IDENTIFICATION OF TARGET NODE FOR WIRELESS HANDOFF

• US 20090097451A1
• Filed: 10/08/2008
• Published: 04/16/2009
• Est. Priority Date: 10/12/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gogic, Aleksandar M.
• Granted Patent: US 9,173,148 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 36/0058 Transmission of hand-off measurement information, e.g. measurement reports
• CPC Class Codes: H04W 36/12 Reselecting a serving backbone network switching or routing node
• CPC Class Codes: H04W 36/24 Reselection being triggered by specific parameters
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data

Abstract

Identification of an access point to which an access terminal is to be handed-off involves, in some aspects, identifying one access point of a set of access points that may have been detected by an access terminal. For example, an access terminal may receive a signal having an identified characteristic (e.g., a particular phase offset) from an access point. Each access point of a set of access points associated with the identified characteristic may be directed to attempt to decode a signal from the access terminal. The access point of the candidate set to use for the handoff operation may then be determined based on the signal received from the access terminal, if any, by each of the candidate access points.

Claims

1. A method of communication, comprising:

identifying a plurality of candidate target access points for a handoff operation for an access terminal;

sending a message to each of the candidate target access points to request each access point to attempt to process a signal from the access terminal;

receiving at least one response to at least one of the messages; and

identifying one of the access points for the handoff operation based on the at least one response.

2. The method of claim 1, wherein the identification of the candidate target access points comprises:

receiving an indication that an access terminal detected a signal having a defined characteristic; and

identifying access points in a defined geographic area that transmit signals with the defined characteristic.

3. The method of claim 2, wherein the identification of access points in the defined geographical area comprises identifying neighboring access points of a serving access point for the access terminal.

4. The method of claim 2, wherein the defined characteristic comprises a phase offset.

5. The method of claim 1, wherein the at least one response indicates a signal strength of a signal received at one of the access points from the access terminal.

6. The method of claim 1, wherein the identification of the one of the access points comprises:

determining, for each of the candidate target access points, a signal strength of a signal received from the access terminal;

determining which access point of the candidate target access points is associated with a highest one of the determined signal strengths.

7. The method of claim 1, wherein each message indicates at least one of the group consisting of:

an uplink spreading code used by the access terminal, a carrier frequency used by the access terminal, and how to respond to the message.

8. The method of claim 1, wherein the at least one response indicates whether at least one of the candidate target access points decoded a signal from the access terminal.

9. The method of claim 1, wherein each candidate target access point comprises a femto node or a pico node.

10. The method of claim 1, wherein the handoff comprises a hand-in from a macro access point to the identified one of the access points.

11. The method of claim 1, wherein:

each candidate target access point is restricted to not provide, for at least one other access terminal, at least one of the group consisting of;

signaling, data access, registration, and service; and

a decision to perform the handoff operation is based on whether the access terminal is authorized to access the identified one of the access points.

12. The method of claim 11, wherein the access terminal is handed-off to a femto channel used by the identified one of the access points if the access terminal is authorized to access the identified one of the access points.

13. An apparatus for communication, comprising:

means for identifying a plurality of candidate target access points for a handoff operation for an access terminal;

means for sending a message to each of the candidate target access points to request each access point to attempt to process a signal from the access terminal;

means for receiving at least one response to at least one of the messages; and

means for identifying one of the access points for the handoff operation based on the at least one response.

14. The apparatus of claim 13, wherein the identification of the candidate target access points comprises:

receiving an indication that an access terminal detected a signal having a defined characteristic; and

identifying access points in a defined geographic area that transmit signals with the defined characteristic.

15. The apparatus of claim 14, wherein the identification of access points in the defined geographical area comprises identifying neighboring access points of a serving access point for the access terminal.

16. The apparatus of claim 14, wherein the defined characteristic comprises a phase offset.

17. The apparatus of claim 13, wherein the at least one response indicates a signal strength of a signal received at one of the access points from the access terminal.

18. The apparatus of claim 13, wherein the identification of the one of the access points comprises:

determining, for each of the candidate target access points, a signal strength of a signal received from the access terminal;

determining which access point of the candidate target access points is associated with a highest one of the determined signal strengths.

19. The apparatus of claim 13, wherein each message indicates at least one of the group consisting of:

an uplink spreading code used by the access terminal, a carrier frequency used by the access terminal, and how to respond to the message.

20. The apparatus of claim 13, wherein the at least one response indicates whether at least one of the candidate target access points decoded a signal from the access terminal.

21. The apparatus of claim 13, wherein each candidate target access point comprises a femto node or a pico node.

22. The apparatus of claim 13, wherein the handoff comprises a hand-in from a macro access point to the identified one of the access points.

23. The apparatus of claim 13, wherein:

each candidate target access point is restricted to not provide, for at least one other access terminal, at least one of the group consisting of;

signaling, data access, registration, and service; and

a decision to perform the handoff operation is based on whether the access terminal is authorized to access the identified one of the access points.

24. The apparatus of claim 23, wherein the access terminal is handed-off to a femto channel used by the identified one of the access points if the access terminal is authorized to access the identified one of the access points.

25. An apparatus for communication, comprising:

a candidate identifier configured to identify a plurality of candidate target access points for a handoff operation for an access terminal and send a message to each of the candidate target access points to request each access point to attempt to process a signal from the access terminal; and

a target identifier configured to receive at least one response to at least one of the messages to identify one of the access points for the handoff operation based on the at least one response.

26. The apparatus of claim 25, wherein the identification of the candidate target access points comprises:

receiving an indication that an access terminal detected a signal having a defined characteristic; and

identifying access points in a defined geographic area that transmit signals with the defined characteristic.

27. The apparatus of claim 26, wherein the identification of access points in the defined geographical area comprises identifying neighboring access points of a serving access point for the access terminal.

28. The apparatus of claim 26, wherein the defined characteristic comprises a phase offset.

29. The apparatus of claim 25, wherein the identification of the one of the access points comprises:

determining, for each of the candidate target access points, a signal strength of a signal received from the access terminal;

determining which access point of the candidate target access points is associated with a highest one of the determined signal strengths.

30. A computer-program product, comprising:

computer-readable medium comprising codes for causing a computer to;

identify a plurality of candidate target access points for a handoff operation for an access terminal;

send a message to each of the candidate target access points to request each access point to attempt to process a signal from the access terminal;

receive at least one response to at least one of the messages; and

identify one of the access points for the handoff operation based on the at least one response.

31. The computer-program product of claim 30, wherein the identification of the candidate target access points comprises:

receiving an indication that an access terminal detected a signal having a defined characteristic; and

identifying access points in a defined geographic area that transmit signals with the defined characteristic.

32. The computer-program product of claim 31, wherein the identification of access points in the defined geographical area comprises identifying neighboring access points of a serving access point for the access terminal.

33. The computer-program product of claim 31, wherein the defined characteristic comprises a phase offset.

34. The computer-program product of claim 30, wherein the identification of the one of the access points comprises:

determining, for each of the candidate target access points, a signal strength of a signal received from the access terminal;

determining which access point of the candidate target access points is associated with a highest one of the determined signal strengths.

35. A method of communication, comprising:

receiving, at an access point, a request to the access point to attempt to process a signal transmitted by an access terminal;

processing a signal received from the access terminal; and

transmitting a response to the request, wherein the response indicates a signal strength of the received signal.

36. The method of claim 35, wherein:

the processing comprises decoding; and

the response further indicates that the access point decoded the received signal.

37. The method of claim 35, wherein the request indicates a carrier frequency used by the access terminal.

38. The method of claim 35, wherein the request indicates how to respond to the request.

39. The method of claim 35, wherein the request indicates an uplink spreading code used by the access terminal.

40. The method of claim 35, further comprising receiving a handoff request in response to the response.

41. The method of claim 35, wherein the access point comprises a femto node or a pico node.

42. The method of claim 35, wherein the handoff comprises a hand-in from a macro access point to the access point.

43. The method of claim 35, wherein the access point is restricted to not provide, for at least one other access terminal, at least one of the group consisting of:

signaling, data access, registration, and service.

44. An apparatus for communication, comprising:

means for receiving, at an access point, a request to the access point to attempt to process a signal transmitted by an access terminal;

means for processing a signal received from the access terminal; and

means for transmitting a response to the request, wherein the response indicates a signal strength of the received signal.

45. The apparatus of claim 44, wherein:

the processing comprises decoding; and

the response further indicates that the access point decoded the received signal.

46. The apparatus of claim 44, wherein the request indicates a carrier frequency used by the access terminal.

47. The apparatus of claim 44, wherein the request indicates how to respond to the request.

48. The apparatus of claim 44, wherein the request indicates an uplink spreading code used by the access terminal.

49. The apparatus of claim 44, wherein the means for receiving is configured to receive a handoff request in response to the response.

50. The apparatus of claim 44, wherein the access point comprises a femto node or a pico node.

51. The apparatus of claim 44, wherein the handoff comprises a hand-in from a macro access point to the access point.

52. The apparatus of claim 44, wherein the access point is restricted to not provide, for at least one other access terminal, at least one of the group consisting of:

signaling, data access, registration, and service.

53. An apparatus for communication, comprising:

an acquisition request processor configured to receive, at an access point, a request to the access point to attempt to acquire a signal transmitted by an access terminal;

a signal processor configured to process a signal received from the access terminal; and

a response generator configured to transmit a response to the request, wherein the response indicates a signal strength of the received signal.

54. The apparatus of claim 53, wherein:

the processing comprises decoding; and

the response further indicates that the access point decoded the received signal.

55. The apparatus of claim 53, wherein the request indicates at least one of the group consisting of:

an uplink spreading code used by the access terminal, a carrier frequency used by the access terminal, and how to respond to the request.

56. The apparatus of claim 53, further comprising a handoff controller configured to receive a handoff request in response to the response.

57. A computer-program product, comprising:

computer-readable medium comprising codes for causing a computer to;

receive, at an access point, a request to the access point to attempt to process a signal transmitted by an access terminal;

process a signal received from the access terminal; and

transmit a response to the request, wherein the response indicates a signal strength of the received signal.

58. The computer-program product of claim 57, wherein:

the processing comprises decoding; and

the response further indicates that the access point decoded the received signal.

59. The computer-program product of claim 57, wherein the request indicates at least one of the group consisting of:

an uplink spreading code used by the access terminal, a carrier frequency used by the access terminal, and how to respond to the request.