DYNAMICALLY CONTROLLING A FEMTOCELL BASE STATION DOWNLINK RANGE FOR INTERFERENCE AVOIDANCE

• US 20110105110A1
• Filed: 04/22/2010
• Published: 05/05/2011
• Est. Priority Date: 04/22/2009
• Status: Active Grant

• Current Assignee: Broadcom Semiconductors Israel Limited (Broadcom, Inc.)
• Original Assignee: Percello Ltd. (Broadcom, Inc.)
• Inventors: Carmon, Rafy, Shechter, Alon, Volloch, Yoav, Levy, Sharon
• Granted Patent: US 8,849,336 B2
• Time in Patent Office: Days
• US Class Current: 455/422.1
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/223 predicting future states of the transmission
• 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 52/283 Power depending on the position of the mobile
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

A femtocell power control module is operative to: obtain at least one uplink communication characteristic associated with the uplink signal transmitted by the at least one cellular communication device and received by the femtocell base station; estimate, from the obtained uplink communication characteristic, the power level of the downlink signals transmitted by the femtocell base station, as received by the at least one cellular communication device; if the estimated power level of the downlink signals transmitted by the femtocell base station as received by the at least one cellular communication device exceeds a predefined threshold power level, reduce the power level of the downlink signals transmitted by the femtocell base station to a reduced power level.

Claims

1. In a cellular communication network exhibiting a femtocell base station, at least one neighboring macrocell base station, and at least one cellular communication device camped on the at least one neighboring macrocell base station and barred from camping on the femtocell base station, wherein the at least one cellular communication device transmits uplink signals receivable by the femtocell base station and the at least one neighboring macrocell base station, and wherein the femtocell base station and the at least one neighboring macrocell base station transmit downlink signals receivable by the at least one cellular communication device, and wherein all downlink and uplink signals exhibit power levels, a femtocell power control module operatively associated with the femtocell base station, the femtocell power control module is operative to:

obtain at least one uplink communication characteristic associated with the uplink signals transmitted by the at least one cellular communication device and received by the femtocell base station;

estimate, from the obtained uplink communication characteristic, the power level of the downlink signals transmitted by the femtocell base station, as received by the at least one cellular communication device;

if the estimated power level of the downlink signals transmitted by the femtocell base station as received by the at least one cellular communication device exceeds a predefined threshold power level, reduce the power level of the downlink signals transmitted by the femtocell base station to a reduced power level.

2. The femtocell power control module according to claim 1, wherein the femtocell base station is further operative to:

periodically increase, over a predefined period, the power level of the downlink signals of the femtocell base station to a maximal power level and subsequently decrease the power level of the downlink signals of the femtocell base station to a minimal power level;

wherein if the femtocell power control module reduces the power level of the downlink signals transmitted by the femtocell base station to a reduced power level, the maximal power level is set to said reduced power level.

3. The femtocell power control module according to claim 1, wherein if the femtocell power control module reduces the power level of the downlink signals transmitted by the femtocell base station to a predefined reduced power level, the femtocell power control module is further operative to gradually increase the power level of the downlink signals transmitted by the femtocell base station, over time, from the reduced power level to a power level prior to the reduction, wherein the increase is in accordance with a predefined recovery rate.

4. The femtocell power control module according to claim 2, wherein if the femtocell power control module reduces the power level of the downlink signals transmitted by the femtocell base station to a reduced power level, the femtocell power control module is further operative to gradually increase the power level of the downlink signals transmitted by the femtocell base station, over time, from the reduced power level to the maximal power level, wherein the increase is in accordance with a predefined recovery rate.

5. The femtocell power control module according to claim 1, wherein the cellular communication network further exhibits at least one cellular communication device camped on the femtocell base station, and wherein the reduced power level is selected such that the reduced power level is sufficient to retain communication with the at least one cellular communication device camped on the femtocell base station.

6. The femtocell power control module according to claim 2, wherein the cellular communication network further exhibits at least one cellular communication device camped on the femtocell base station, and wherein the reduced power level is selected such that the reduced power level sufficient to retain communication with the at least one cellular communication device camped on the femtocell base station.

7. The femtocell power control module according to claim 1, wherein the uplink communication characteristic comprise data derived from random access channel (RACH) messages included in the uplink signals transmitted by the at least one cellular communication device, and wherein said data relate to the femtocell base station.

8. The femtocell power control module according to claim 1, wherein the uplink communication characteristic comprises Received Total Wideband Power as measured at the femtocell base station.

9. The femtocell power control module according to claim 1, wherein the cellular communication network further exhibits at least one cellular communication device camped on the femtocell base station, and wherein the uplink communication characteristic comprises Received Total Wideband Power of the at least one cellular communication barred from camping on the femtocell base station and the at least one camped cellular base station, as measured at the femtocell base station.

10. A femtocell base station comprising:

a transceiver; and

a femtocell control module,

wherein the femtocell base station is located within a cellular communication network exhibiting said femtocell base station, at least one neighboring macrocell base station, and at least one cellular communication device camped on the at least one neighboring macrocell base station and further barred from camping on said femtocell base station; and

wherein the at least one cellular communication device transmits uplink signals receivable by the femtocell base station and the at least one neighboring macrocell base station, and wherein the femtocell base station and the at least one neighboring macrocell base station transmit downlink signals receivable by the at least one cellular communication device; and

wherein all downlink and uplink signals exhibit power levels; and

wherein the femtocell control module is operative to obtain at least one uplink communication characteristic associated with the uplink signals transmitted by the at least one cellular communication device and received by the femtocell base station; and

wherein the femtocell control module is further operative to estimate, from the obtained uplink communication characteristic, the power level of the downlink signals transmitted by the femtocell base station, as received by the at least one cellular communication device; and

wherein if the estimated power level of the downlink signals transmitted by the femtocell base station as received by the at least one cellular communication device exceeds a predefined threshold power level, the femtocell control module is operative to reduce the power level of the downlink signals transmitted by the femtocell base station to a reduced power level.

11. The femtocell base station according to claim 10, wherein the femtocell control module is further operative to:

periodically increase, over a predefined period, the power level of the downlink signals of the femtocell base station to a maximal power level and subsequently decrease the power level of the downlink signals of the femtocell base station to a minimal power level;

wherein if the femtocell control module reduces the power level of the downlink signals transmitted by the femtocell base station to a reduced power level, the maximal power level is set to said reduced power level.

12. The femtocell base station according to claim 10, wherein if the femtocell control module reduces the power level of the downlink signals transmitted by the femtocell base station to a predefined reduced power level, the femtocell power control module is further operative to gradually increase the power level of the downlink signals transmitted by the femtocell base station, over time, from the reduced power level to a power level prior to the reduction, wherein the increase is in accordance with a predefined recovery rate.

13. The femtocell base station according to claim 11, wherein if the femtocell control module reduces the power level of the downlink signals transmitted by the femtocell base station to a reduced power level, the femtocell control module is further operative to gradually increase the power level of the downlink signals transmitted by the femtocell base station, over time, from the reduced power level to the maximal power level, wherein the increase is in accordance with a predefined recovery rate.

14. The femtocell base station according to claim 10, wherein the cellular communication network further exhibits at least one cellular communication device camped on the femtocell base station, and wherein the reduced power level is selected such that the reduced power level sufficient to retain communication with the at least one cellular communication device camped on the femtocell base station.

15. The femtocell base station according to claim 11, wherein the cellular communication network further exhibits at least one cellular communication device camped on the femtocell base station, and wherein the reduced power level is selected such that the reduced power level is sufficient to retain communication with the at least one cellular communication device camped on the femtocell base station.

16. The femtocell base station according to claim 10, wherein the uplink communication characteristic comprise data derived from random access channel (RACH) messages included in the uplink signals transmitted by the at least one cellular communication device, and wherein said data relate to the femtocell base station.

17. The femtocell base station according to claim 10, wherein the uplink communication characteristic comprises Received Total Wideband Power as measured at the femtocell base station.

18. The femtocell base station according to claim 10, wherein the cellular communication network further exhibits at least one cellular communication device camped on the femtocell base station, and wherein the uplink communication characteristic comprises Received Total Wideband Power of the at least one cellular communication barred from camping on the femtocell base station and the at least one camped cellular base station, as measured at the femtocell base station.

19. A method for dynamically adjusting power levels of downlink signals of a femtocell base station, the method comprising:

introducing a femtocell base station to a cellular communication network exhibiting at least one neighboring macrocell base station, and at least one cellular communication device camped on the at least one neighboring macrocell base station and barred from camping on said femtocell base station, wherein the at least one cellular communication device transmits uplink signals receivable by the femtocell base station and the at least one neighboring macrocell base station, and wherein the femtocell base station and the at least one neighboring macrocell base station transmit downlink signals receivable by the at least one cellular communication device, and wherein all downlink and uplink signals exhibit power levels;

obtaining at least one uplink communication characteristic associated with the uplink signals transmitted by the at least one cellular communication device and received by the femtocell base station;

estimating, from the obtained uplink communication characteristic, the power level of the downlink signals transmitted by the femtocell base station, as received by the at least one cellular communication device; and

if the estimated power level of the downlink signals transmitted by the femtocell base station as received by the at least one cellular communication device exceeds a predefined threshold power level, reducing the power level of the downlink signals transmitted by the femtocell base station to a reduced power level.

20. The method according to claim 19, further comprising:

periodically increasing, over a predefined period, the power level of the downlink signals of the femtocell base station to a maximal power level and subsequently decreasing the power level of the downlink signals of the femtocell base station to a minimal power level;

wherein if the power level of the downlink signals transmitted by the femtocell base station is reduced to a reduced power level, setting the maximal power level to said reduced power level.

21. The method according to claim 19, wherein if the power level of the downlink signals transmitted by the femtocell base station is reduced to a reduced power level, gradually increasing the power level of the downlink signals transmitted by the femtocell base station, over time, from the reduced power level to a power level prior to the reduction, wherein the increasing is in accordance with a predefined recovery rate.

22. The method according to claim 20, wherein if the power level of the downlink signals transmitted by the femtocell base station is reduced to a reduced power level, gradually increasing the power level of the downlink signals transmitted by the femtocell base station, over time, from the reduced power level to the maximal power level, wherein the increasing is in accordance with a predefined recovery rate.

23. The method according to claim 19, wherein the cellular communication network further exhibits at least one cellular communication device camped on the femtocell base station, and wherein the reduced power level is selected such that the reduced power level is sufficient to retain communication with the at least one cellular communication device camped on the femtocell base station.

24. The method according to claim 20, wherein the cellular communication network further exhibits at least one cellular communication device camped on the femtocell base station, and wherein the reduced power level is selected such that the reduced power level sufficient to retain communication with the at least one cellular communication device camped on the femtocell base station.

25. The method according to claim 19, wherein the uplink communication characteristic comprise data derived from random access channel (RACH) messages included in the uplink signals transmitted by the at least one cellular communication device, and wherein said data relate to the femtocell base station.

26. The method according to claim 19, wherein the uplink communication characteristic comprises Received Total Wideband Power as measured at the femtocell base station.

27. The method according to claim 19, wherein the cellular communication network further exhibits at least one cellular communication device camped on the femtocell base station, and wherein the uplink communication characteristic comprises Received Total Wideband Power of the at least one cellular communication barred from camping on the femtocell base station and the at least one camped cellular base station, as measured at the femtocell base station.