Low power modes for femto cells

• US 8,687,588 B2
• Filed: 06/12/2009
• Issued: 04/01/2014
• Est. Priority Date: 07/02/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Subrahmanya, Parvathanathan
• Primary Examiner(s): Rinehart, Mark
• Assistant Examiner(s): ANWAR, MOHAMMAD S
• Application Number:
  US12/483,652
• Publication Number:
  US 20100002614A1
• Time in Patent Office: 1,754 Days
• Field of Search: 370/331, 370/318, 370/311
• US Class Current: 370/331
• CPC Class Codes: H04W 52/0206 in access points, e.g. base stations access point devices per se H04W88/08
• 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
• CPC Class Codes: H04W 52/322 Power control of broadcast channels
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Devices and methods are provided for deploying and/or implementing a low power mode in an access point (AP) base station. The low power mode may be implemented based on the presence and/or status of access terminals (ATs). In one embodiment, the method may involve determining whether any ATs are present within at least one defined coverage area. In another embodiment, the method may involve determining whether the ATs are in an idle or active state.

Claims

1. A method for facilitating deployment of a low power mode in an access point (AP) base station, comprising:

determining whether any access terminals (ATs) are present within at least one defined coverage area;

in response to no ATs being within the at least one coverage area, entering the low power mode; and

when in the low power mode, varying a transmission power at which the AP base station transmits on a synchronization channel, a pilot signal and a broadcast channel as a function of time, wherein a transmission power level is maintained at a nominal level with adequate frequency to allow new ATs to detect the AP base station and ensure alignment between awake periods of any of the new ATs that become associated with the AP base station.

2. The method of claim 1, wherein determining whether any ATs are present within the at least one coverage area comprises determining whether at least one AT is present within a femto coverage area of the AP base station.

3. The method of claim 1, wherein determining whether any ATs are present within the at least one coverage area comprises receiving mobility data regarding at least one AT as determined by a macro network.

4. The method of claim 1, wherein determining whether any ATs are present within the at least one coverage area comprises receiving information regarding whether at least one AT is present within a macro coverage area of a macro base station of a macro network.

5. The method of claim 1, wherein determining whether any ATs are present within the at least one coverage area comprises receiving a wake-up signal transmitted from a macro network.

6. The method of claim 5, further comprising receiving the wake-up signal based at least in part on identification of at least one of a serving cell and a neighboring cell reported by the at least one AT.

7. The method of claim 5, further comprising receiving the wake-up signal based at least in part on mobility data regarding the at least one AT as determined by the macro network.

8. The method of claim 5, further comprising ceasing to operate in the low power mode in response to receiving the wake-up signal.

9. The method of claim 5, further comprising modifying the transmission power in response to receiving the wake-up signal.

10. The method of claim 9, wherein modifying comprises increasing the transmission power.

11. The method of claim 1, further comprising:

in response to at least one AT being within the at least one coverage area, determining whether each of the at least one AT is an idle state; and

in response to each of the at least one AT being in the idle state, entering a second low power mode.

12. The method of claim 11, further comprising, in response to a given one of the at least one AT being in an awake state, operating in a normal mode.

13. The method of claim 1, wherein determining whether any ATs are present within the at least one coverage area comprises aggregating information regarding at least one AT from a plurality of macro base stations of a macro network.

14. A method for facilitating deployment of a low power mode in an access point (AP) base station, comprising:

determining whether each of at least one access terminal (AT) in at least one defined coverage area is in an idle state;

in response to each of the at least one AT being in the idle state, entering the low power mode; and

when in the low power mode, varying a transmission power at which the AP base station transmits on a synchronization channel, a pilot signal and a broadcast channel as a function of time, wherein a transmission power level is maintained at a nominal level with adequate frequency to allow new ATs to detect the AP base station and ensure alignment between awake periods of associated ATs.

15. The method of claim 14, further comprising, in response to a given one of the at least one AT being in an awake state, operating in a normal mode.

16. A wireless communication device, comprising:

a backhaul interface for a communication backhaul in operative communication with a macro network;

a transceiver module for communicating with at least one of (a) at least one access terminal (AT), (b) the macro network via the backhaul, and (c) at least one base station in operative communication with the macro network;

at least one processor operatively coupled with the backhaul interface and the transceiver module; and

a memory module operatively coupled with the at least one processor and comprising executable code for the at least one processor to;

determine whether any ATs are present within at least one defined coverage area;

in response to no ATs being within the at least one coverage area, place the device in a low power mode; and

when the device is in the low power mode, instruct the transceiver module to vary a transmission power at which the transceiver module transmits on a synchronization channel, a pilot signal and a broadcast channel as a function of time, wherein a transmission power level is maintained at a nominal level with adequate frequency to allow new ATs to detect the base station and ensure alignment between awake periods of any of the new ATs that become associated with the device.

17. The device of claim 16, wherein the at least one coverage area comprises a femto coverage area of an AP base station.

18. The device of claim 16, wherein the at least one processor determines whether any ATs are present within the at least one coverage area by receiving mobility data regarding the at least one AT as determined by the macro network.

19. The device of claim 16, wherein the at least one coverage area comprises a macro coverage area of a macro base station of the macro network.

20. The device of claim 19, wherein the transceiver module receives a wake-up signal transmitted from the macro network.

21. The device of claim 20, wherein the wake-up signal is based at least in part on identification of at least one of a serving cell and a neighboring cell reported by the at least one AT.

22. The device of claim 20, wherein the wake-up signal is based at least in part on mobility data regarding the at least one AT as determined by the macro network.

23. The device of claim 20, wherein the device ceases to operate in the low power mode in response to receiving the wake-up signal.

24. The device of claim 20, wherein the at least one processor instructs the transceiver module to modify the transmission power in response to receiving the wake-up signal.

25. The device of claim 24, wherein the transceiver module increases the transmission power.

26. The device of claim 16, wherein the at least one base station comprises at least one of a macro base station and a neighboring AP base station.

27. The device of claim 16, wherein the at least one processor:

in response to the at least one AT being within the at least one coverage area, determines whether each of the at least one AT is an idle state; and

in response to each of the at least one AT being in the idle state, places the device in a second low power mode.

28. The device of claim 27, wherein the at least one processor, in response to a given one of the at least one AT being in an awake state, places the device in a normal mode.

29. The device of claim 16, wherein the at least one processor determines whether any ATs are present within the at least one coverage area by aggregating information regarding the at least one AT from a plurality of macro base stations of the macro network.

30. A wireless communication device, comprising:

a backhaul interface for a communication backhaul in operative communication with a macro network;

a transceiver module for communicating with at least one of (a) at least one access terminal (AT), (b) the macro network via the backhaul, and (c) at least one base station in operative communication with the macro network;

at least one processor operatively coupled with the backhaul interface and the transceiver module; and

a memory module operatively coupled with the at least one processor and comprising executable code for the at least one processor to;

determine whether each of at least one AT in at least one defined coverage area is an idle state;

in response to each of the at least one AT being in the idle state, place the device in a low power mode; and

when the device is in the low power mode, instruct the transceiver module to vary a transmission power at which the transceiver module transmits on a synchronization channel, a pilot signal and a broadcast channel as a function of time, wherein a transmission power level is maintained at a nominal level with adequate frequency to allow new ATs to detect the base station and ensure alignment between awake periods of associated ATs.

31. The device of claim 30, wherein the at least one processor, in response to a given one of the at least one AT being in an awake state, places the device in a normal mode.

32. A wireless communications apparatus, comprising:

means for determining whether any access terminals (ATs) are present within at least one defined coverage area;

means for entering a low power mode in response to no ATs being within the at least one coverage area; and

means for varying a transmission power at which the apparatus transmits on a synchronization channel, a pilot signal and a broadcast channel as a function of time when in the low power mode, wherein a transmission power level is maintained at a nominal level with adequate frequency to allow new ATs to detect a base station and ensure alignment between awake periods of any of the new ATs that become associated with the base station.

33. The apparatus of claim 32, wherein the at least one coverage area comprises a femto coverage area of an AP base station.

34. A wireless communications apparatus, comprising:

means for determining whether each of at least one access terminal (AT) in at least one defined coverage area is in an idle state;

means for entering a low power mode in response to each of the at least one AT being in the idle state; and

means for varying a transmission power at which the AP base station transmits on a synchronization channel, a pilot signal and a broadcast channel as a function of time when in the low power mode, wherein a transmission power level is maintained at a nominal level with adequate frequency to allow new ATs to detect a base station and ensure alignment between awake periods of associated ATs.

35. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing a computer to determine whether any access terminals (ATs) are present within at least one defined coverage area;

code for causing a computer to, in response to no ATs being within the at least one coverage area, place an access point (AP) base station in a low power mode; and

code for causing a computer to, when the AP base station is in the low power mode, vary a transmission power at which a synchronization channel, a pilot signal and a broadcast channel is transmitted as a function of time, wherein a transmission power level is maintained at a nominal level with adequate frequency to allow new ATs to detect the AP base station and ensure alignment between awake periods of any of the new ATs that become associated with the AP base station.

36. The computer program product comprising a non-transitory computer-readable medium of claim 35, wherein the at least one coverage area comprises a femto coverage area of an AP base station.

37. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing a computer to determine whether each of at least one access terminal (AT) in at least one defined coverage area is in an idle state;

code for causing a computer to place an access point (AP) base station in a low power mode in response to each of the at least one AT being in the idle state; and

code for causing a computer to, when the AP base station is in the low power mode, vary a transmission power at which a synchronization channel, a pilot signal and a broadcast channel is transmitted as a function of time, wherein a transmission power level is maintained at a nominal level with adequate frequency to allow new ATs to detect the AP base station and ensure alignment between awake periods of associated ATs.