Antenna tilt optimization in a wireless communications network

• US 9,473,956 B2
• Filed: 03/03/2014
• Issued: 10/18/2016
• Est. Priority Date: 07/02/2013
• Status: Active Grant

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Inventors: Wellington, Daniel
• Primary Examiner(s): Gelin, Jean
• Application Number:
  US14/195,745
• Publication Number:
  US 20150011227A1
• Time in Patent Office: 960 Days
• Field of Search: 455/446, 455/447, 455/561, 455/562.A, 455/562.1, 455/422.1
• US Class Current: 1/1
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition

Abstract

Optimization of a wireless communications network may be accomplished by collecting information for a plurality of target cells neighboring a source cell, calculating a tilt score based on the collected information, and adjusting an antenna of the source cell based on the tilt score.

Claims

1. A method for adjusting an antenna of a base station in a cellular telecommunications network, the method comprising:

collecting at least one of an activity metric, a transmit power, and an interference value for each of a plurality of target cells neighboring a source cell;

calculating respective first scores for each cell of a portion of the plurality of target cells based on the collected information;

calculating a tilt score based on the first scores;

comparing the tilt score to a predetermined value, and when the tilt score exceeds the predetermined value, adjusting at least one of a tilt angle and a transmission power of an antenna of the source cell based on the tilt score.

2. The method of claim 1, wherein collecting the information for the plurality of target cells comprises:

comparing an activity metric for each cell on a neighbor cell list (NCL) of the source cell to a threshold value; and

when the activity metric exceeds the threshold value, adding the cell associated with the activity metric to a mobility neighbor list,

wherein the portion of the plurality of target cells includes cells of the mobility neighbor list.

3. The method of claim 2, further comprising:

sorting cells on the mobility neighbor list in descending order according to a signal strength value; and

truncating the mobility neighbor list.

4. The method of claim 1, wherein collecting the information for the plurality of target cells comprises:

receiving detected set reports (DSR) at the source cell; and

creating a DSR neighbor list from the received DSRs.

5. The method of claim 4, wherein creating the DSR neighbor list comprises:

comparing an activity metric for each cell on the DSRs to a threshold value; and

when the activity metric exceeds the threshold value, adding the cell associated with the activity metric to the DSR neighbor list.

6. The method of claim 5, wherein creating the DSR neighbor list further comprises:

sorting cells on the DSRs in descending order according to a signal strength value; and

truncating the list of sorted cells.

7. The method of claim 4, wherein creating the DSR neighbor list comprises associating cell identifiers with scrambling codes of the DSR.

8. The method of claim 1, wherein collecting the information for the plurality of target cells comprises:

creating a first neighbor list including a first set of performance metrics; and

creating a second neighbor list including a second set of performance metrics.

9. The method of claim 8, wherein the first neighbor list is a mobility neighbor list, and the second neighbor list is a DSR neighbor list.

10. The method of claim 8, wherein calculating the tilt score includes calculating a first tilt score for the first neighbor list, calculating a second tilt score for the second neighbor list, and adding the first tilt score and the second tilt score.

11. The method of claim 10, further comprising weighting the first tilt score before adding the first tilt score and the second tilt score.

12. The method of claim 1, wherein the collected information includes distance information, signal strength information, and activity information.

13. The method of claim 1, wherein collecting information for the plurality of target cells neighboring a source cell comprises:

determining a set of intra-frequency cells neighboring the source cell;

comparing a metric associated with each cell of the set of source cells to a threshold value; and

when the metric exceeds the threshold value, adding the cell associated with the metric to a list.

14. The method of claim 13, wherein the metric is an activity metric indicating a level of activity with respect to the associated cell.

15. The method of claim 1, wherein adjusting the antenna comprises adjusting one of a transmit power and a tilt angle of the source cell.

16. A wireless communications system comprising:

a processor;

a memory; and

a non-transitory computer readable medium with computer executable instructions stored thereon which, when executed by the processor, perform the following steps;

collecting information for a plurality of target cells neighboring a source cell;

calculating respective first scores for each cell of a portion of the plurality of target cells based on the collected information;

calculating a tilt score based on the first scores; and

comparing the tilt score to a predetermined value, and when the tilt score exceeds the predetermined value, adjusting an antenna of the source cell based on the tilt score.

17. The system of claim 16, wherein collecting the information for the plurality of target cells comprises:

comparing an activity metric for each cell on a neighbor cell list (NCL) of the source cell to a threshold value; and

when the activity metric exceeds the threshold value, adding the cell associated with the activity metric to a mobility neighbor list.

18. The system of claim 17, wherein the non-transitory computer readable medium further comprises instructions for performing steps of:

sorting cells on the mobility neighbor list in descending order according to a signal strength value; and

truncating the mobility neighbor list.

19. The system of claim 16, wherein collecting the information for the plurality of target cells comprises:

receiving detected set reports (DSR) at the source cell; and

creating a DSR neighbor list from the received DSRs.

20. The system of claim 19, wherein creating the DSR neighbor list comprises:

comparing an activity metric for each cell on the DSRs to a threshold value; and

when the activity metric exceeds the threshold value, adding the cell associated with the activity metric to the DSR neighbor list.

21. The system of claim 20, wherein creating the DSR neighbor list further comprises:

sorting cells on the DSRs in descending order according to a signal strength value; and

truncating the list of sorted cells.

22. The system of claim 19, wherein creating the DSR neighbor list comprises associating cell identifiers with scrambling codes of the DSR.

23. The system of claim 16, wherein collecting the information for the plurality of target cells comprises:

creating a first neighbor list including a first set of performance metrics; and

creating a second neighbor list including a second set of performance metrics.

24. The system of claim 23, wherein the first neighbor list is a mobility neighbor list, and the second neighbor list is a DSR neighbor list.

25. The system of claim 23, wherein calculating the tilt score includes calculating a first tilt score for the first neighbor list, calculating a second tilt score for the second neighbor list, and adding the first tilt score and the second tilt score.

26. The system of claim 25, wherein the first tilt score is weighted before adding the first tilt score and the second tilt score.

27. The system of claim 16, wherein the collected information includes distance information, signal strength information, and activity information.

28. The system of claim 16, wherein collecting information for the plurality of target cells neighboring a source cell comprises:

determining a set of intra-frequency cells neighboring the source cell;

comparing a metric associated with each cell of the set of source cells to a threshold value; and

when the metric exceeds the threshold value, adding the cell associated with the metric to a list.

29. The system of claim 28, wherein the metric is an activity metric indicating a level of activity with respect to the associated cell.

30. The system of claim 16, wherein adjusting the antenna comprises adjusting one of a transmit power and a tilt angle of the source cell.

31. The system of claim 16, wherein the tilt score is calculated based on interference metrics, signal strength metrics, and activity metrics for the plurality of target cells.