Method of pre-authorizing handovers among access routers in communication networks

• US 20030092444A1
• Filed: 11/09/2001
• Published: 05/15/2003
• Est. Priority Date: 11/09/2001
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Nokia Corporation
• Inventors: Krishnamurthi, Govind, Sengodan, Senthil, Gopal, Ram
• Granted Patent: US 7,684,798 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 12/08 Access security
• CPC Class Codes: H04W 36/0016 Hand-off preparation specially adapted for end-to-end data sessions
• CPC Class Codes: H04W 88/005 Data network PoA devices

Abstract

An apparatus and method is provided for facilitating the handoff of a mobile terminal from a first access device in a first network to a second access device in a second network. Prior to performing a handoff operation, the first access device inquires as to whether the mobile terminal is authorized to be handed off to the second access device and, in response thereto, completes the handoff. If the mobile terminal is not authorized to be handed off to the second access device, the handoff operation is inhibited, preferably without using any radio frequency resources of the second access device.

Claims

1. A method of handing off a mobile terminal from a first network served by a first access device to a second network served by a second access device, comprising the steps of:

(1) sending an authorization inquiry from the first access device to the second access device including an identifier that identifies the mobile terminal;

(2) querying a database maintained by a home network associated with the mobile terminal to determine whether the mobile terminal is authorized to be handed off to the second access device;

(3) in response to determining that the mobile terminal is authorized to be handed off to the second access device, performing a handoff operation from the first access device to the second access device; and

(4) in response to determining that the mobile terminal is not authorized to be handed off to the second access device, inhibiting the handoff operation from the first access device to the second access device.

2. The method of claim 1, wherein step (3) comprises the step of transferring context information from the first access device to the second access device.

3. The method of claim 1, wherein steps (1) through (4) are performed without allocating any radio frequency resources of the second access device to communicate with the mobile terminal until after it is determined that the mobile terminal is authorized to be handed off to the second access device.

4. The method of claim 1, wherein step (2) comprises the step of querying the database on the basis of a list of access devices that are authorized to accept handoffs from the mobile terminal.

5. The method of claim 1, wherein step (2) comprises the step of querying the database to determine authorization based on a time of day.

6. The method of claim 1, wherein step (2) comprises the step of querying the database on the basis of a membership plan associated with a subscriber of the mobile terminal.

7. The method of claim 1, wherein step (2) comprises the step of querying the database on the basis of dynamic loading conditions.

8. The method of claim 1, further comprising the step of modifying the database on the basis of dynamic loading conditions, such that authorization is dependent upon dynamic loading conditions.

9. The method of claim 1, wherein steps (1) to (4) are conducted between access devices that use same access technology.

10. The method of claim 1, wherein steps (1) to (4) are conducted between access devices that use heterogeneous access technologies.

11. The method of claim 1, wherein step (2) comprises the steps of:

(a) sending the authorization inquiry to an administrative server associated with the second network; and

(b) sending the authorization inquiry from the administrative server to a home server that accesses the database.

12. The method of claim 11, wherein steps (a) and (b) are performed using the DIAMETER protocol.

13. The method of claim 11, wherein step (a) and (b) are performed using the Session Initiation Protocol (SIP) protocol.

14. An access router that serves mobile terminals within a service area, comprising a processor that performs the steps of:

(1) receiving from another access router that serves a different service area a request for authorization information concerning a mobile terminal that is a candidate for a handoff operation;

(2) causing a database to be queried to determine whether the access router is authorized to accept a handoff operation for the mobile terminal;

(3) in response to determining that the mobile terminal is authorized to be handed off to the access router, performing a handoff operation with the another access router; and

(4) in response to determining that the mobile terminal is not authorized to be handed off to the access router, inhibiting the handoff operation with the another access router.

15. The access router of claim 14, wherein step (3) comprises the step of transferring context information from the another access router to the access router.

16. The access router of claim 14, wherein steps (1) through (4) are performed without allocating any radio frequency resources of the access device to communicate with the mobile terminal until after it is determined that the mobile terminal is authorized to be handed off to the access device.

17. The access router of claim 14, wherein step (2) comprises the step of querying the database on the basis of a list of access devices that are authorized to accept handoffs from the mobile terminal.

18. The access router of claim 14, wherein step (2) comprises the step of querying the database to determine authorization that is dependent on a time of day.

19. The access router of claim 14, wherein step (2) comprises the step of querying the database on the basis of a membership plan associated with a subscriber of the mobile terminal.

20. The access router of claim 14, wherein step (2) comprises the step of querying the database on the basis of dynamic loading conditions.

21. The access router of claim 14, further comprising the step of providing information concerning current loading conditions to the database, such that authorization is dependent upon dynamic loading conditions.

22. The access router claim 14, wherein the access router serves mobile terminals using Internet Protocol.

23. The access router of claim 14, wherein the access router uses a different access technology than the another access router from which the candidate handoff is to be performed.

24. The access router of claim 23, wherein the access router uses wireless LAN technology, and wherein the another access router uses GPRS technology.

25. The access router of claim 14, wherein the access router uses the same access technology as the another access router from which the candidate handoff is to be performed.

26. The access router of claim 14, wherein step (2) comprises the step of sending an authorization inquiry to a home server associated with the mobile terminal.

27. The access router of claim 26, wherein step (2) is performed using the DIAMETER protocol.

28. The access router of claim 26, wherein step (2) is performed using the Session Initiation Protocol (SIP) protocol.

29. A method of handing off a mobile terminal from a first network served by a first access device to a second network served by a second access device, comprising the steps of:

(1) prior to initiating a handoff operation with the second access device, sending an authorization inquiry from the first access device to a home network associated with the mobile terminal, the authorization inquiry including an identifier that identifies the mobile terminal;

(2) receiving a result of a database query from the home network, wherein the result of the database query indicates whether the mobile terminal is authorized to be handed off to the second access device;

(3) in response to determining that the mobile terminal is authorized to be handed off to the second access device, performing a handoff operation from the first access device to the second access device; and

(4) in response to determining that the mobile terminal is not authorized to be handed off to the second access device, inhibiting the handoff operation from the first access device to the second access device.

30. The method of claim 29, wherein step (2) comprises the step of receiving a result that depends on dynamic loading conditions associated with the second access device.

31. The method of claim 29, wherein step (2) comprises the step of receiving a result corresponding to querying the database to determine authorization based on a time of day.

32. The method of claim 29, wherein step (2) comprises the step of receiving a result corresponding to querying the database on the basis of a membership plan associated with a subscriber of the mobile terminal.

33. The method of claim 29, wherein step (2) comprises the step of receiving a result corresponding to querying the database on the basis of dynamic loading conditions.

34. The method of claim 29, wherein steps (1) to (4) are performed without allocating any radio frequency resources for communicating between the second access device and the mobile terminal until after it has been determined that the mobile terminal is authorized to be handed off to the second access device.