METHOD AND APPARATUS FOR MEDIA INDEPENDENT HANDOVER

• US 20080175253A1
• Filed: 01/17/2008
• Published: 07/24/2008
• Est. Priority Date: 01/18/2007
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Rahman, Shamim Akbar, Olvera-Hernandez, Ulises, Watfa, Mahmoud
• Granted Patent: US 8,134,955 B2
• Time in Patent Office: Days
• US Class Current: 370/395.52
• CPC Class Codes: H04L 65/1016 IP multimedia subsystem [IMS]
• CPC Class Codes: H04L 65/1083 In-session procedures
• CPC Class Codes: H04L 65/1095 Inter-network session transfer or sharing
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/005 involving radio access media independent information, e.g. MIH [Media independent Hand-off]
• CPC Class Codes: H04W 36/144 over a different radio air interface technology
• CPC Class Codes: H04W 80/10 adapted for application session management, e.g. SIP [Session Initiation Protocol] connection management H04W76/00; arrangements for session management H04L67/14

Abstract

A method and apparatus for performing a handover are disclosed. An Internet protocol (IP) multimedia subsystem (IMS) client registers with an IMS network and establishes a media independent handover (MIH) session with an MIH application server using a session initiation protocol (SIP). The IMS client establishes a session for IP-based service, (e.g., voice over IP (VoIP)), with a communication peer using an SIP. MIH messages are exchanged for handover with the MIH application server over IP. After handover, the session is resumed. A serving call session control function (S-CSCF) triggers the MIH application server based on a string “MIH services” and a unique identifier included in an INVITE request. The IMS client may send a REFER request to the MIH application server after the handover to resume the session. Alternatively, the IMS client may send a RE-INVITE request to the MIH application server and the communication peer.

Claims

1. A method of performing a handover, the method comprising:

registering with an Internet protocol (IP) multimedia subsystem (IMS) network;

establishing a media independent handover (MIH) session with an MIH application server using a session initiation protocol (SIP);

establishing a session for IP-based service with a communication peer using an SIP;

detecting a need for a handover;

exchanging an MIH message for a handover with the MIH application server over an IP; and

performing a handover and resuming the session for IP-based service.

2. The method of claim 1 wherein the MIH session is established by sending an INVITE request to a serving call session control function (S-CSCF), which triggers the MIH application server.

3. The method of claim 2 wherein the INVITE request includes a string “

MIH services” and

a unique identifier of an IMS client.

4. The method of claim 3 wherein the unique identifier is an MIH function (MIHF) identifier.

5. The method of claim 1 further comprising:

performing a capability discovery procedure with the MIH application server over an IP.

6. The method of claim 1 further comprising:

performing an MIH registration procedure with the MIH application server over an IP.

7. The method of claim 1 further comprising:

performing an event subscription procedure with the MIH application server over an IP.

8. The method of claim 1 further comprising:

sending a signal strength report to the MIH application server over an IP;

receiving neighbor list information from the MIH application server over an IP;

sending a neighbor cell signal strength report to the MIH application server over an IP;

receiving a handover command from the MIH application server over an IP; and

sending a result of handover to the MIH application server over an IP.

9. The method of claim 1 wherein a REFER request is sent to the MIH application server after the handover using an SIP and the MIH application server sends an INVITE request to the communication peer to resume the session for IP-based service.

10. The method of claim 9 wherein the REFER request includes a string “

MIH services” and

a unique identifier of an IMS client.

11. The method of claim 10 wherein the unique identifier is an MIH function (MIHF) identifier.

12. The method of claim 1 wherein a RE-INVITE request is sent to the MIH application server and the communication peer after the handover to resume the session for IP-based service.

13. The method of claim 12 wherein the RE-INVITE request includes a string “

MIH services” and

a unique identifier of an IMS client.

14. The method of claim 13 wherein the unique identifier is an MIH function (MIHF) identifier.

15. The method of claim 1 further comprising:

sending a deregistration request to the MIH application server over an IP; and

sending a BYE request to the MIH application server to terminate the MIH session.

16. A method of performing a handover, the method comprising:

receiving an INVITE request from an Internet protocol (IP) multimedia subsystem (IMS) client via a serving call session control function (S-CSCF);

creating a binding for the IMS client;

establishing a media independent handover (MIH) session with the IMS client using a session initiation protocol (SIP); and

exchanging an MIH message for a handover with the IMS client over an IP.

17. The method of claim 16 further comprising:

sending a handover command to the IMS client; and

receiving a handover result from the IMS client.

18. The method of claim 17 further comprising:

receiving a REFER request from the IMS client;

updating the binding; and

sending an INVITE request to a communication peer as requested in the REFER request.

19. The method of claim 18 wherein the REFER request includes a string “

MIH services” and

a unique identifier of an IMS client.

20. The method of claim 19 wherein the unique identifier is an MIH function (MIHF) identifier.

21. The method of claim 17 further comprising:

receiving a RE-INVITE request from the IMS client; and

updating the binding.

22. The method of claim 21 wherein the RE-INVITE request includes a string “

MIH services” and

a unique identifier of an IMS client.

23. The method of claim 22 wherein the unique identifier is an MIH function (MIHF) identifier.

24. The method of claim 16 wherein the INVITE request includes a string “

MIH services” and

a unique identifier of an IMS client.

25. The method of claim 24 wherein the unique identifier is an MIH function (MIHF) identifier.

26. The method of claim 16 wherein a registration state and registration timer is maintained in the binding for the IMS client.

27. The method of claim 26 wherein the registration state is one of an unregistered state, a pending registration state, a registered and active state, a registered and inactive state, and a pending deregistration state.

28. A wireless transmit/receive unit (WTRU) for performing a handover, the WTRU comprising:

an Internet protocol (IP) multimedia subsystem (IMS) application layer configured to establish a session for IP-based service with a communication peer using a session initiation protocol (SIP);

a service policy entity configured to establish a media independent handover (MIH) session with an MIH application server using an SIP and perform a handover so that the session for IP-based service is resumed after the handover; and

an MIH function entity configured to exchange an MIH message with the MIH application server over an IP.

29. The WTRU of claim 28 wherein the MIH session is established by sending an INVITE request to a serving call session control function (S-CSCF), which triggers the MIH application server.

30. The WTRU of claim 29 wherein the INVITE request includes a string “

MIH services” and

a unique identifier of an IMS client.

31. The WTRU of claim 30 wherein the unique identifier is an MIH function (MIHF) identifier.

32. The WTRU of claim 28 wherein the MIH function entity is configured to perform a capability discovery procedure with the MIH application server over an IP.

33. The WTRU of claim 28 wherein the MIH function entity is configured to perform an MIH registration procedure with the MIH application server over an IP.

34. The WTRU of claim 28 wherein the MIH function entity is configured to perform an event subscription procedure with the MIH application server over an IP.

35. The WTRU of claim 28 wherein the MIH function entity is configured to send a signal strength report to the MIH application server over an IP, receive neighbor list information from the MIH application server over an IP, send a neighbor cell signal strength report to the MIH application server over an IP, receive a handover command from the MIH application server over an IP, and send a result of handover to the MIH application server over an IP.

36. The WTRU of claim 28 wherein a REFER request is sent to the MIH application server after the handover using an SIP requesting the MIH application server to send an INVITE request to the communication peer to resume the session for IP-based service.

37. The WTRU of claim 36 wherein the REFER request includes a string “

MIH services” and

a unique identifier of an IMS client.

38. The WTRU of claim 37 wherein the unique identifier is an MIH function (MIHF) identifier.

39. The WTRU of claim 28 wherein a RE-INVITE request is sent to the MIH application server and the communication peer after the handover to resume the session for IP-based service.

40. The WTRU of claim 39 wherein the RE-INVITE request includes a string “

MIH services” and

a unique identifier of an IMS client.

41. The WTRU of claim 40 wherein the unique identifier is an MIH function (MIHF) identifier.

42. A media independent handover (MIH) application server for supporting a handover, the MIH application server comprising:

a session initiation protocol (SIP) interface for receiving an INVITE request from an Internet protocol (IP) multimedia subsystem (IMS) client via a serving call session control function (S-CSCF);

a mobility and handover policy function (MHPF) entity for creating a binding for the IMS client and establishing an MIH session with the IMS client; and

an MIH function entity for exchanging an MIH message for a handover with the IMS client over an IP.

43. The MIH application server of claim 42 wherein the MIH function entity is configured to send a handover command to the IMS client and receive a handover result from the IMS client.

44. The MIH application server of claim 43 wherein the MHPF entity is configured to update the binding based on a REFER request from the IMS client.

45. The MIH application server of claim 44 wherein the REFER request includes a string “

MIH services” and

a unique identifier of an IMS client.

46. The MIH application server of claim 45 wherein the unique identifier is an MIH function (MIHF) identifier.

47. The MIH application server of claim 43 wherein the MHPF entity is configured to update the binding based on a RE-INVITE request from the IMS client.

48. The MIH application server of claim 47 wherein the RE-INVITE request includes a string “

MIH services” and

a unique identifier of an IMS client.

49. The MIH application server of claim 48 wherein the unique identifier is an MIH function (MIHF) identifier.

50. The MIH application server of claim 42 wherein the INVITE request includes a string “

MIH services” and

a unique identifier of an IMS client.

51. The MIH application server of claim 50 wherein the unique identifier is an MIH function (MIHF) identifier.

52. The MIH application server of claim 42 wherein a registration state and registration timer is maintained in the binding for the IMS client.

53. The MIH application server of claim 52 wherein the registration state is one of an unregistered state, a pending registration state, a registered and active state, a registered and inactive state, and a pending deregistration state.