METHOD AND APPARATUS FOR CALIBRATING TRANSMIT POWER OF A FEMTO NODE

• US 20130102309A1
• Filed: 04/19/2012
• Published: 04/25/2013
• Est. Priority Date: 04/21/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: CHANDE, Vinay, Meshkati, Farhad, Goel, Satashu, Zhou, Yan, Yavuz, Mehmet, Nagaraja, Smeeth
• Granted Patent: US 9,456,422 B2
• Time in Patent Office: Days
• US Class Current: 455/435.1
• CPC Class Codes: H04B 17/11 for calibration
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/226 using past references to control power, e.g. look-up-table
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 52/243 taking into account interferences
• CPC Class Codes: H04W 52/244 Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 52/247 where the output power of a terminal is based on a path parameter sent by another terminal
• CPC Class Codes: H04W 52/287 when the channel is in stand-by
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff

Abstract

Methods and apparatuses are provided that include calibrating transmit power of a femto node based on measuring one or more parameters related to usage of the femto node. The femto node can temporarily increase transmit power and analyze received measurement reports to determine a transmit power calibration. The femto node can additionally measure uplink received signal strength indicators over multiple time periods following handover of a user equipment (UE) to determine whether to increase transmit power to cover the UE.

Claims

1. A method for calibrating transmission power of a femto node, comprising:

increasing a transmit power of a femto node from a base transmit power for a duration of time;

receiving one or more measurement reports from one or more user equipments (UEs) during the duration of time; and

calibrating the base transmit power of the femto node based in part on the one or more measurement reports and the increased transmit power.

2. The method of claim 1, further comprising detecting a switch of at least one UE of the one or more UEs served by the femto node from an idle communications mode to an active communications mode, wherein the increasing the transmit power is based on the switch, and the duration of time corresponds to a time the at least one UE is in the active communications mode.

3. The method of claim 2, wherein the increasing the transmit power comprises increasing the transmit power by a fixed value.

4. The method of claim 2, wherein the increasing the transmit power comprises increasing the transmit power by a dynamic value computed based on at least a portion of the one or more measurement reports.

5. The method of claim 4, wherein the dynamic value is computed based on a signal strength measurement of a strongest macro node received by the at least one UE.

6. The method of claim 5, wherein the dynamic value is computed further based on a pathloss edge measurement of the femto node at which handover to the strongest macro node occurs.

7. The method of claim 2, wherein the increasing the transmit power comprises increasing the transmit power by a dynamic value computed based on one or more historical measurement reports received in a previous switch in communications mode by the at least one UE.

8. The method of claim 7, wherein the dynamic value is computed based on a percentile of measurements of a strongest macro node in the one or more historical measurement reports.

9. The method of claim 2, further comprising:

detecting a second switch of the at least one UE from the active communications mode to the idle communications mode; and

decreasing the transmit power to the base transmit power based on the second switch.

10. The method of claim 1, wherein the duration of time correlates to a minimum time for the one or more UEs to attempt registration with the femto node.

11. The method of claim 10, wherein the calibrating the base transmit power is based in part on a pathloss to the femto node and/or one or more macro nodes from the one or more UEs as indicated in the one or more measurement reports.

12. The method of claim 11, wherein the calibrating the base transmit power is based in part on ensuring a level of interference caused by the femto node to at least a portion of the one or more UEs is below a threshold.

13. The method of claim 10, wherein the increasing transmit power is performed periodically until at least one of the one or more UEs is served by the femto node.

14. An apparatus for calibrating transmission power of a femto node, comprising:

at least one processor configured to;

increase a transmit power of a femto node from a base transmit power for a duration of time;

receive one or more measurement reports from one or more user equipments (UEs) during the duration of time; and

calibrate the base transmit power of the femto node based in part on the one or more measurement reports and the increased transmit power; and

a memory coupled to the at least one processor.

15. The apparatus of claim 14, wherein the at least one processor is further configured to detect a switch of at least one UE of the one or more UEs served by the femto node from an idle communications mode to an active communications mode, wherein the at least one processor increases the transmit power based on the switch, and wherein the duration of time corresponds to a time the at least one UE is in the active communications mode.

16. The apparatus of claim 15, wherein the at least one processor increases the transmit power by a fixed value.

17. The apparatus of claim 15, wherein the at least one processor increases the transmit power by a dynamic value computed based on at least a portion of the one or more measurement reports.

18. The apparatus of claim 15, wherein the at least one processor increases the transmit power by a dynamic value computed based on one or more historical measurement reports received in a previous switch in communications mode by the at least one UE.

19. The apparatus of claim 14, wherein the duration of time correlates to a minimum time for the one or more UEs to attempt registration with the femto node.

20. The apparatus of claim 19, wherein the at least one processor calibrates the base transmit power based in part on at least one of a pathloss to the femto node and/or one or more macro nodes from the one or more UEs as indicated in the one or more measurement reports, or ensuring a level of interference caused by the femto node to at least a portion of the one or more UEs is below a threshold.

21. An apparatus for calibrating transmission power of a femto node, comprising:

means for increasing a transmit power of a femto node from a base transmit power for a duration of time;

means for receiving one or more measurement reports from one or more user equipments (UEs) during the duration of time; and

means for calibrating the base transmit power of the femto node based in part on the one or more measurement reports and the increased transmit power.

22. The apparatus of claim 21, further comprising means for detecting a switch of at least one UE of the one or more UEs served by the femto node from an idle communications mode to an active communications mode, wherein the means for increasing increases the transmit power based on the switch, and wherein the duration of time corresponds to a time the at least one UE is in the active communications mode.

23. The apparatus of claim 22, wherein the means for increasing increases the transmit power by a fixed value.

24. The apparatus of claim 22, wherein the means for increasing increases the transmit power by a dynamic value computed based on at least a portion of the one or more measurement reports.

25. The apparatus of claim 22, wherein the means for increasing increases the transmit power by a dynamic value computed based on one or more historical measurement reports received in a previous switch in communications mode by the at least one UE.

26. The apparatus of claim 21, wherein the duration of time correlates to a minimum time for the one or more UEs to attempt registration with the femto node.

27. The apparatus of claim 26, wherein the means for calibrating calibrates the base transmit power based in part on at least one of a pathloss to the femto node and/or one or more macro nodes from the one or more UEs as indicated in the one or more measurement reports, or ensuring a level of interference caused by the femto node to at least a portion of the one or more UEs is below a threshold.

28. A computer program product for calibrating transmit power of a femto node, comprising:

a non-transitory computer-readable medium, comprising;

code for causing at least one computer to increase a transmit power of a femto node from a base transmit power for a duration of time;

code for causing the at least one computer to receive one or more measurement reports from one or more user equipments (UEs) during the duration of time; and

code for causing the at least one computer to calibrate the base transmit power of the femto node based in part on the one or more measurement reports and the increased transmit power.

29. The computer program product of claim 28, wherein the computer-readable medium further comprises code for causing the at least one computer to detect a switch of at least one UE of the one or more UEs served by the femto node from an idle communications mode to an active communications mode, wherein the code for causing the at least one computer to increase increases the transmit power based on the switch, and wherein the duration of time corresponds to a time the at least one UE is in the active communications mode.

30. The computer program product of claim 29, wherein the code for causing the at least one computer to increase increases the transmit power by a fixed value.

31. The computer program product of claim 29, wherein the code for causing the at least one computer to increase increases the transmit power by a dynamic value computed based on at least a portion of the one or more measurement reports.

32. The computer program product of claim 29, wherein the code for causing the at least one computer to increase increases the transmit power by a dynamic value computed based on one or more historical measurement reports received in a previous switch in communications mode by the at least one UE.

33. The computer program product of claim 28, wherein the duration of time correlates to a minimum time for the one or more UEs to attempt registration with the femto node.

34. The computer program product of claim 33, wherein the wherein the code for causing the at least one computer to calibrate calibrates the base transmit power based in part on at least one of a pathloss to the femto node and/or one or more macro nodes from the one or more UEs as indicated in the one or more measurement reports, or ensuring a level of interference caused by the femto node to at least a portion of the one or more UEs is below a threshold.

35. An apparatus for calibrating transmission power of a femto node, comprising:

a power adjusting component for increasing a transmit power of a femto node from a base transmit power for a duration of time;

a measurement report receiving component for receiving one or more measurement reports from one or more user equipments (UEs) during the duration of time; and

a power calibrating component for calibrating the base transmit power of the femto node based in part on the one or more measurement reports and the increased transmit power.

36. The apparatus of claim 35, further comprising a UE mode determining component for detecting a switch of at least one UE of the one or more UEs served by the femto node from an idle communications mode to an active communications mode, wherein the power adjusting component increases the transmit power based on the switch, and wherein the duration of time corresponds to a time the at least one UE is in the active communications mode.

37. The apparatus of claim 36, wherein the power adjusting component increases the transmit power by a fixed value.

38. The apparatus of claim 36, wherein the power adjusting component increases the transmit power by a dynamic value computed based on at least a portion of the one or more measurement reports.

39. The apparatus of claim 38, wherein the dynamic value is computed based on a signal strength measurement of a strongest macro node received by the at least one UE.

40. The apparatus of claim 39, wherein the dynamic value is computed further based on a pathloss edge measurement of the femto node at which handover to the strongest macro node occurs.

41. The apparatus of claim 36, wherein the power adjusting component increases the transmit power by a dynamic value computed based on one or more historical measurement reports received in a previous switch in communications mode by the at least one UE.

42. The apparatus of claim 41, wherein the dynamic value is computed based on a percentile of measurements of a strongest macro node in the one or more historical measurement reports.

43. The apparatus of claim 36, wherein the UE mode determining component detects a second switch of the at least one UE from the active communications mode to the idle communications mode, and the power adjusting component decreases the transmit power to the base transmit power based on the second switch.

44. The apparatus of claim 35, wherein the duration of time correlates to a minimum time for the one or more UEs to attempt registration with the femto node.

45. The apparatus of claim 44, wherein the power calibrating component calibrates the base transmit power based in part on a pathloss to the femto node and/or one or more macro nodes from the one or more UEs as indicated in the one or more measurement reports.

46. The apparatus of claim 45, wherein the power calibrating component calibrates the base transmit power based in part on ensuring a level of interference caused by the femto node to at least a portion of the one or more UEs is below a threshold.

47. The apparatus of claim 44, wherein the power adjusting component increases the transmit power periodically until at least one of the one or more UEs is served by the femto node.

48. A method for calibrating transmit power of a femto node, comprising:

detecting a handover of a served user equipment (UE) from a femto node to another node;

measuring an uplink received signal strength indicator (RSSI) at the femto node over a plurality of time periods based on the detecting the handover; and

calibrating a transmit power of the femto node based on comparing the uplink RSSI measured over the plurality of time periods.

49. The method of claim 48, wherein the plurality of time periods comprise at least an initial time period and a subsequent time period.

50. The method of claim 49, wherein the calibrating the transmit power of the femto node is based on determining that the uplink RSSI at the subsequent time period and the uplink RSSI at the initial time period are within a threshold difference.

51. The method of claim 48, wherein the measured uplink RSSI at each time period of the plurality of time periods corresponds to an average or filtered uplink RSSI value over the time period.

52. An apparatus for calibrating transmit power of a femto node, comprising:

at least one processor configured to;

detect a handover of a served user equipment (UE) from a femto node to another node;

measure an uplink received signal strength indicator (RSSI) at the femto node over a plurality of time periods based on the detecting the handover; and

calibrate a transmit power of the femto node based on comparing the uplink RSSI measured over the plurality of time periods; and

a memory coupled to the at least one processor.

53. The apparatus of claim 52, wherein the plurality of time periods comprise at least an initial time period and a subsequent time period, and wherein the at least one processor calibrates the transmit power of the femto node based on determining that the uplink RSSI at the subsequent time period and the uplink RSSI at the initial time period are within a threshold difference.

54. An apparatus for calibrating transmit power of a femto node, comprising:

means for detecting a handover of a served user equipment (UE) from a femto node to another node;

means for measuring an uplink received signal strength indicator (RSSI) at the femto node over a plurality of time periods based on the detecting the handover; and

means for calibrating a transmit power of the femto node based on comparing the uplink RSSI measured over the plurality of time periods.

55. The apparatus of claim 54, wherein the plurality of time periods comprise at least an initial time period and a subsequent time period, and wherein the means for calibrating calibrates the transmit power of the femto node based on determining that the uplink RSSI at the subsequent time period and the uplink RSSI at the initial time period are within a threshold difference.

56. A computer program product for calibrating transmit power of a femto node, comprising:

a non-transitory computer-readable medium, comprising;

code for causing at least one computer to detect a handover of a served user equipment (UE) from a femto node to another node;

code for causing the at least one computer to measure an uplink received signal strength indicator (RSSI) at the femto node over a plurality of time periods based on the detecting the handover; and

code for causing the at least one computer to calibrate a transmit power of the femto node based on comparing the uplink RSSI measured over the plurality of time periods.

57. The computer program product of claim 56, wherein the plurality of time periods comprise at least an initial time period and a subsequent time period, and wherein the code for causing the at least one computer to calibrate calibrates the transmit power of the femto node based on determining that the uplink RSSI at the subsequent time period and the uplink RSSI at the initial time period are within a threshold difference.

58. An apparatus for calibrating transmit power of a femto node, comprising:

a user equipment (UE) mode determining component for detecting a handover of a served UE from a femto node to another node;

a received signal strength indicator (RSSI) measuring component for measuring an uplink RSSI at the femto node over a plurality of time periods based on the detecting the handover; and

a power calibrating component for calibrating a transmit power of the femto node based on comparing the uplink RSSI measured over the plurality of time periods.

59. The apparatus of claim 58, wherein the plurality of time periods comprise at least an initial time period and a subsequent time period.

60. The apparatus of claim 59, wherein the power calibrating component calibrates the transmit power of the femto node based on determining that the uplink RSSI at the subsequent time period and the uplink RSSI at the initial time period are within a threshold difference.

61. The apparatus of claim 58, wherein the measured uplink RSSI at each time period of the plurality of time periods corresponds to an average or filtered uplink RSSI value over the time period.