Signaling-triggered power adjustment in a femto cell

• US 8,126,496 B2
• Filed: 11/20/2008
• Issued: 02/28/2012
• Est. Priority Date: 05/07/2008
• Status: Active Grant

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Inventors: Brisebois, Arthur Richard, Huber, Kurt Donald
• Primary Examiner(s): Pham, Tuan
• Assistant Examiner(s): Wang, Fanghwa
• Application Number:
  US12/275,015
• Publication Number:
  US 20090280853A1
• Time in Patent Office: 1,195 Days
• Field of Search: None
• US Class Current: 455/522
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/28 using user profile, e.g. mobile speed, priority or network state, e.g. standby, idle or non transmission

Abstract

System(s) and method(s) are provided for signaling-triggered power adjustment in a femto cell. Attachment signal activity is measured and a set of derived signaling activity metrics are assessed and compared with a set of thresholds. An activity metric that overcomes an associated threshold results in a power adjustment of the transmission power of a femto access point (AP). By monitoring LAU (location area update), RAU (routing area update), and call activity, signaling activity metrics (e.g., signaling failure rate, access control rejection rate, or dwell time) are determined and a femto AP can optimize transmission power to ensure coverage maintenance and confinement, as well as mitigate unnecessary signaling. Alarm(s) can be conveyed to a femto network platform when power increases after an adjustment cycle; alarm(s) can prompt a network-based response to actively address femto cell operation. Signaling-triggered power management affects operation of AP serving the femto cell and served mobile terminals.

Claims

1. A system that provides signaling-triggered transmission power management in a femto cell access point, the system comprising:

a communication platform configured to receive and measure an attachment signaling activity;

a signaling metric constructor configured to evaluate a signaling activity metric based at least in part on the measured attachment signaling activity and a received network attachment signaling, wherein the signaling activity metric comprises a signaling failure rate that is a function of a ratio of a number of incomplete attachment procedures to a net number of attachment procedures over a specific time interval; and

a power management component configured to adjust transmission power of the femto cell access point in response to the signaling activity metric exceeding a threshold.

2. The system of claim 1, further comprising a monitor component configured to determine confinement coverage performance based on trends derived from observation of power adjustments and signaling activity metrics.

3. The system of claim 2, the signaling metric constructor comprises a timer component configured to facilitate determination of the signaling failure rate.

4. The system of claim 2, wherein the signaling metric constructor is further configured to establish the specific time interval.

5. The system of claim 1, wherein the signaling activity metric further comprises a dwell time that is a time interval between an attach instant of a mobile device to the femto cell access point and a detach instant of the mobile device from the femto cell access point, wherein the attach time comprises a time a femto network grants a request to handover and a macro network hands off first data associated with the mobile device to the femto network, and the detach time comprises a time a macro network grants a handover request and the femto network hands off second data associated with the mobile device to the macro network.

6. The system of claim 1, wherein the power management component comprises an alarm component configured to convey an alarm indication to a femto network platform in response to transmission power of the femto cell access point increasing after a power adjustment in response to the signaling activity metric exceeding the threshold.

7. The system of claim 6, wherein the power management component is further configured to receive a response from the femto network platform to the alarm indication, wherein the response comprises at least one of a directive for the femto cell access point to trigger a self-diagnostic procedure, a directive to restart the femto cell access point, a directive for the femto cell access point to provide a malfunction indicator that is at least one of visual, aural, or physical, or a directive for the femto cell access point to provide a customer service notification to a designated device.

8. The system of claim 1, further comprising a component configured to configure the threshold at a time the femto cell access point is provisioned.

9. The system of claim 1, further comprising a component configured to automatically generate the threshold in accordance to at least one of a schedule or a function of a predetermined number of transmission power adjustments.

10. The system of claim 1, further comprising a component configured to automatically generate the threshold based at least in part on an analysis of historic attachment data.

11. A method for facilitating signaling-triggered transmission power management in a femto cell, the method comprising:

measuring an attachment signaling activity in a femto cell access point;

determining a signaling activity metric based at least in part on the measured attachment signaling activity, wherein the signaling activity metric comprises an access control rejection rate that is a function of a ratio of attachment rejections over attachment attempts over a corresponding time interval; and

adjusting a transmission power of the femto cell access point in response to the signaling activity metric exceeding a threshold.

12. The method of claim 11, further comprising triggering an indication that the signaling activity metric exceeds the threshold.

13. The method of claim 12, further comprising triggering an alarm indication to a femto network in response to the transmission power increasing upon the adjusting the transmission power of the femto cell access point.

14. The method of claim 13, further comprising readjusting the transmission power.

15. The method of claim 14, further comprising receiving a response to the alarm indication from the femto network.

16. The method of claim 15, wherein the femto network response comprises at least one of an indication for the femto cell access point to trigger a self-diagnostic procedure, an indication for the femto cell access point to restart the femto cell access point, an indication for the femto cell access point to provide a malfunction indicator that is at least one of visual, aural, or physical, or an indication for the femto cell access point to provide a customer service notification to a designated device.

17. The method of claim 11, further comprising collecting historic attachment signaling data for the femto cell access point, and analyzing the collected historic attachment signaling data.

18. The method of claim 17, further comprising establishing the threshold based at least in part on the collected historic attachment signaling data.

19. The method of claim 18, further comprising automatically generating the threshold in accordance with at least one of a schedule or a function of a predetermined number of transmission power adjustments.

20. A non-transitory computer-readable medium having instructions stored thereon that, in response to execution, cause at least one computing device to perform operations comprising:

measuring an attachment signaling activity in a femto cell access point;

determining a signaling activity metric based at least in part on the measured attachment signaling activity, wherein the signaling activity metric comprises a dwell time that is a time interval between an attach time of a mobile device to the femto cell access point and a detach time of the mobile device from the femto cell access point, wherein the attach time comprises a time a femto network grants a request to handover and a macro network hands off first data associated with the mobile device to the femto network, and the detach time comprises a time a macro network grants a handover request and the femto network hands off second data associated with the mobile device to the macro network; and

adjusting a transmission power for the femto cell access point in response to the signaling activity metric exceeding a threshold.