Intra-frequency cell reselection restriction in wireless communications

• US 8,285,285 B2
• Filed: 03/31/2009
• Issued: 10/09/2012
• Est. Priority Date: 08/08/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kitazoe, Masato, Prakash, Rajat, Tenny, Nathan E., Horn, Gavin B., Agashe, Parag A.
• Primary Examiner(s): Hu, Jinsong
• Assistant Examiner(s): Chang, Jean
• Application Number:
  US12/415,820
• Publication Number:
  US 20100035615A1
• Time in Patent Office: 1,288 Days
• Field of Search: 455/436, 455/434, 455/458, 455/456.1, 455/410, 370/332, 370/328
• US Class Current: 455/436
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/20 for optimising the interference level
• CPC Class Codes: H04W 48/02 Access restriction performed under specific conditions

Abstract

Systems and methodologies are described that facilitate utilizing reselection indicators in reselecting access points in wireless communications. In particular, an indicator can be provided relating to a restricted association access point that specifies whether intra-frequency reselection is allowed. If so, a mobile device receiving the indicator can reselect to other access points, to which it has access, operating in a similar frequency. If not, the mobile device can evaluate access points in other frequencies so as not to cause substantial interference to the restricted association access point. In addition, a predicted level of interference caused by communicating with an intra-frequency access point can be computed and evaluated to override the reselection indicator, in some cases. Thus, a restricted association access point can control reselection for some devices to mitigate interference while allowing the devices to override prohibitive restricted access points.

Claims

1. A method, comprising:

receiving a reselection indicator related to a restricted association access point that specifies whether intra-frequency reselection is allowed;

receiving an offset related to predicting interference caused to the restricted association access point by communicating with a target access point that operates in a similar frequency region as the restricted association access point; and

determining whether to select the target access point based on the reselection indicator and the offset, wherein the reselection indicator is overridden where a predicted level of interference resulting from communicating with the target access point is below a threshold level.

2. The method of claim 1, further comprising ranking one or more access points, including the restricted association access point and the target access point wherein the restricted association access point ranked higher than the target access point.

3. The method of claim 1, further comprising computing the predicted level of interference resulting from communicating with the target access point.

4. The method of claim 3, wherein computing the predicted level of interference includes comparing a reference signal received power (RSRP) of the restricted association access point to that of the target access point added to the offset.

5. The method of claim 4, further comprising computing a disparate predicted level of interference related to a lower ranked target access point where the predicted level of interference resulting from communication with the target access point exceeds the threshold level for overriding the reselection indicator.

6. The method of claim 5, further comprising evaluating access points on a disparate frequency or technology for reselection based at least in part on determining that the disparate predicted level of interference is beyond the threshold level for overriding the reselection indicator.

7. The method of claim 1, further comprising initializing a timer upon receiving the reselection indicator wherein the reselection indicator specifies that intra-frequency reselection is not allowed.

8. The method of claim 7, further comprising:

reading a second reselection indicator upon expiry of the timer; and

determining whether to select the target access point based on the second reselection indicator and the offset.

9. The method of claim 1, wherein the reselection indicator is received from a macrocell base station that provides a sector in which the restricted association access point is located.

10. The method of claim 9, wherein the reselection indicator applies to substantially all restricted association access points located within the sector.

11. The method of claim 9, wherein the reselection indicator is received along with additional system information of the sector.

12. The method of claim 1, wherein the reselection indicator is received from the restricted association access point.

13. A wireless communications apparatus, comprising:

at least one processor configured to;

obtain a reselection indicator related to a restricted association access point that specifies whether intra-frequency access point reselection is allowed;

receive an offset related to potential interference caused from communicating with a target access point that operates in a similar frequency region as the restricted association access point; and

determine whether to select the target access point based at least in part on the reselection indicator and the offset, wherein the reselection indicator is overridden where a predicted level of interference resulting from communicating with the target access point is below a threshold level; and

a memory coupled to the at least one processor.

14. The wireless communications apparatus of claim 13, wherein the at least one processor is further configured to rank access points for reselection where the restricted association access point is ranked higher than the target access point.

15. The wireless communications apparatus of claim 13, wherein the at least one processor is further configured to compute the predicted level of interference to the restricted association access point resulting from communicating with the target access point and the at least one processor determines whether to select the target access point further based at least in part on the predicted level of interference.

16. The wireless communications apparatus of claim 15, wherein the at least one processor computes the predicted level of interference at least in part by comparing a reference signal received power (RSRP) of the restricted association access point to that of the target access point added to the offset.

17. The wireless communications apparatus of claim 16, wherein the at least one processor is further configured to compute a disparate predicted level of interference related to a lower ranked target access point where the predicted level of interference resulting from communication with the target access point exceeds the threshold level for overriding the reselection indicator.

18. The wireless communications apparatus of claim 17, wherein the at least one processor is further configured to analyze access points on a disparate frequency or technology for reselection based at least in part on determining that the disparate predicted level of interference is beyond the threshold level for overriding the reselection indicator.

19. The wireless communications apparatus of claim 13, wherein the at least one processor is further configured to initialize a timer upon obtaining the reselection indicator wherein the reselection indicator specifies that intra-frequency reselection is not allowed.

20. The wireless communications apparatus of claim 19, wherein the at least one processor is further configured to receive a disparate reselection indicator related to the restricted association access point upon expiration of the timer.

21. The wireless communications apparatus of claim 13, wherein the at least one processor obtains the reselection indicator from a macrocell base station that provides a sector within which the restricted association access point is located.

22. The wireless communications apparatus of claim 21, wherein the reselection indicator applies to substantially all restricted association access points located within the sector.

23. An apparatus, comprising:

means for receiving a reselection indicator related to a restricted association access point that specifies whether intra-frequency reselection is allowed;

means for obtaining an offset related to potential interference caused from communicating with a target access point that operates in a similar frequency region as the restricted association access point; and

means for determining whether to select the target access point based at least in part on the reselection indicator and the offset, wherein the reselection indicator is overridden where a predicted level of interference resulting from communicating with the target access point is below a threshold level.

24. The apparatus of claim 23, further comprising means for ranking a plurality of access points for reselection, including the restricted association access point and the target access point, based at least in part on reference signal strength wherein the restricted association access point is ranked higher than the target access point.

25. The apparatus of claim 23, further comprising means for estimating the predicted level of interference to the restricted association access point resulting from communicating with the target access point wherein the means for determining determines whether to select the target access point further based at least in part on the predicted level of interference.

26. The apparatus of claim 25, wherein the means for estimating the predicted level of interference compares a reference signal received power (RSRP) of the restricted association access point to that of the target access point added to the offset.

27. The apparatus of claim 26, wherein the means for estimating further estimates a disparate predicted level of interference related to a lower ranked target access point where the predicted level of interference resulting from communication with the target access point exceeds the threshold level for overriding the reselection indicator.

28. The apparatus of claim 27, wherein the means for determining whether to select the target access point evaluates access points on a disparate frequency or technology for reselection based at least in part on determining that the disparate predicted level of interference is beyond the threshold level for overriding the reselection indicator.

29. The apparatus of claim 23, further comprising means for initializing a timer upon obtaining the reselection indicator wherein the reselection indicator specifies that intra-frequency reselection is not allowed.

30. The apparatus of claim 29, wherein the means for receiving the reselection indicator further receives a disparate reselection indicator related to the restricted association access point upon expiry of the timer.

31. The apparatus of claim 23, wherein the means for receiving receives the reselection indicator from a macrocell base station that provides a sector within which the restricted association access point is located.

32. The apparatus of claim 31, wherein the reselection indicator relates to substantially all restricted association access points located within the sector.

33. A computer program product embodied on a non-transitory computer-readable medium comprising:

code for causing at least one computer to receive a reselection indicator related to a restricted association access point that specifies whether intra-frequency reselection is allowed;

code for causing the at least one computer to receive an offset related to predicting interference caused to the restricted association access point by communicating with a target access point that operates in a similar frequency region as the restricted association access point; and

code for causing the at least one computer to determine whether to select the target access point based on the reselection indicator and the offset, wherein the reselection indicator is overridden where a predicted level of interference resulting from communicating with the target access point is below a threshold level.

34. The computer program product of claim 33, wherein the computer-readable medium further comprises code for causing the at least one computer to rank one or more access points, including the restricted association access point and the target access point wherein the restricted association access point is ranked higher than the target access point.

35. The computer program product of claim 33, wherein the computer-readable medium further comprises code for causing the at least one computer to compute the predicted level of interference resulting from communicating with the target access point wherein determining whether to select the target access point is further based at least in part on computing the predicted level of interference.

36. The computer program product of claim 35, wherein the code for causing the at least one computer to compute the predicted level of interference includes comparing a reference signal received power (RSRP) of the restricted association access point to that of the target access point added to the offset.

37. The computer program product of claim 36, wherein the computer-readable medium further comprises code for causing the at least one computer to compute a disparate predicted level of interference related to a lower ranked target access point where the predicted level of interference resulting from communication with the target access point exceeds the threshold level of overriding the reselection indicator.

38. The computer program product of claim 37, wherein the computer-readable medium further comprises code for causing the at least one computer to evaluate access points on a disparate frequency or technology for reselection based at least in part on determining that the disparate predicted level of interference is beyond the threshold level for overriding the reselection indicator.

39. The computer program product of claim 33, wherein the computer-readable medium further comprises code for causing the at least one computer to initialize a timer upon receiving the reselection indicator wherein the reselection indicator specifies that intra-frequency reselection is not allowed.

40. The computer program product of claim 39, wherein the code for causing the at least one computer to receive the reselection indicator further receives a disparate reselection indicator related to the restricted association access point upon expiry of the timer.

41. The computer program product of claim 33, wherein the computer-readable medium further comprises code for causing the at least one computer to receive the reselection indicator from a macrocell base station that provides a sector in which the restricted association access point is located.

42. The computer program product of claim 41, wherein the reselection indicator applies to substantially all restricted association access points located within the sector.

43. A wireless device, comprising:

a reselection indicator receiving component that obtains a reselection indicator related to a restricted association access point that specifies whether intra-frequency reselection is allowed;

an interference prediction component that receives an offset related to interference caused by communicating with a target access point that operates in a similar frequency range as the restricted association access point; and

an access point reselection component that determines whether to select a target access point based at least in part on the reselection indicator and the offset, wherein the reselection indicator is overridden where a predicted level of interference resulting from communicating with the target access point is below a threshold level.

44. The wireless device of claim 43, further comprising an access point measuring component that ranks a plurality of access points of reselection, including the restricted association access point and the target access point, based at least in part on reference signal strength wherein the restricted association access point is ranked higher than the target access point.

45. The wireless device of claim 43, further comprising an interference prediction component that estimates the predicted level of interference to the restricted association access point resulting from communicating with the target access point wherein the access point reselection component determines whether to select the target access point further based at least in part on the predicted level of interference.

46. The wireless device of claim 45, wherein the interference prediction component further compares a reference signal received power (RSRP) of the restricted association access point to that of the target access point added to the offset.

47. The wireless device of claim 46, wherein the interference prediction component further estimates a disparate predicted level of interference related to a lower ranked target access point where the predicted level of interference resulting from communication with the target access point exceeds the threshold level for overriding the reselection indicator.

48. The wireless device of claim 47, wherein the access point reselection component evaluates access points on a disparate frequency or technology for reselection based at least in part on determining that the disparate predicted level of interference is beyond the threshold level for overriding the reselection indicator.

49. The wireless device of claim 43, further comprising a timer component that initializes a timer upon obtaining the reselection indicator wherein the reselection indicator specifies that intra-frequency reselection is not allowed.

50. The wireless device of claim 49, wherein the reselection indicator receiving component further receives a disparate reselection indicator related to the restricted association access point upon expiry of the timer.

51. The wireless device of claim 43, wherein the reselection indicator receiving component receives the reselection indicator from a macrocell base station that provides a sector within which the restricted association access point is located.

52. The wireless device of claim 51, wherein the reselection indicator relates to substantially all restricted association access points located within the sector.

53. A method, comprising:

communicating with an access point to facilitate accessing a wireless network;

evaluating a reselection indicator related to a restricted association access point in the wireless network that specifies whether intra-frequency reselection is allowed; and

analyzing disparate access points in a disparate frequency for reselection based at least in part on the reselection indicator, wherein analyzing access points in the disparate frequency for reselection is further based at least in part on computing an estimated level of interference to the restricted association access point resulting from communicating with the access point, and wherein the reselection indicator is overridden where the estimated level of interference is below a threshold level.

54. The method of claim 53, wherein computing the estimated level of interference includes comparing a reference signal received power (RSRP) of the restricted association access point to that of the access point based on a negative offset.

55. The method of claim 54, further comprising receiving the negative offset from the access point.

56. A wireless communications apparatus, comprising:

at least one processor configured to;

receive wireless network access from an access point;

evaluate a reselection indicator related to a restricted association access point in the wireless network that specifies whether intra-frequency reselection is allowed; and

analyze disparate access points in a disparate frequency for reselection based at least in part on the reselection indicator, wherein the at least one processor is further configured to compute an estimated level of interference to the restricted association access point resulting from communicating with the access point wherein the at least one processor analyzes access points in the disparate frequency for reselection further based at least in part on the estimated level of interference, and wherein the reselection indicator is overridden where the estimated level of interference is below a threshold level; and

a memory coupled to the at least one processor.

57. The wireless communications apparatus of claim 56, wherein that at least one processor computes the estimated level of interference based on comparing a reference signal received power (RSRP) of the restricted association access point to that of the access point subtracting an offset.

58. The wireless communications apparatus of claim 57, wherein the at least one processor is further configured to receive the offset from the access point.

59. An apparatus, comprising:

means for communicating with an access point to facilitate accessing a wireless network;

means for receiving a reselection indicator related to a restricted association access point in the wireless network that specifies whether intra-frequency reselection is allowed;

means for analyzing disparate access points in a disparate frequency or technology for reselection based at least in part on the reselection indicator; and

means for computing an estimated level of interference to the restricted association access point resulting from communicating with the access point, wherein the means for analyzing disparate access points analyzes access points in the disparate frequency for reselection further based at least in part on the estimated level of interference, and wherein the reselection indicator is overridden where the estimated level of interference is below a threshold level.

60. The apparatus of claim 59, wherein the means for computing the estimated level of interference computes based at least in part on comparing a reference signal received power (RSRP) of the restricted association access point to that of the access point adding a negative offset.

61. The apparatus of claim 60, wherein the means for computing the estimated level of interference receives the negative offset from the access point.

62. A computer program product embodied on a non-transitory computer-readable medium comprising:

code for causing at least one computer to communicate with an access point to facilitate accessing a wireless network;

code for causing the at least one computer to evaluate a reselection indicator related to a restricted association access point in the wireless network that specifies whether intra-frequency reselection is allowed; and

code for causing the at least one computer to analyze disparate access points in a disparate frequency for reselection based at least in part on the reselection indicator, wherein analyzing access points in the disparate frequency for reselection is further based at least in part on computing an estimated level of interference to the restricted association access point resulting from communicating with the access point, and wherein the reselection indicator is overridden where the estimated level of interference is below a threshold level.

63. The computer program product of claim 62, wherein computing the estimated level of interference includes comparing a reference signal received power (RSRP) of the restricted association access point to that of the access point based on a negative offset.

64. The computer program product of claim 63, wherein the computer-readable medium further comprises code for causing the at least one computer to receive the negative offset from the access point.

65. A wireless device, comprising:

a reselection indicator receiving component that receives a reselection indicator related to a restricted association access point in the wireless network that specifies whether intra-frequency reselection is allowed;

an access point reselection component that evaluates disparate access points in a disparate frequency or technology for reselection from a current access point based at least in part on the reselection indicator; and

an interference prediction component that estimates a level of interference to the restricted association access point resulting from communicating with the current access point, wherein the access point reselection component evaluates access points in the disparate frequency for reselection further based at least in part on the estimated level of interference, and wherein the reselection indicator is overridden where the estimated level of interference is below a threshold level.

66. The wireless device of claim 65, wherein the interference prediction component estimates the level of interference based at least in part on comparing a reference signal received power (RSRP) of the restricted association access point to that of the access point adding a negative offset.

67. The wireless device of claim 66, wherein the interference predication component receives the negative offset from the access point.

68. A method, comprising:

providing one or more sectors selectable by one or more mobile devices for receiving access to a wireless network;

generating a reselection indicator based at least in part on factoring previous interference from disparate mobile devices communicating with intra-frequency access points within the one or more sectors; and

transmitting the reselection indicator to one or more mobile devices in the one or more sectors that specifies whether intra-frequency reselection is allowed for disparate access points in the one or more sectors.

69. The method of claim 68, further comprising transmitting a closed subscriber group (CSG) identifier to the one or more mobile devices in the one or more sectors to indicate restricted association.

70. The method of claim 68, wherein the reselection indicator relates to one or more restricted association access points located in the one or more sectors.

71. The method of claim 68, further comprising receiving a request for the reselection indicator.

72. The method of claim 68, further comprising receiving the reselection indicator from an underlying wireless network.

73. A wireless communications apparatus, comprising:

at least one processor configured to;

implement one or more sectors selectable by one or more mobile devices for receiving access to a wireless network;

generate a reselection indicator based at least in part on factoring previous interference from disparate mobile devices communicating with intra-frequency access points within the one or more sectors; and

provide the reselection indicator to one or more mobile devices in the one or more sectors that specifies whether intra-frequency reselection is allowed for disparate access points in the one or more sectors; and

a memory coupled to the at least one processor.

74. The wireless communications apparatus of claim 73, wherein the at least one processor is further configured to provide a closed subscriber group (CSG) identifier to the one or more mobile devices in the one or more sectors to indicate restricted association.

75. The wireless communications apparatus of claim 73, wherein the reselection indicator relates to one or more restricted association access points located in the one or more sectors.

76. The wireless communications apparatus of claim 73, wherein the at least one processor is further configured to receive a request for the reselection indicator from the one or more mobile devices.

77. The wireless communications apparatus of claim 73, wherein the at least one processor is further configured to receive the reselection indicator from an underlying wireless network.

78. An apparatus, comprising:

means for communicating with one or more mobile devices in a provided sector to provide access to a wireless network;

means for generating a reselection indicator based at least in part on factoring previous interference from disparate mobile devices communicating with intra-frequency access points within the provided sector; and

means for transmitting the reselection indicator to the one or more mobile devices that specifies whether intra-frequency reselection is allowed for disparate access points in the one or more sectors.

79. The apparatus of claim 78, further comprising means for providing a closed subscriber group (CSG) identifier to the one or more mobile devices in the provided sector to indicate restricted association.

80. The apparatus of claim 78, wherein the reselection indicator relates to one or more restricted association access points located in the provided sector.

81. The apparatus of claim 78, wherein the means for transmitting the reselection indicator receives a request for the reselection indicator from the one or more mobile devices.

82. The apparatus of claim 78, wherein the means for transmitting the reselection indicator receives the reselection indicator from an underlying wireless network.

83. A computer program product embodied on a non-transitory computer-readable medium comprising:

code for causing at least one computer to provide one or more sectors selectable by one or more mobile devices for receiving access to a wireless network;

code for causing the at least one computer to generate a reselection indicator based at least in part on factoring previous interference from disparate mobile devices communicating with intra-frequency access points within the one or more sectors; and

code for causing the at least one computer to transmit the reselection indicator to one or more mobile devices in the one or more sectors that specifies whether intra-frequency reselection is allowed for disparate access points in the one or more sectors.

84. The computer program product of claim 83, wherein the computer-readable medium further comprises code for causing the at least one computer to transmit a closed subscriber group (CSG) identifier to the one or more mobile devices in the one or more sectors to indicate restricted association.

85. The computer program product of claim 83, wherein the reselection indicator relates to one or more restricted association access points located in the one or more sectors.

86. The computer program product of claim 83, wherein the computer-readable medium further comprises code for causing the at least one computer to receive a request for the reselection indicator.

87. The computer program product of claim 83, wherein the computer-readable medium further comprises code for causing the at least one computer to receive the reselection indicator from an underlying wireless network.

88. A wireless device, comprising:

a transmitter for communicating with one or more mobile devices in a provided sector to provide access to a wireless network; and

a reselection indicator component that provides a reselection indicator to the one or more mobile devices specifying whether intra-frequency reselection is allowed for disparate access points in the one or more sectors, wherein the reselection indicator component generates the reselection indicator based at least in part on factoring previous interference from disparate mobile devices communicating with intra-frequency access points within the provided sector.

89. The wireless device of claim 88, further comprising a restricted association component that provides a closed subscriber group (CSG) identifier to the one or more mobile devices in the provided sector to indicate restricted association.

90. The wireless device of claim 88, wherein the reselection indicator relates to one or more restricted association access points located in the provided sector.

91. The wireless device of claim 88, wherein the reselection indicator component receives a request for the reselection indicator from the one or more mobile devices.

92. The wireless device of claim 88, wherein the reselection indicator component receives the reselection indicator from an underlying wireless network.

93. A method, comprising:

providing one or more sectors selectable by one or more mobile devices for receiving access to a wireless network; and

transmitting an offset to a mobile device relating to overriding a reselection indicator received from a restricted association access point that specifies whether intra-frequency reselection is allowed, wherein the offset further relates to predicting interference caused to the restricted association access point by the mobile device communicating with a target access point that operates in a similar frequency region as the restricted association access point, and wherein the reselection indicator is overridden where a predicted level of interference resulting from the mobile device communicating with the target access point is below a threshold level.

94. The method of claim 93, further comprising providing wireless network access to the mobile device wherein the offset is a negative offset.

95. A wireless communications apparatus, comprising:

at least one processor configured to;

implement one or more sectors selectable by one or more mobile devices for receiving access to a wireless network; and

provide an offset to a mobile device relating to overriding a reselection indicator received from a restricted association access point that specifies whether intra-frequency reselection is allowed, wherein the offset further relates to predicting interference caused to the restricted association access point by the mobile device communicating with a target access point that operates in a similar frequency region as the restricted association access point, and wherein the reselection indicator is overridden where a predicted level of interference resulting from the mobile device communicating with the target access point is below a threshold level; and

a memory coupled to the at least one processor.

96. The wireless communications apparatus of claim 95, wherein the at least one processor is further configured to provide wireless network access to the mobile device wherein the offset is a negative offset.

97. An apparatus, comprising:

means for communicating with one or more mobile devices in a wireless network; and

means for transmitting an offset to a mobile device relating to overriding a reselection indicator received from a restricted association access point that specifies whether intra-frequency reselection is allowed, wherein the offset further relates to predicting interference caused to the restricted association access point by the mobile device communicating with a target access point that operates in a similar frequency region as the restricted association access point, and wherein the reselection indicator is overridden where a predicted level of interference resulting from the mobile device communicating with the target access point is below a threshold level.

98. The apparatus of claim 97, wherein the means for communicating provides wireless network access to the mobile device wherein the offset is a negative offset.

99. A computer program product embodied on a non-transitory computer-readable medium comprising:

code for causing at least one computer to provide one or more sectors selectable by one or more mobile devices for receiving access to a wireless network; and

code for causing at least one computer to transmit an offset to a mobile device relating to overriding a reselection indicator received from a restricted association access point that specifies whether intra-frequency reselection is allowed, wherein the offset further relates to predicting interference caused to the restricted association access point by the mobile device communicating with a target access point that operates in a similar frequency region as the restricted association access point, and wherein the reselection indicator is overridden where a predicted level of interference resulting from the mobile device communicating with the target access point is below a threshold level.

100. The computer program product of claim 99, wherein the computer-readable medium further comprises code for causing the at least one computer to provide wireless network access to the mobile device wherein the offset is a negative offset.

101. A wireless device, comprising:

a transmitter for communicating with one or more mobile devices in a wireless network; and

an interference offset component that transmits an offset to a mobile device relating to overriding a reselection indicator received from a restricted association access point that specifies whether intra-frequency reselection is allowed, wherein the offset further relates to predicting interference caused to the restricted association access point by the mobile device communicating with a target access point that operates in a similar frequency region as the restricted association access point, and wherein the reselection indicator is overridden where a predicted level of interference resulting from the mobile device communicating with the target access point is below a threshold level.

102. The wireless device of claim 101, wherein the wireless device provides wireless network access to the mobile device wherein the offset is a negative offset.