Adjusting Wireless Signal Transmission Power

• US 20090163238A1
• Filed: 12/21/2007
• Published: 06/25/2009
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: Bison Patent Licensing, LLC
• Original Assignee: Airvana Corporation (CommScope Holding Company, Inc.)
• Inventors: Rao, Prashanth, Eyuboglu, Vedat, Humblet, Pierre A., Ananthaiyer, Satish
• Granted Patent: US 8,909,278 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 52/225 Calculation of statistics, e.g. average, variance
• CPC Class Codes: H04W 52/241 taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• 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 52/287 when the channel is in stand-by

Abstract

A home base station receives signal to interference and noise ratio data from at least one access terminal, determines whether a transmission power of the home base station should be adjusted based on the received signal to interference and noise ratio data, and then adaptively adjusts the transmission power of the home base station based on the received signal to interference and noise ratio data.

Claims

1. A method comprising:

receiving, at a home base station, signal to interference and noise ratio data from at least one access terminal;

determining whether to adjust a transmission power of the home base station based on the received signal to interference and noise ratio data; and

adaptively adjusting the transmission power of the home base station based on the received signal to interference and noise ratio data.

2. The method of claim 1, wherein the transmission power is beacon transmission power.

3. The method of claim 1, wherein the transmission power is service transmission power.

4. The method of claim 3, wherein the service transmission power is set to a quiescent power level when there is no active connection on the home base station.

5. The method of claim 3, wherein the service transmission power is turned off when no access terminal of the home base station is serviced by a service carrier of the home base station.

6. The method of claim 1, wherein determining whether to adjust transmission power comprises:

building a histogram associated with the at least one access terminal based on the received signal to interference and noise ratio data;

calculating a probability distribution function for the at least one access terminal based upon the histogram;

calculating a coverage failure probability function by computing a weighted sum of probability distribution functions;

calculating a coverage failure complementary cumulative distribution function based upon the weighted sum; and

averaging the coverage failure probability function over a period of time to produce a filtered coverage failure probability; and

determining whether to adjust the transmission power based on the filtered coverage failure probability.

7. The method of claim 6, wherein the transmission power is a service transmission power.

8. The method of claim 7, wherein the service transmission power is reduced.

9. The method of claim 7, wherein the service transmission power is increased.

10. The method of claim 6, wherein the transmission power is a beacon transmission power.

11. The method of claim 10, wherein the signal to interference and noise ratio data is associated with the beacon transmission power and are sent in along with the signal to interference and noise ratio data associated with the service transmission power.

12. The method of claim 10, wherein the signal to interference and noise ratio data is related to the service transmission power, and signal to interference and noise ratio data related to the beacon transmission power are derived from a first report of the signal to interference and noise ratio data related to the service transmission power when the at least one access terminal enters the coverage area of the home base station.

14. The method of claim 10, wherein the signal to interference and noise ratio data are related to the service transmission power, and signal to interference and noise ratio data related to the beacon transmission power derived from at least one report of the signal to interference and noise ratio data related to the service transmission power when the at least one access terminal enters the coverage area of the home base station.

15. The method of claim 6, wherein the weighting is equal among access terminals.

16. The method of claim 6, wherein the weighting depends on profiles of access terminals.

17. The method of claim 6, wherein the weighting depends upon at least one access terminal activity.

18. The method of claim 6, wherein the weighting depends on distances between the home base station and access terminals.

19. The method of claim 18, wherein a probability distribution function of an access terminal located outside the coverage area of the home base station is discounted.

20. The method of claim 4, further comprising:

increasing the service transmission power from the quiescent power level when at least one access terminal becomes active.

21. The method of claim 3, wherein the service transmission power is set between a maximum power level and a minimum power level when the at least one access terminal is active.

22. An apparatus comprising:

a home base station configured to

receive signal to interference and noise ratio data from at least one access terminal,

determine whether a transmission power of the home base station should be adjusted based on the received signal to interference and noise ratio data, and

adaptively adjust the transmission power of the home base station based on the received signal to interference and noise ratio data.

23. The apparatus of claim 22, wherein the transmission power is a service transmission power.

24. The apparatus of claim 22, wherein the transmission power is a beacon transmission power.

25. The apparatus of claim 23, wherein the home base station is further configured to operate in at least one of a normal operating mode and a quiescent power mode, with the home base station operating at a normal operating power level during the normal operating mode and at a quiescent power level during the quiescent power mode, and the transitioning between the normal operating mode and the quiescent power mode being dependent upon the status of at least one access terminal.

26. The apparatus of claim 25, wherein the home base station is further configured to operate in:

a service carrier power off mode in which service transmission power is turned off and initiation of the service carrier power off mode is dependent upon the status of at least one access terminal.

27. The apparatus of claim 26, wherein the home base station switches out of the service carrier power off mode when at least one access terminal acknowledges a service redirection message sent from the home base station.

28. The apparatus of claim 26, wherein the home base station switches into the service carrier power off mode when no access terminal is serviced by the home base station.

29. A computer readable medium storing instructions to cause a home base station to:

receive signal to interference and noise ratio data from at least one access terminal;

determine whether a transmission power of the home base station should be adjusted based on the signal to interference and noise ratio data received; and

adaptively adjust the transmission power of the home base station based on the signal to interference and noise ratio data received.

30. The computer readable medium of claim 29, wherein the transmission power is beacon transmission power.

31. The computer readable medium of claim 29, wherein the transmission power is service transmission power.

32. The computer readable medium of claim 29, wherein determining whether a transmission power of the home base station should be adjusted comprises:

building a histogram for the at least one access terminal based on the signal to interference and noise ratio data received;

calculating a probability distribution function for the at least one access terminal based on the histogram;

constructing a coverage failure probability function by computing a weighted sum of probability distribution functions of all access terminals, and from the weighted sum computing a coverage failure complementary cumulative distribution function;

deriving a filtered coverage failure probability by averaging the coverage failure probability function over a period of time; and

determining whether to adjust the transmission power based on the filtered coverage failure probability.

33. The computer readable medium of claim 31 in which the instructions cause the home base station to turn the service transmission power off when no access terminal is parked at a service carrier of the home base station.

34. The computer readable medium of claim 31 in which the instructions cause the home base station to set the service transmission power to a quiescent power level when all access terminals parked at a service carrier of the home base station are idle.

35. An apparatus comprising:

a portable antenna configured to transmit and receive electromagnetic signals;

a home base station connected to the portable antenna and comprising;

a receiver configured to receive and decode signals from mobile access terminals via the portable antenna in compliance with at least one wireless communication protocol;

a transmitter configured to encode and transmit signals to mobile access terminals via the portable antenna in compliance with at least one wireless communication protocol; and

a power adjusting engine for controlling the transmit power of the home base station, wherein the power adjusting process engine is configured to;

collect signal to interference and noise ratio measurements of at least one access terminal from the receiver;

build a histogram for the at least one access terminal based on the signal to interference and noise ratio data received;

calculate a probability distribution function for the at least one access terminal based on the histogram;

construct a coverage failure probability function by computing a weighted sum of probability distribution functions of all access terminals, and from the weighted sum computing a coverage failure complementary cumulative distribution function;

derive a filtered coverage failure probability by averaging the coverage failure probability function over a period of time;

determine whether to adjust the transmission power based on the filtered coverage failure probability; and

instruct the transmitter to adjust the transmission power of the home base station.