CONTROLLING ACCESS POINT TRANSMIT POWER BASED ON RECEIVED ACCESS TERMINAL MESSAGES

• US 20120039265A1
• Filed: 02/10/2011
• Published: 02/16/2012
• Est. Priority Date: 02/12/2010
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Patel, Chirag Sureshbhai, Yavuz, Mehmet, Grokop, Leonard Henry, Chande, Vinay, Nanda, Sanjiv, Meshkati, Farhad, Nagaraja, Sumeeth
• Granted Patent: US 8,761,060 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• 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 52/247 where the output power of a terminal is based on a path parameter sent by another terminal
• CPC Class Codes: H04W 52/281 taking into account user or data type priority
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

Transmit power for an access point is controlled based on information received by the access point. For example, an access point may employ one or more algorithms that use messages received from nearby access terminals to maintain an acceptable tradeoff between providing an adequate coverage area for access point transmissions and mitigating interference that these transmissions cause at nearby access terminals. Here, the access point may employ a network listen-based algorithm upon initialization of the access terminal to provide preliminary transmit power control until sufficient information is collected for another transmit power control algorithm (e.g., an access terminal assisted algorithm). Also, the access terminal may employ an active access terminal protection scheme to mitigate interference the access point may otherwise cause to a nearby access terminal that is in active communication with another access point.

Claims

1. A method of communication, comprising:

transmitting data on a forward link, wherein the forward link data is transmitted by an access point on a first carrier frequency;

transmitting beacons on a beacon channel, wherein the beacons are transmitted by the access point on a second carrier frequency;

receiving messages from at least one access terminal at the access point, wherein the messages are indicative of channel quality on the second carrier frequency; and

controlling transmit power of the access point based on the received messages, wherein the transmit power is controlled for transmissions on the first carrier frequency, the second carrier frequency, or the first carrier frequency and the second carrier frequency.

2. The method of claim 1, wherein the controlling of the transmit power based on the received messages only controls beacon transmit power on the second carrier frequency.

3. The method of claim 1, further comprising receiving additional messages from the at least one access terminal at the access point, wherein:

the additional messages are indicative of;

channel quality on the first carrier frequency, at least one path loss between the at least one access terminal and the access point, or channel quality on the first carrier frequency and at least one path loss between the at least one access terminal and the access point; and

the controlling of the transmit power is further based on the received additional messages.

4. The method of claim 1, wherein:

the messages are received over a period of time; and

the controlling of the transmit power based on the received messages comprises adjusting the transmit power upon expiration of the period of time.

5. The method of claim 1, further comprising receiving registration messages at the access point, wherein the controlling of the transmit power is further based on the received registration messages.

6. The method of claim 5, wherein:

the registration messages are received over a period of time; and

the controlling of the transmit power based on the received registration messages comprises adjusting the transmit power upon expiration of the period of time.

7. The method of claim 5, wherein the controlling of the transmit power based on the received registration messages comprises:

classifying an access terminal that sent at least one of the registration messages as a neighboring alien access terminal or a non-neighboring alien access terminal; and

adjusting the transmit power according to different criteria depending on whether the access terminal is classified as a neighboring alien access terminal or a non-neighboring alien access terminal.

8. The method of claim 7, wherein the classification of the access terminal is based on a period of time that the access terminal has camped on the access point.

9. The method of claim 7, wherein the classification of the access terminal is based on a quantity of registration attempts that the access terminal has made at the access point over a period of time.

10. The method of claim 5, wherein:

the controlling of the transmit power based on the received messages comprises establishing transmit power limits based on the channel quality on the second carrier frequency;

the received registration messages correspond to a quantity of registration attempts made by at least one other access terminal over a period of time;

the at least one other access terminal is not authorized to receive active mode service via the access point; and

the controlling of the transmit power based on the received registration messages comprising adjusting the transmit power within the transmit power limits based on the quantity of registration attempts.

11. The method of claim 5, further comprising:

receiving pilot signals from at least one other access point on the second carrier frequency;

identifying channel quality at the access point based on the received pilot signals; and

setting at least one limit for the transmit power based on the identified channel quality.

12. The method of claim 11, further comprising:

determining that another access terminal near the access point is actively receiving information from one of the at least one other access point or another access point on the second carrier frequency; and

restricting transmission by the access point on the second carrier frequency as a result of the determination.

13. The method of claim 1, wherein:

the received messages include information indicative of channel quality at a plurality of locations;

the received messages further include information indicative of path losses between the access point and the plurality of locations;

the controlling of the transmit power comprises setting a minimum transmit power that provides coverage for a subset of the locations; and

the setting of the minimum transmit power is based on;

the path losses corresponding to the subset of locations, the information indicative of the channel quality at the subset of locations, or the path losses corresponding to the subset of locations and the information indicative of the channel quality at the subset of locations.

14. The method of claim 13, wherein:

the information indicative of channel quality comprises pilot signal strengths of pilot signals that the at least one access terminal received from at least one other access point; and

the information indicative of path losses comprises pilot signal strengths of pilot signals that the at least one access terminal received from the access point.

15. The method of claim 1, wherein the controlling of the transmit power comprises specifying first transmit power limits for transmission of low power beacons and specifying second transmit power limits for transmission of high power beacons.

16. The method of claim 1, wherein the received messages comprise pilot strength measurement messages, measurement report messages, or candidate frequency search report messages.

17. The method of claim 1, wherein the at least one access terminal comprises at least one home access terminal for the access point or at least one closed subscriber group access terminal associated with the access point.

18. An apparatus for communication, comprising:

a transmitter operable to transmit data on a forward link and transmit beacons on a beacon channel, wherein the forward link data is transmitted on a first carrier frequency and the beacons are transmitted on a second carrier frequency;

a receiver operable to receive messages from at least one access terminal, wherein the messages are indicative of channel quality on the second carrier frequency; and

a controller operable to control transmit power of the transmitter based on the received messages, wherein the transmit power is controlled for transmissions on the first carrier frequency, the second carrier frequency, or the first carrier frequency and the second carrier frequency.

19. The apparatus of claim 18, wherein the controlling of the transmit power based on the received messages only controls beacon transmit power on the second carrier frequency.

20. The apparatus of claim 18, wherein:

the receiver is further operable to receive additional messages from the at least one access terminal;

the additional messages are indicative of;

channel quality on the first carrier frequency, at least one path loss between the at least one access terminal and the apparatus, or channel quality on the first carrier frequency and at least one path loss between the at least one access terminal and the apparatus; and

the controlling of the transmit power is further based on the received additional messages.

21. The apparatus of claim 18, wherein:

the receiver is further operable to receive registration messages; and

the controlling of the transmit power is further based on the received registration messages.

22. The apparatus of claim 21, wherein the controlling of the transmit power based on the received registration messages comprises:

classifying an access terminal that sent at least one of the registration messages as a neighboring alien access terminal or a non-neighboring alien access terminal; and

adjusting the transmit power according to different criteria depending on whether the access terminal is classified as a neighboring alien access terminal or a non-neighboring alien access terminal.

23. The apparatus of claim 21, wherein:

the controlling of the transmit power based on the received messages comprises establishing transmit power limits based on the channel quality on the second carrier frequency;

the received registration messages correspond to a quantity of registration attempts made by at least one other access terminal over a period of time;

the at least one other access terminal is not authorized to receive active mode service via the apparatus; and

the controlling of the transmit power based on the received registration messages comprising adjusting the transmit power within the transmit power limits based on the quantity of registration attempts.

24. The apparatus of claim 21, wherein:

the receiver is further operable to receive pilot signals from at least one access point on the second carrier frequency;

the controller is further operable to identify channel quality at the apparatus based on the received pilot signals; and

the controller is further operable to set at least one limit for the transmit power based on the identified channel quality.

25. The apparatus of claim 24, wherein the controller is further operable to:

determine that another access terminal near the apparatus is actively receiving information from one of the at least one access point or another access point on the second carrier frequency; and

restrict transmission by the transmitter on the second carrier frequency as a result of the determination.

26. The apparatus of claim 18, wherein:

the received messages include information indicative of channel quality at a plurality of locations;

the received messages further include information indicative of path losses between the apparatus and the plurality of locations;

the controlling of the transmit power comprises setting a minimum transmit power that provides coverage for a subset of the locations; and

the setting of the minimum transmit power is based on;

the path losses corresponding to the subset of locations, the information indicative of the channel quality at the subset of locations, or the path losses corresponding to the subset of locations and the information indicative of the channel quality at the subset of locations.

27. An apparatus for communication, comprising:

means for transmitting data on a forward link and transmitting beacons on a beacon channel, wherein the forward link data is transmitted on a first carrier frequency and the beacons are transmitted on a second carrier frequency;

means for receiving messages from at least one access terminal, wherein the messages are indicative of channel quality on the second carrier frequency; and

means for controlling transmit power of the means for transmitting based on the received messages, wherein the transmit power is controlled for transmissions on the first carrier frequency, the second carrier frequency, or the first carrier frequency and the second carrier frequency.

28. The apparatus of claim 27, wherein the controlling of the transmit power based on the received messages only controls beacon transmit power on the second carrier frequency.

29. The apparatus of claim 27, further comprising means for receiving additional messages from the at least one access terminal, wherein:

the additional messages are indicative of;

channel quality on the first carrier frequency, at least one path loss between the at least one access terminal and the apparatus, or channel quality on the first carrier frequency and at least one path loss between the at least one access terminal and the apparatus; and

the controlling of the transmit power is further based on the received additional messages.

30. The apparatus of claim 27, further comprising means for receiving registration messages, wherein the controlling of the transmit power is further based on the received registration messages.

31. The apparatus of claim 30, wherein the controlling of the transmit power based on the received registration messages comprises:

classifying an access terminal that sent at least one of the registration messages as a neighboring alien access terminal or a non-neighboring alien access terminal; and

adjusting the transmit power according to different criteria depending on whether the access terminal is classified as a neighboring alien access terminal or a non-neighboring alien access terminal.

32. The apparatus of claim 30, wherein:

the controlling of the transmit power based on the received messages comprises establishing transmit power limits based on the channel quality on the second carrier frequency;

the received registration messages correspond to a quantity of registration attempts made by at least one other access terminal over a period of time;

the at least one other access terminal is not authorized to receive active mode service via the apparatus; and

the controlling of the transmit power based on the received registration messages comprising adjusting the transmit power within the transmit power limits based on the quantity of registration attempts.

33. The apparatus of claim 30, further comprising:

means for receiving pilot signals from at least one access point on the second carrier frequency;

means for identifying channel quality at the apparatus based on the received pilot signals; and

means for setting at least one limit for the transmit power based on the identified channel quality.

34. The apparatus of claim 33, further comprising:

means for determining that another access terminal near the apparatus is actively receiving information from one of the at least one access point or another access point on the second carrier frequency; and

means for restricting transmission by the means for transmitting on the second carrier frequency as a result of the determination.

35. The apparatus of claim 27, wherein:

the received messages include information indicative of channel quality at a plurality of locations;

the received messages further include information indicative of path losses between the apparatus and the plurality of locations;

the controlling of the transmit power comprises setting a minimum transmit power that provides coverage for a subset of the locations; and

the setting of the minimum transmit power is based on;

the path losses corresponding to the subset of locations, the information indicative of the channel quality at the subset of locations, or the path losses corresponding to the subset of locations and the information indicative of the channel quality at the subset of locations.

36. A computer-program product, comprising:

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

transmit data on a forward link, wherein the forward link data is transmitted by an access point on a first carrier frequency;

transmit beacons on a beacon channel, wherein the beacons are transmitted by the access point on a second carrier frequency;

receive messages from at least one access terminal at the access point, wherein the messages are indicative of channel quality on the second carrier frequency; and

control transmit power of the access point based on the received messages, wherein the transmit power is controlled for transmissions on the first carrier frequency, the second carrier frequency, or the first carrier frequency and the second carrier frequency.

37. The computer-program product of claim 36, wherein the controlling of the transmit power based on the received messages only controls beacon transmit power on the second carrier frequency.

38. The computer-program product of claim 36, wherein:

the computer-readable medium further comprises code for causing the computer to receive additional messages from the at least one access terminal at the access point;

the additional messages are indicative of;

channel quality on the first carrier frequency, at least one path loss between the at least one access terminal and the access point, or channel quality on the first carrier frequency and at least one path loss between the at least one access terminal and the access point; and

the controlling of the transmit power is further based on the received additional messages.

39. The computer-program product of claim 36, wherein:

the computer-readable medium further comprises code for causing the computer to receive registration messages at the access point; and

the controlling of the transmit power is further based on the received registration messages.

40. The computer-program product of claim 39, wherein the controlling of the transmit power based on the received registration messages comprises:

classifying an access terminal that sent at least one of the registration messages as a neighboring alien access terminal or a non-neighboring alien access terminal; and

adjusting the transmit power according to different criteria depending on whether the access terminal is classified as a neighboring alien access terminal or a non-neighboring alien access terminal.

41. The computer-program product of claim 39, wherein:

the controlling of the transmit power based on the received messages comprises establishing transmit power limits based on the channel quality on the second carrier frequency;

the received registration messages correspond to a quantity of registration attempts made by at least one other access terminal over a period of time;

the at least one other access terminal is not authorized to receive active mode service via the access point; and

the controlling of the transmit power based on the received registration messages comprising adjusting the transmit power within the transmit power limits based on the quantity of registration attempts.

42. The computer-program product of claim 39, wherein the computer-readable medium further comprises code for causing the computer to:

receive pilot signals from at least one other access point on the second carrier frequency;

identify channel quality at the access point based on the received pilot signals; and

set at least one limit for the transmit power based on the identified channel quality.

43. The computer-program product of claim 42, wherein the computer-readable medium further comprises code for causing the computer to:

determine that another access terminal near the access point is actively receiving information from one of the at least one other access point or another access point on the second carrier frequency; and

restrict transmission by the access point on the second carrier frequency as a result of the determination.

44. The computer-program product of claim 36, wherein:

the received messages include information indicative of channel quality at a plurality of locations;

the received messages further include information indicative of path losses between the access point and the plurality of locations;

the controlling of the transmit power comprises setting a minimum transmit power that provides coverage for a subset of the locations; and

the setting of the minimum transmit power is based on;

the path losses corresponding to the subset of locations, the information indicative of the channel quality at the subset of locations, or the path losses corresponding to the subset of locations and the information indicative of the channel quality at the subset of locations.

45. A method of communication, comprising:

transmitting data on a forward link of an access point, wherein the forward link data is transmitted by the access point on a first carrier frequency;

transmitting beacons on a beacon channel, wherein the beacons are transmitted by the access point on a second carrier frequency;

receiving messages from at least one access terminal at the access point, wherein the messages are indicative of;

channel quality on the first carrier frequency, at least one path loss between the at least one access terminal and the access point, or channel quality on the first carrier frequency and at least one path loss between the at least one access terminal and the access point; and

controlling transmit power of the access point based on the received messages, wherein the transmit power is controlled for transmissions on the second carrier frequency.

46. The method of claim 45, wherein the controlling of the transmit power based on the received messages further controls transmit power for transmissions on the first carrier frequency.

47. The method of claim 45, further comprising receiving registration messages at the access point, wherein the controlling of the transmit power is further based on the received registration messages.

48. The method of claim 47, wherein:

the controlling of the transmit power based on the received messages comprises establishing transmit power limits based on the channel quality on the first carrier frequency;

the received registration messages correspond to a quantity of registration attempts made by at least one other access terminal over a period of time;

the at least one other access terminal is not authorized to receive active mode service via the access point; and

the controlling of the transmit power based on the received registration messages comprising adjusting the transmit power within the transmit power limits based on the quantity of registration attempts.

49. The method of claim 48, further comprising:

receiving pilot signals from at least one other access point on the second carrier frequency;

identifying channel quality at the access point based on the received pilot signals; and

setting at least one limit for the transmit power based on the identified channel quality.

50. The method of claim 49, further comprising:

determining that another access terminal near the access point is actively receiving information from one of the at least one other access point or another access point on the second carrier frequency; and

restricting transmission by the access point on the second carrier frequency as a result of the determination.

51. An apparatus for communication, comprising:

a transmitter operable to transmit data on a forward link and transmit beacons on a beacon channel, wherein the forward link data is transmitted on a first carrier frequency and the beacons are transmitted on a second carrier frequency;

a receiver operable to receive messages from at least one access terminal, wherein the messages are indicative of;

channel quality on the first carrier frequency, at least one path loss between the at least one access terminal and the apparatus, or channel quality on the first carrier frequency and at least one path loss between the at least one access terminal and the apparatus; and

a controller operable to control transmit power of the transmitter based on the received messages, wherein the transmit power is controlled for transmissions on the second carrier frequency.

52. The apparatus of claim 51, wherein the controlling of the transmit power based on the received messages further controls transmit power for transmissions on the first carrier frequency.

53. The apparatus of claim 51, wherein:

the receiver is further operable to receive registration messages; and

the controlling of the transmit power is further based on the received registration messages.

54. The apparatus of claim 53, wherein:

the controlling of the transmit power based on the received messages comprises establishing transmit power limits based on the channel quality on the first carrier frequency;

the received registration messages correspond to a quantity of registration attempts made by at least one other access terminal over a period of time;

the at least one other access terminal is not authorized to receive active mode service via the apparatus; and

the controlling of the transmit power based on the received registration messages comprising adjusting the transmit power within the transmit power limits based on the quantity of registration attempts.

55. An apparatus for communication, comprising:

means for transmitting data on a forward link and transmitting beacons on a beacon channel, wherein the forward link data is transmitted on a first carrier frequency and the beacons are transmitted by the access point on a second carrier frequency;

means for receiving messages from at least one access terminal, wherein the messages are indicative of;

channel quality on the first carrier frequency, at least one path loss between the at least one access terminal and the apparatus, or channel quality on the first carrier frequency and at least one path loss between the at least one access terminal and the apparatus; and

means for controlling transmit power of the means for transmitting based on the received messages, wherein the transmit power is controlled for transmissions on the second carrier frequency.

56. The apparatus of claim 55, wherein the controlling of the transmit power based on the received messages further controls transmit power for transmissions on the first carrier frequency.

57. The apparatus of claim 55, further comprising means for receiving registration messages, wherein the controlling of the transmit power is further based on the received registration messages.

58. The apparatus of claim 57, wherein:

the controlling of the transmit power based on the received messages comprises establishing transmit power limits based on the channel quality on the first carrier frequency;

the received registration messages correspond to a quantity of registration attempts made by at least one other access terminal over a period of time;

the at least one other access terminal is not authorized to receive active mode service via the apparatus; and

the controlling of the transmit power based on the received registration messages comprising adjusting the transmit power within the transmit power limits based on the quantity of registration attempts.

59. A computer-program product, comprising:

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

transmit data on a forward link of an access point, wherein the forward link data is transmitted by the access point on a first carrier frequency;

transmit beacons on a beacon channel, wherein the beacons are transmitted by the access point on a second carrier frequency;

receive messages from at least one access terminal at the access point, wherein the messages are indicative of;

channel quality on the first carrier frequency, at least one path loss between the at least one access terminal and the access point, or channel quality on the first carrier frequency and at least one path loss between the at least one access terminal and the access point; and

control transmit power of the access point based on the received messages, wherein the transmit power is controlled for transmissions on the second carrier frequency.

60. The computer-program product of claim 59, wherein the controlling of the transmit power based on the received messages further controls transmit power for transmissions on the first carrier frequency.

61. The computer-program product of claim 59, wherein:

the computer-readable medium further comprises code for causing the computer to receive registration messages at the access point; and

the controlling of the transmit power is further based on the received registration messages.

62. The computer-program product of claim 61, wherein:

the controlling of the transmit power based on the received messages comprises establishing transmit power limits based on the channel quality on the first carrier frequency;

the received registration messages correspond to a quantity of registration attempts made by at least one other access terminal over a period of time;

the at least one other access terminal is not authorized to receive active mode service via the access point; and

the controlling of the transmit power based on the received registration messages comprising adjusting the transmit power within the transmit power limits based on the quantity of registration attempts.