Wireless handoffs between multiple networks

• US 8,275,377 B2
• Filed: 10/05/2006
• Issued: 09/25/2012
• Est. Priority Date: 04/20/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Nanda, Sanjiv, Meylan, Arnaud, Deshpande, Manoj M., Jayaram, Ranjith
• Primary Examiner(s): Cai, Wayne
• Assistant Examiner(s): PHAM, TIMOTHY X
• Application Number:
  US11/539,059
• Publication Number:
  US 20070249291A1
• Time in Patent Office: 2,182 Days
• Field of Search: 455/436, 455/73
• US Class Current: 455/436
• CPC Class Codes: H04W 36/00224 between packet switched [PS] and circuit switched [CS] network technologies, e.g. circuit switched fallback [CSFB]
• CPC Class Codes: H04W 36/00835 Determination of neighbour cell lists
• CPC Class Codes: H04W 36/008357 Determination of target cell based on access point [AP] properties, e.g. AP service capabilities
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/22 for handling the traffic
• CPC Class Codes: H04W 48/20 Selecting an access point

Abstract

The disclosure is directed to an access terminal, and method for selecting an access point for handing off the access terminal. The access terminal may include a processor. The processor may be configured to access a list access points and select one of the access points on the list based on the current traffic state of the access terminal.

Claims

1. An access terminal, comprising:

a processor configured to access a first list of access points and select one of the access points on the first list based on a current traffic state of the access terminal, wherein the first list includes indicators for one or more of the access points on the first list that indicate whether an access point is able to support the current traffic state, wherein the processor is further configured to access a second list comprising additional information regarding at least one of the access points on the first list, wherein the access points in the second list have previously served the access terminal, the processor being further configured to update the first list based on the additional information in the second list.

2. The access terminal of claim 1, wherein the processor is further configured to maintain a database in the access terminal, the database comprising the first list of access points.

3. The access terminal of claim 1, wherein the additional information relates to whether the access terminal is able to associate with the selected one of the access points.

4. The access terminal of claim 1, wherein the additional information relates to a quality of service provided by the selected one of the access points to the access terminal.

5. The access terminal of claim 4, wherein the quality of service includes delay, jitter, packet loss rate, or time taken to associate with the selected one of the access points.

6. The access terminal of claim 4, wherein the quality of service includes dropped frames.

7. The access terminal of claim 5, wherein the quality of service includes dropped frames between the access terminal and a far end connection.

8. The access terminal of claim 1, wherein the processor is further configured to maintain the indicators from the additional information in the second list, the selection of said one of the access points also being based on the indicators.

9. The access terminal of claim 8, wherein the indicators for each of one or more access points comprise a data session handoff flag and a voice call handoff flag, and wherein the updating the first list comprises controlling the state of the indicators based on the additional information in the second list.

10. The access terminal of claim 8, wherein the additional information in the second list includes historical information relating to a quality of service provided to the access terminal by one or more access points that have previously served the access terminal.

11. The access terminal of claim 8, wherein the additional information in the second list identifies the access points that belong to the same subnet served by the same dynamic host configuration protocol (DHCP).

12. The access terminal of claim 8, wherein the additional information in the second list identifies access points that belong to the same authentication domain.

13. The access terminal of claim 1, wherein the processor is further configured to handoff the access terminal from a serving access point in a first network to the selected one of the access points, the selected one of the access points being in a second network.

14. The access terminal of claim 1, wherein the processor is further configured to handoff the access terminal from a serving access point in a network to the selected one of the access points, the selected one of the access points being in the same network as the serving access point.

15. The access terminal of claim 1, wherein the processor is further configured to select one of the access points on the first list by performing a periodic scan having an interval that depends on the current traffic state of the access terminal.

16. The access terminal of claim 1, wherein the selection of said one of the selected access points by processor is also based on real time measurements of the access points on the first list.

17. The access terminal of claim 16, wherein the real time measurements include received power from the access points, loading on the access points, and interference on a channel of each of the access points.

18. The access terminal of claim 1, wherein the processor is further configured to access a third list of access points that the access terminal is prohibited from associating with, the selection of said one of the access points also being based on the third list.

19. The access terminal of claim 1, wherein the processor is further configured to access a list of preferred access points, the selection of said one of the access points also being based on the list of preferred access points.

20. The access terminal of claim 1, wherein the access points on the first list are from a wireless local area network (WLAN) and a cellular network, and wherein the processor is further configured to select said one of the access points by searching for access points in the WLAN before searching for access points in the cellular network when the access terminal is in a data session.

21. The access terminal of claim 1, wherein the access points on the first list are from a wireless local area network (WLAN) and a cellular network, and wherein the processor is further configured to select said one of the access points by searching for access points in the cellular network before searching for access points in the WLAN when the access terminal is in a voice call.

22. A method of communications on an access terminal, comprising:

employing a processor to execute computer readable instructions stored on a computer readable medium to perform the following acts;

accessing a first list of access points;

selecting one of the access points on the first list based on a current traffic state of the access terminal, wherein the first list includes indicators for one or more of the access points on the first list that indicate whether an access point is able to support the current traffic state;

accessing a second list comprising additional information regarding at least one of the access points on the first list, wherein the access points in the second list have previously served the access terminal; and

updating the first list based on the additional information in the second list.

23. The method of claim 22, further comprising maintaining a database in the access terminal, the database comprising the first list of access points.

24. The method of claim 22, wherein the additional information relates to whether the access terminal is able to associate with the selected one of the access points.

25. The method of claim 22, wherein the additional information relates to a quality of service provided by the selected one of the access points to the access terminal.

26. The method of claim 25, wherein the quality of service includes delay, jitter, packet loss rate, or time taken to associate with the selected one of the access points.

27. The method of claim 25, wherein the quality of service includes dropped frames.

28. The method of claim 27, wherein the quality of service includes dropped frames between the access terminal and a far end connection.

29. The method of claim 22, further comprising maintaining the indicators from the additional information in the second list, the selection of said one of the access points also being based on the indicators.

30. The method of claim 29, wherein the indicators for each of one or more access points indicates whether the access point is a handoff candidate for each traffic state, wherein the updating the first list comprises controlling the state of the indicators based on the additional information in the second list.

31. The method of claim 29, wherein the additional information in the second list includes historical information relating to a quality of service provided to the access terminal by one or more access points that have previously served the access terminal.

32. The method of claim 29, wherein the additional information in the second list identifies the access points that belong to the same subnet served by the same dynamic host configuration protocol (DHCP).

33. The method of claim 29, wherein the additional information in the second list identifies access points that belong to the same authentication domain.

34. The method of claim 22, further comprising handing off the access terminal from a serving access point in a first network to the selected one of the access points, the selected one of the access points being in a second network.

35. The method of claim 22, further comprising handing off the access terminal from a serving access point in a network to the selected one of the access points, the selected one of the access points being in the same network as the serving access point.

36. The method of claim 22, wherein the selection of said one of the access points comprising performing a periodic scan having an interval that depends on the current traffic state of the access terminal.

37. The method of claim 22, wherein the selection of said one of the selected access points is also based on real time measurements of the access points on the first list.

38. The method of claim 37, wherein the real time measurements include received power from the access points, loading on the access points, and interference on a channel of each of the access points.

39. The method of claim 22, further comprising accessing a third list of access points that the access terminal is prohibited from associating with, the selection of said one of the access points also being based on the third list.

40. The method of claim 22, further comprising accessing a list of preferred access points, the selection of said one of the access points also being based on the list of preferred access points.

41. The method of claim 22, wherein the access points on the first list are from a wireless local area network (WLAN) and a cellular network, and wherein the selection of said one of the access points comprises searching for access points in the WLAN before searching for access points in the cellular network when the access terminal is in a data session.

42. The method of claim 22, wherein the access points on the first list are from a wireless local area network (WLAN) and a cellular network, and wherein the selection of said one of the access points comprises searching for access points in the cellular network before searching for access points in the WLAN when the access terminal is in a voice call.

43. An access terminal, comprising:

means for accessing a first list of access points;

means for selecting one of the access points on the first list based on a current traffic state of the access terminal, wherein the first list includes indicators for one or more of the access points on the first list that indicate whether an access point is able to support the current traffic state;

means for accessing a second list comprising additional information regarding at least one of the access points on the first list, wherein the access points in the second list have previously served the access terminal; and

means for updating the first list based on the additional information in the second list.

44. The access terminal of claim 43, further comprising means for maintaining a database in the access terminal, the database comprising the first list of access points.

45. The access terminal of claim 43, wherein the additional information relates to whether the access terminal is able to associate with the selected one of the access points.

46. The access terminal of claim 43, wherein the additional information relates to a quality of service provided by the selected one of the access points to the access terminal.

47. The access terminal of claim 46, wherein the quality of service includes delay, jitter, packet loss rate, or time taken to associate with the selected one of the access points.

48. The access terminal of claim 46, wherein the quality of service includes dropped frames.

49. The access terminal of claim 48, wherein the quality of service includes dropped frames between the access terminal and a far end connection.

50. The access terminal of claim 43, further comprising means for maintaining the indicators from the additional information in the second list, and wherein the means for selecting one of the access points on the first list is configured to use the indicators to select said one of the access points.

51. The access terminal of claim 50, wherein the indicators for each of one or more access points indicates whether the access point is a handoff candidate for each traffic state, wherein the means for updating the first list comprise means for controlling the state of the indicators based on the additional information in the second list.

52. The access terminal of claim 50, wherein the additional information in the second list includes historical information relating to a quality of service provided to the access terminal by one or more access points that have previously served the access terminal.

53. The access terminal of claim 50, wherein the additional information in the second list identifies the access points that belong to the same subnet served by the same dynamic host configuration protocol (DHCP).

54. The access terminal of claim 50, wherein the additional information in the second list identifies access points that belong to the same authentication domain.

55. The access terminal of claim 43, further comprising means for handing off the access terminal from a serving access point in a first network to the selected one of the access points, the selected one of the access points being in a second network.

56. The access terminal of claim 43, further comprising handing off the access terminal from a serving access point in a network to the selected one of the access points, the selected one of the access points being in the same network as the serving access point.

57. The access terminal of claim 43, wherein the means for selecting one of the access points further comprises means for performing a periodic scan having an interval that depends on the current traffic state of the access terminal.

58. The access terminal of claim 43, wherein the means for selecting one of the access points is configured to use real time measurements to select said one of the access points.

59. The access terminal of claim 58, wherein the real time measurements include received power from the access points, loading on the access points, and interference on a channel of each of the access points.

60. The access terminal of claim 43, further comprising means for accessing a third list of access points that the access terminal is prohibited from associating with, wherein the means for selecting one of the access points is configured to use the third list to select said one of the access points.

61. The access terminal of claim 43, further comprising means for accessing a list of preferred access points, wherein the means for selecting one of the access points is configured to use the list of preferred access points to select said one of the access points.

62. The access terminal of claim 43, wherein the access points on the first list are from a wireless local area network (WLAN) and a cellular network, and wherein the means for selecting one of the access points is configured to search for access points in the WLAN before searching for access points in the cellular network when the access terminal is in a data session.

63. The access terminal of claim 43, wherein the access points on the first list are from a wireless local area network (WLAN) and a cellular network, and wherein the means for selecting one of the access points is configured to search for access points in the cellular network before searching for access points in the WLAN when the access terminal is in a voice call.

64. A non-transitory computer-readable medium including instructions stored thereon, comprising:

a first instruction set for accessing a first list of access points;

a second instruction set for selecting one of the access points on the first list based on a current traffic state of the access terminal, wherein the first list includes indicators for one or more of the access points on the first list that indicate whether an access point is able to support the current traffic state;

a third instruction set for accessing a second list comprising additional information regarding at least one of the access points on the first list, wherein the access points in the second list have previously served the access terminal; and

a fourth instruction set for updating the first list based on the additional information in the second list.

65. The computer-readable medium of claim 64, further comprising a fifth instruction set for maintaining a database in the access terminal, the database comprising the first list of access points.

66. The computer-readable medium of claim 64, wherein the additional information relates to whether the access terminal is able to associate with the selected one of the access points.

67. The computer-readable medium of claim 64, wherein the additional information relates to a quality of service provided by the selected one of the access points to the access terminal.

68. The computer-readable medium of claim 67, wherein the quality of service includes delay, jitter, packet loss rate, or time taken to associate with the selected one of the access points.

69. The computer-readable medium of claim 67, wherein the quality of service includes dropped frames.

70. The computer-readable medium of claim 69, wherein the quality of service includes dropped frames between the access terminal and a far end connection.

71. The computer-readable medium of claim 64, further comprising a fifth instruction set for maintaining the indicators from the additional information in the second list, and wherein the second instruction set is configured to use the indicators to select said one of the access points.

72. The computer-readable medium of claim 71, wherein the indicators for each of one or more access points indicates whether the access point is a handoff candidate for each traffic state, wherein the fourth instruction set updates the first list by controlling the state of the indicators based on the additional information in the second list.

73. The computer-readable medium of claim 71, wherein the additional information in the second list includes historical information relating to a quality of service provided to the access terminal by one or more access points that have previously served the access terminal.

74. The computer-readable medium of claim 71, wherein the additional information in the second list identifies the access points that belong to the same subnet served by the same dynamic host configuration protocol (DHCP).

75. The computer-readable medium of claim 71, wherein the additional information in the second list identifies access points that belong to the same authentication domain.

76. The computer-readable medium of claim 64, further comprising a fifth instruction set for handing off the access terminal from a serving access point in a first network to the selected one of the access points, the selected one of the access points being in a second network.

77. The computer-readable medium of claim 64, further comprising a fifth instruction set for handing off the access terminal from a serving access point in a network to the selected one of the access points, the selected one of the access points being in the same network as the serving access point.

78. The computer-readable medium of claim 64, wherein the second instruction set is configured to perform a periodic scan having an interval that depends on the current traffic state of the access terminal.

79. The computer-readable medium of claim 64, wherein the second instruction set is configured to use real time measurements to select said one of the access points.

80. The computer-readable medium of claim 79, wherein the real time measurements include received power from the access points, loading on the access points, and interference on a channel of each of the access points.

81. The computer-readable medium of claim 64, further comprising a fifth instruction set for accessing a third list of access points that the access terminal is prohibited from associating with, wherein the second instruction set is configured to use the third list to select said one of the access points.

82. The computer-readable medium of claim 64, further comprising a fifth instruction set for accessing a list of preferred access points, wherein the second instruction set is configured to use the list of preferred access points to select said one of the access points.

83. The computer-readable medium of claim 64, wherein the access points on the first list are from a wireless local area network (WLAN) and a cellular network, and wherein the second instruction set is configured to search for access points in the WLAN before searching for access points in the cellular network when the access terminal is in a data session.

84. The computer-readable medium of claim 64, wherein the access points on the first list are from a wireless local area network (WLAN) and a cellular network, and wherein the second instruction set is configured to search for access points in the cellular network before searching for access points in the WLAN when the access terminal is in a voice call.