Femto cell signaling gating

• US 8,626,223 B2
• Filed: 07/17/2008
• Issued: 01/07/2014
• Est. Priority Date: 05/07/2008
• Status: Expired due to Fees

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.), Microsoft Corporation
• Original Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Inventors: Brisebois, Arthur Richard, Huber, Kurt Donald
• Primary Examiner(s): Magloire, Vladimir
• Application Number:
  US12/175,293
• Publication Number:
  US 20090280819A1
• Time in Patent Office: 2,000 Days
• Field of Search: 455/41.2, 455/69, 455/127.5, 455/435.1, 455/435.2, 455/436, 455/440, 455/444, 455/452.1, 455/453, 455/522, 455/574, 370310-312, 370/318, 370/320, 370/324, 370/328, 370331-333, 370/335, 370/338, 370/491, 370/500
• US Class Current: 455/522
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0078 Timing of allocation
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• 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 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/44 in connection with interruption of transmission
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

System(s) and method(s) are provided to manage signaling in a femto cell access point. A pilot signal power profile, or pilot signal gating, determines transmitted a time-dependent pilot signal power. The power profile displays a duty cycle well below 100% and a power depth, which is the amplitude between maximum and minimum pilot signal power, determined partially upon radio link conditions. The time-dependent power profile can be established through a schedule based at least in part on attachment data or subscriber input; machine-learning method facilitate inferring the schedule. Pilot signal gating profile can be reused in a femto cell deployment to broaden femto cell identification and thus facilitate macro-to-femto handover. Activating/deactivating pilot signal in a femto cell in the scheduled and synchronized manner provided herein leads to macro-femto interference mitigation and mobility improvement(s), and improved battery life of wireless devices that operate in a wireless environment that includes femto cells.

Claims

1. A method, comprising:

verifying a first slope and a second slope are determined to satisfy a defined slope condition that mitigates induced interference conditions in a wireless environment in which a femto cell access point device operates;

gating a pilot signal of the femto cell access point device using profile data defining a time-dependent pilot signal power profile, wherein the gating results in a gated pilot signal and comprises;

increasing a power of the pilot signal as a function of time according to the first slope defined by the time-dependent pilot signal power profile; and

decreasing the power of the pilot signal as a function of time according to the second slope defined by the time-dependent pilot signal power profile; and

conveying the gated pilot signal.

2. The method of claim 1, wherein the gating further comprises:

generating usage schedule data defining usage of the femto cell access point device;

employing the usage schedule data for an update to the time-dependent pilot signal power profile; and

adjusting the power of the pilot signal using the usage schedule data.

3. The method of claim 2, wherein the adjusting the power of the pilot signal comprises:

setting the power of the pilot signal to a first power level;

increasing the power of the pilot signal to a second power level in response to a mobile device being determined to have attached to the femto cell access point device;

storing the power of the pilot signal at the second power level in response to the mobile device being determined to have remained attached; and

resetting the power of the pilot signal to the first power level in response to the mobile device being determined to have detached from the femto cell access point device.

4. The method of claim 3, wherein the time-dependent pilot signal power profile is periodic with a duty cycle below 100%.

5. The method of claim 4, wherein the time-dependent pilot signal power profile comprises power depth data determined using a channel quality condition, wherein the power depth data represents a difference a first defined signal power and a second defined signal power.

6. The method of claim 1, further comprising verifying the first slope and the second slope are determined to satisfy another defined slope condition that enables a defined level of pilot signal gating for the femto access point device, wherein the induced interference conditions in which the femto access point device operates relate to interference with another network induced by a femto network that comprises the femto access point device.

7. The method of claim 2, wherein the generating the usage schedule further comprises:

tracking event data representing attachment events of a set of subscriber stations to the femto cell access point devices;

determining profile data representing attachment of a subscribers station of the set of subscriber stations to the femto cell access point device using the attachment events; and

generating the usage schedule using the profile data.

8. The method of claim 7, wherein the determining the profile data comprises employing machine-learning to determine the profile data.

9. The method of claim 1, further comprising determining plan data representing a plan to reuse pilot signal gating profiles for a set of femto cell access point devices.

10. The method of claim 9, wherein the set of femto cell access point devices is a first set of femto cell access point devices, and further comprising:

identifying a second set of femto cell access points that share a cell identification report data representing channel conditions for a set of femto cell devices corresponding to the second set of femto cell access points;

refining the second set of femto cell access point devices resulting in a refined set of femto cell access point devices;

identifying a femto cell access point device in the refined set of femto cell access point device to serve a subscriber station for which a transfer from a macro network device to the femto cell access point device is requested; and

facilitating the transfer requested for the subscriber station and the femto cell access point device.

11. The method of claim 10, wherein the identifying the femto cell access point in the refined set of femto cell access point devices comprises identifying the femto cell access point device using access data representing a set of authorized mobile devices.

12. A system, comprising:

a processor that facilitates execution of instructions stored in a memory to perform operations, comprising;

tracking attachment events from a macro cell device to a femto cell device;

generating a schedule for gating a pilot signal of a femto cell device using the attachment events;

increasing a power of the pilot signal according to a first slope defined by the schedule;

decreasing the power of the pilot signal according to a second slope defined by the schedule;

verifying the first slope and the second slope satisfy a defined slope function defined to mitigate induced interference conditions in a wireless environment in which the femto cell device operates; and

a transmitter, configured to transmit a pilot signal power profile of the femto cell device using the schedule.

13. The system of claim 12, wherein the operations further comprise:

determining a profile of attachment to the femto cell device using the attachment events; and

identifying a pattern associated with the attachment events,

wherein the schedule is generated based on the profile of attachment or the pattern.

14. The system of claim 13, wherein the schedule is further generated based on a femto cell identification reuse distance that relates to a distance between a first femto cell access point device and a second femto cell access point device.

15. The system of claim 14, wherein the profile of attachment is determined using machine-learning.

16. The system of claim 15, wherein the operations further comprise identifying the pattern based on the machine-learning.

17. The system of claim 16, wherein the machine-learning comprises applying a neural network.

18. The system of claim 12, wherein the operations further comprise:

scheduling a power of the transmitter to a first pilot signal power level in response to a first subscriber station being determined to have attached to the femto cell device; and

lowering the power of the transmitter to a second pilot signal power level in response to a last subscriber station being determined to have detached from the femto cell device.

19. The system of claim 12, wherein the operations further comprise facilitating an update to the schedule for the femto cell device.

20. The system of claim 12, wherein the pilot signal power profile is a time-dependent power profile that has a power depth determined based on a channel quality condition, wherein the power depth represents a difference between a defined maximum signal power and a defined minimum signal power.

21. The system of claim 20, wherein the time-dependent power profile is periodic with a duty cycle below 100%.

22. The system of claim 12, wherein the induced interference conditions relate to interference conditions induced by a network in which the femto cell device operates on a second network.

23. The system of claim 19, further comprising copying the schedule to a storage medium associated with a different femto cell device that differs from the femto cell device.

24. The system of claim 23, wherein the operations further comprise generating a plan to reuse the schedule in connection with other femto cell devices that share a common identifier with the femto cell device.

25. The system of claim 24, wherein the plan is generated based on a configuration deployment of of the other femto cell devices with the common identifier.

26. The system of claim 25, wherein the operations further comprise:

identifying the other femto cell devices that share the common identifier based on a radio link condition for a set of femto radio access network devices;

utilizing the plan to refine membership of the other femto cell devices resulting in a refined set of femto cell devices;

identifying a serving femto cell device in the refined set of femto cell devices to serve a wireless device that requests a transfer from a macro network device to a femto cell network device; and

resolving a handover associated with the transfer between the wireless device and the serving femto cell device.

27. The system of claim 26, wherein an identification of the serving femto cell device in the refined set of femto cell devices is based on access data representing authorized mobile devices.

28. A non-transitory computer-readable storage medium comprising instructions stored thereon that, in response to execution, cause a system comprising a processor to perform operations, comprising:

gating a pilot signal of a femto cell access point device according at least in part to a time-dependent pilot signal power profile, wherein the gating results in a gated pilot signal and comprises;

instructing a transmitter to ramp-up a power of the pilot signal according to a first slope described in the time-dependent pilot signal power profile; and

instructing the transmitter to ramp-down the power of the pilot signal according to a second slope described in the time-dependent pilot signal power profile;

verifying the first slope and the second slope satisfy a defined slope condition that mitigates induced interference conditions in a wireless environment in which the femto cell access point device operates; and

conveying the gated pilot signal.

29. The non-transitory computer-readable storage medium of claim 28, wherein the gating the pilot signal of a femto cell access point device based at least part on the time-dependent pilot signal power profile further comprises:

generating a usage schedule representing a usage of the femto cell access point device;

utilizing the usage schedule for adjusting the time-dependent pilot signal power profile; and

adjusting the power of the pilot signal according to the usage schedule.

30. The non-transitory computer-readable storage medium of claim 29, wherein the generating the usage schedule further comprises:

tracking attachment events associated with a set of subscriber stations that register to the femto cell access point device;

determining a profile of attachment based on the attachment events; and

wherein the generating the usage schedule is based on the profile of attachment.

31. The non-transitory computer-readable storage medium of claim 30, wherein the determining the profile of attachment is based at least in part on machine-learning.

32. The non-transitory computer-readable storage medium of claim 30, the operations further comprising:

establishing a plan to reuse the usage schedule in connection with a set of femto cell access point devices;

identifying a subset of the set of femto cell access point devices that share a cell identification based at least in part on a received channel conditions report for the subset of femto cell access point devices;

utilizing the plan to identify a refined set of femto cell access point devices that is a subset of the set of femto cell access point devices;

identifying a serving femto cell access point device from the refined set of femto cell access point devices to serve a subscriber station that requests a transfer from a macro network device to a femto network device; and

establishing a connection between the subscriber station and the serving femto cell access point device.