MULTI-FREQUENCY PILOT SIGNALS

• US 20100315967A1
• Filed: 06/08/2010
• Published: 12/16/2010
• Est. Priority Date: 06/11/2009
• Status: Abandoned Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Yavuz, Mehmet, Patel, Chirag Sureshbhai
• Application Number:
  US12/796,521
• Publication Number:
  US 20100315967A1
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7083 Cell search, e.g. using a three-step approach
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 48/20 Selecting an access point

Abstract

An access point is identified based on pilot signal information that appears on different frequencies. Here, a combination of one or more pilot PN spreading codes or one or more PN offsets on different frequencies are used to uniquely identify an access point. For example, upon receipt of a pilot measurement report, a network entity may uniquely identify an access point that transmitted the pilot signals based on at least one pilot PN spreading code or at least one PN offset and a plurality of frequencies identified by the report. Also, to facilitate acquiring this information, a network entity may request an access terminal to conduct an inter-frequency search for pilot signals. Also, an access terminal may maintain pilot information corresponding to access points in a network and use this information to autonomously conduct inter-frequency searches for pilot signals.

Claims

1. A method of communication, comprising:

receiving pilot measurement information that identifies pilot PN spreading code information corresponding to pilot signals transmitted on a plurality of frequencies and received by an access terminal; and

identifying an access point that transmitted the pilot signals based on the identified pilot PN spreading code information and plurality of frequencies.

2. The method of claim 1, wherein the pilot PN spreading code information comprises at least one pilot PN spreading code or at least one PN offset.

3. The method of claim 1, wherein the pilot PN spreading code information indicates that the pilot signals were transmitted on the plurality of frequencies using a single pilot PN spreading code and/or a single PN offset.

4. The method of claim 1, wherein the pilot PN spreading code information indicates that the pilot signals were transmitted on the plurality of frequencies using a plurality of pilot PN spreading codes and/or a plurality of PN offsets.

5. The method of claim 1, wherein the pilot PN spreading code information indicates that a portion of the pilot signals were transmitted on one of the plurality of frequencies using a plurality of pilot PN spreading codes and/or a plurality of PN offsets.

6. The method of claim 1, further comprising maintaining information that associates the access point with the pilot PN spreading code information and the plurality of frequencies, wherein the identification of the access point is based on the maintained information.

7. The method of claim 1, wherein the plurality of frequencies comprise a service frequency used by the access point and at least one beacon frequency used by the access point.

8. The method of claim 1, wherein the identification of the access point is further based on pilot strength information associated with the pilot signals.

9. The method of claim 1, further comprising initiating handover of the access terminal to the access point as a result of the identification of the access point.

10. The method of claim 1, wherein the identification of the access point comprises:

identifying the access point as a candidate that potentially sent the pilot signals based on the identified pilot PN spreading code information and plurality of frequencies;

identifying at least one other access point as at least one other candidate that potentially sent the pilot signals based on the identified pilot PN spreading code information and plurality of frequencies;

sending messages to the access point and the at least one other access point as a result of the identifications of the access points as candidates, wherein the messages request the access points to monitor for signals from the access terminal;

receiving at least one response to the messages, wherein the at least one response indicates whether at least one of the access points received signals from the access terminal; and

identifying the access point as a handover target based on the at least one response.

11. The method of claim 1, wherein the identification of the access point is performed by another access point that receives the pilot measurement information from the access terminal via a pilot measurement report.

12. The method of claim 1, wherein the identification of the access point is performed at a network entity that receives the pilot measurement information from another access point that receives the pilot measurement information from the access terminal.

13. The method of claim 1, wherein the access point comprises a femto access point.

14. An apparatus for communication, comprising:

a receiver configured to receive pilot measurement information that identifies pilot PN spreading code information corresponding to pilot signals transmitted on a plurality of frequencies and received by an access terminal; and

a pilot processor configured to identify an access point that transmitted the pilot signals based on the identified pilot PN spreading code information and plurality of frequencies.

15. The apparatus of claim 14, wherein the pilot PN spreading code information comprises at least one pilot PN spreading code or at least one PN offset.

16. The apparatus of claim 14, further comprising a storage component configured to maintain information that associates the access point with the pilot PN spreading code information and the plurality of frequencies, wherein the identification of the access point is based on the maintained information.

17. The apparatus of claim 14, wherein the plurality of frequencies comprise a service frequency used by the access point and at least one beacon frequency used by the access point.

18. The apparatus of claim 14, wherein the identification of the access point is further based on pilot strength information associated with the pilot signals.

19. An apparatus for communication, comprising:

means for receiving pilot measurement information that identifies pilot PN spreading code information corresponding to pilot signals transmitted on a plurality of frequencies and received by an access terminal; and

means for identifying an access point that transmitted the pilot signals based on the identified pilot PN spreading code information and plurality of frequencies.

20. The apparatus of claim 19, wherein the pilot PN spreading code information comprises at least one pilot PN spreading code or at least one PN offset.

21. The apparatus of claim 19, further comprising means for maintaining information that associates the access point with the pilot PN spreading code information and the plurality of frequencies, wherein the identification of the access point is based on the maintained information.

22. The apparatus of claim 19, wherein the plurality of frequencies comprise a service frequency used by the access point and at least one beacon frequency used by the access point.

23. The apparatus of claim 19, wherein the identification of the access point is further based on pilot strength information associated with the pilot signals.

24. A computer-program product, comprising:

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

receive pilot measurement information that identifies pilot PN spreading code information corresponding to pilot signals transmitted on a plurality of frequencies and received by an access terminal; and

identify an access point that transmitted the pilot signals based on the identified pilot PN spreading code information and plurality of frequencies.

25. The computer-program product of claim 24, wherein the pilot PN spreading code information comprises at least one pilot PN spreading code or at least one PN offset.

26. The computer-program product of claim 24, wherein:

the computer-readable medium further comprises code for causing the computer to maintain information that associates the access point with the pilot PN spreading code information and the plurality of frequencies; and

the identification of the access point is based on the maintained information.

27. The computer-program product of claim 24, wherein the plurality of frequencies comprise a service frequency used by the access point and at least one beacon frequency used by the access point.

28. The computer-program product of claim 24, wherein the identification of the access point is further based on pilot strength information associated with the pilot signals.

29. A method of communication, comprising:

receiving pilot measurement information that indicates that an access terminal received a pilot signal on a first frequency; and

sending a message as a result of the receipt of the pilot measurement information, wherein the message requests the access terminal to conduct a pilot signal search on at least one other frequency.

30. The method of claim 29, wherein the message specifies the at least one other frequency on which the access terminal is to conduct the pilot signal search.

31. The method of claim 30, wherein:

the pilot measurement information identifies a pilot PN spreading code and/or a PN offset used to transmit the pilot signal on the first frequency; and

the method further comprises selecting the at least one other frequency that is specified by the message based on the identified pilot PN spreading code and/or PN offset.

32. The method of claim 29, wherein the message comprises an indication of at least one pilot PN spreading code and/or at least one PN offset used on the at least one other frequency.

33. The method of claim 32, wherein:

the pilot measurement information identifies a pilot PN spreading code and/or a PN offset used to transmit the pilot signal on the first frequency; and

the method further comprises determining the at least one pilot PN spreading code and/or at least one PN offset used on the at least one other frequency based on the identified pilot PN spreading code and/or PN offset.

34. The method of claim 29, further comprising:

receiving additional pilot measurement information as a result of sending the message, wherein the additional pilot information identifies at least one pilot PN spreading code and/or at least one PN offset associated with at least one other pilot signal received by the access terminal on the at least one other frequency; and

identifying an access point that transmitted the pilot signal and the at least one other pilot signal based on the additional pilot measurement information.

35. The method of claim 34, wherein the access point comprises a femto access point.

36. The method of claim 34, further comprising initiating handover of the access terminal to the access point as a result of the identification of the access point.

37. The method of claim 29, wherein the message is sent by an access point that receives the pilot measurement information from the access terminal via a pilot measurement report.

38. The method of claim 29, wherein:

the pilot measurement information is received by a network entity from an access point that received the pilot measurement information from the access terminal;

the message is sent by the network entity to the access point; and

the access point sends a request to the access terminal to conduct the pilot search as a result of receiving the message from the network entity.

39. An apparatus for communication, comprising:

a receiver configured to receive pilot measurement information that indicates that an access terminal received a pilot signal on a first frequency; and

a pilot processor configured to send a message as a result of the receipt of the pilot measurement information, wherein the message requests the access terminal to conduct a pilot signal search on at least one other frequency.

40. The apparatus of claim 39, wherein the message specifies the at least one other frequency on which the access terminal is to conduct the pilot signal search.

41. The apparatus of claim 40, wherein:

the pilot measurement information identifies a pilot PN spreading code and/or a PN offset used to transmit the pilot signal on the first frequency; and

the pilot processor is further configured to select the at least one other frequency that is specified by the message based on the identified pilot PN spreading code and/or PN offset.

42. The apparatus of claim 39, wherein the message comprises an indication of at least one pilot PN spreading code and/or at least one PN offset used on the at least one other frequency.

43. The apparatus of claim 42, wherein:

the pilot measurement information identifies a pilot PN spreading code and/or a PN offset used to transmit the pilot signal on the first frequency; and

the pilot processor is further configured to determine the at least one pilot PN spreading code and/or at least one PN offset used on the at least one other frequency based on the identified pilot PN spreading code and/or PN offset.

44. An apparatus for communication, comprising:

means for receiving pilot measurement information that indicates that an access terminal received a pilot signal on a first frequency; and

means for sending a message as a result of the receipt of the pilot measurement information, wherein the message requests the access terminal to conduct a pilot signal search on at least one other frequency.

45. The apparatus of claim 44, wherein the message specifies the at least one other frequency on which the access terminal is to conduct the pilot signal search.

46. The apparatus of claim 45, wherein:

the pilot measurement information identifies a pilot PN spreading code and/or a PN offset used to transmit the pilot signal on the first frequency; and

the apparatus further comprises means for selecting the at least one other frequency that is specified by the message based on the identified pilot PN spreading code and/or PN offset.

47. The apparatus of claim 44, wherein the message comprises an indication of at least one pilot PN spreading code and/or at least one PN offset used on the at least one other frequency.

48. The apparatus of claim 47, wherein:

the pilot measurement information identifies a pilot PN spreading code and/or a PN offset used to transmit the pilot signal on the first frequency; and

the apparatus further comprises means for determining the at least one pilot PN spreading code and/or at least one PN offset used on the at least one other frequency based on the identified pilot PN spreading code and/or PN offset.

49. A computer-program product, comprising:

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

receive pilot measurement information that indicates that an access terminal received a pilot signal on a first frequency; and

send a message as a result of the receipt of the pilot measurement information, wherein the message requests the access terminal to conduct a pilot signal search on at least one other frequency.

50. The computer-program product of claim 49, wherein the message specifies the at least one other frequency on which the access terminal is to conduct the pilot signal search.

51. The computer-program product of claim 50, wherein:

the pilot measurement information identifies a pilot PN spreading code and/or a PN offset used to transmit the pilot signal on the first frequency; and

the computer-readable medium further comprises code for causing the computer to select the at least one other frequency that is specified by the message based on the identified pilot PN spreading code and/or PN offset.

52. The computer-program product of claim 49, wherein the message comprises an indication of at least one pilot PN spreading code and/or at least one PN offset used on the at least one other frequency.

53. The computer-program product of claim 52, wherein:

the pilot measurement information identifies a pilot PN spreading code and/or a PN offset used to transmit the pilot signal on the first frequency; and

the computer-readable medium further comprises code for causing the computer to determine the at least one pilot PN spreading code and/or at least one PN offset used on the at least one other frequency based on the identified pilot PN spreading code and/or PN offset.

54. A method of communication, comprising:

maintaining information that associates at least one access point with pilot PN spreading code information used by the at least one access point to transmit pilot signals on a plurality of frequencies;

receiving a first pilot signal on one of the frequencies; and

searching for at least one other pilot signal on at least another one of the frequencies as a result of the receipt of the first pilot signal.

55. The method of claim 54, further comprising:

determining whether the first pilot signal comprises an indication of at least one pilot PN spreading code and/or at least one PN offset listed in the pilot PN spreading code information; and

triggering the search for the at least one other pilot signal based on the determination.

56. The method of claim 54, further comprising:

determining whether the first pilot signal is associated with a femto access point; and

triggering the search for the at least one other pilot signal based on the determination.

57. The method of claim 54, further comprising:

receiving the at least one other pilot signal as a result of the search; and

sending at least one pilot measurement report based on the receptions of the first pilot signal and the at least one other pilot signal.

58. The method of claim 54, wherein the pilot PN spreading code information comprises at least one PN offset or at least one pilot PN spreading code.

59. The method of claim 54, wherein, for each access point of the at least one access point, the maintained information associates the access point with a service frequency used by the access point and at least one beacon frequency used by the access point.

60. The method of claim 54, wherein, for each access point of the at least one access point, the maintained information associates the access point with at least one pilot PN spreading code and/or at least one PN offset, and the information further associates the access point with two or more of the frequencies on which the at least one pilot PN spreading code and/or the at least one PN offset is used.

61. The method of claim 54, wherein the at least one access point comprises at least one femto access point.

62. An apparatus for communication, comprising:

a storage component configured to maintain information that associates at least one access point with pilot PN spreading code information used by the at least one access point to transmit pilot signals on a plurality of frequencies; and

a receiver configured to receive a first pilot signal on one of the frequencies, and further configured to search for at least one other pilot signal on at least another one of the frequencies as a result of the receipt of the first pilot signal.

63. The apparatus of claim 62, further comprising a pilot processor configured to:

determine whether the first pilot signal comprises an indication of at least one pilot PN spreading code and/or at least one PN offset listed in the pilot PN spreading code information; and

trigger the search for the at least one other pilot signal based on the determination.

64. The apparatus of claim 62, further comprising a pilot processor configured to:

determine whether the first pilot signal is associated with a femto access point; and

trigger the search for the at least one other pilot signal based on the determination.

65. The apparatus of claim 62, wherein the pilot PN spreading code information comprises at least one PN offset or at least one pilot PN spreading code.

66. An apparatus for communication, comprising:

means for maintaining information that associates at least one access point with pilot PN spreading code information used by the at least one access point to transmit pilot signals on a plurality of frequencies;

means for receiving a first pilot signal on one of the frequencies; and

means for searching for at least one other pilot signal on at least another one of the frequencies as a result of the receipt of the first pilot signal.

67. The apparatus of claim 66, further comprising:

means for determining whether the first pilot signal comprises an indication of at least one pilot PN spreading code and/or at least one PN offset listed in the pilot PN spreading code information; and

means for triggering the search for the at least one other pilot signal based on the determination.

68. The apparatus of claim 66, further comprising:

means for determining whether the first pilot signal is associated with a femto access point; and

means for triggering the search for the at least one other pilot signal based on the determination.

69. The apparatus of claim 66, wherein the pilot PN spreading code information comprises at least one PN offset or at least one pilot PN spreading code.

70. A computer-program product, comprising:

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

maintain information that associates at least one access point with pilot PN spreading code information used by the at least one access point to transmit pilot signals on a plurality of frequencies;

receive a first pilot signal on one of the frequencies; and

search for at least one other pilot signal on at least another one of the frequencies as a result of the receipt of the first pilot signal.

71. The computer-program product of claim 70, wherein the computer-readable medium further comprises code for causing the computer to:

determine whether the first pilot signal comprises an indication of at least one pilot PN spreading code and/or at least one PN offset listed in the pilot PN spreading code information; and

trigger the search for the at least one other pilot signal based on the determination.

72. The computer-program product of claim 70, wherein the computer-readable medium further comprises code for causing the computer to:

determine whether the first pilot signal is associated with a femto access point; and

trigger the search for the at least one other pilot signal based on the determination.

73. The computer-program product of claim 70, wherein the pilot PN spreading code information comprises at least one PN offset and/or at least one pilot PN spreading code.