carry the second data flow from the first foreign agent to the home agent at a second quality of service;

a second foreign agent communicatively coupled to the wireless terminal;

a second downstream tunnel coupled to the home agent and the second foreign agent, the second downstream tunnel sharing reserved resources of the first downstream tunnel to carry the first data flow from the home agent to the second foreign agent at the first quality of service;

a second reverse tunnel coupled to the home agent and the second foreign agen, the second reverse tunnel sharing reserved resources of the first reverse tunnel to carry the second data flow from the second foreign agent to the home agent at the second quality of service, wherein the reserved resources are shared between the first and second reverse tunnels and the first and second downstream tunnels during a handover of the wireless terminal from the first foreign agent to the second foreign agent.

36. The wireless communication network of claim 35, wherein the first and second downstream tunnels comprise a first common link, and the first and second reverse tunnels comprise a second common link, wherein the first common link comprises the shared reserved resources of the first and second downstream tunnels, and wherein the second common link comprises the shared resources of the first and second reverse tunnels.

37. The wireless communication network of claim 35, further comprising a quality of service path between the first foreign agent and the second foreign agent, wherein the quality of service path is configured to facilitate use of the first downstream tunnel and the first reverse tunnel for end-to-end communications between the wireless terminal and the corresponding terminal to achieve the first and second quality of services until the second downstream tunnel and the second reverse tunnel are operational.