Granted Patent B2

US 9,467,965 · App. 14/453,263 · Granted Oct 11, 2016

Abstract

Claims (63)

1. A method, comprising:

clustering entries of positioning data into subsets, each subset defined by a lower boundary of signal strength value and an upper boundary of signal strength value of a plurality of boundaries of signal strength values, each signal strength value indicating a strength of a signal received by a wireless device from a wireless station at a location; and

checking a reset condition that is used to trigger a reset of the boundaries of signal strength values for clustering the entries of positioning data into the subsets, each entry of positioning data associating position information of a location with at least an identifier of a wireless station for providing wireless connection at the location and a signal strength received at the location.

2. The method of claim 1 , further comprising:

updating, when the reset condition is satisfied, one or more of the boundaries of signal strength values to re-allocate the entries of positioning data in the subsets in order to increase a population uniformity across the subsets;

storing the updated boundaries of signal strength values;

selecting a subset of positioning data when a signal strength of a wireless device is within the updated boundaries of signal strength values of the subset in response to a position request to determine position information of the wireless device; and

determining the position information of the wireless device based on the selected subset of positioning data.

3. The method of claim 1 , wherein checking the reset condition that is used to trigger the reset of the boundaries of signal strength values for clustering the entries of positioning data associated with the wireless station into the subsets further comprises at least one of:

comparing a standard deviation of the signal strength values in a subset with a threshold;

comparing a number of positioning data in a subset to a threshold; and

comparing a standard error of sample mean of the signal strength values in a subset to a threshold.

4. The method of claim 1 , further comprising:

updating, when the reset condition is satisfied, one or more of the boundaries of signal strength values to re-allocate the entries of positioning data in the subsets in order to increase a population uniformity across the subsets;

determining a new cumulative distribution function (CDF) value for a subset; and

determining one or two boundaries for the subset to achieve the new CDF.

5. The method of claim 4 , wherein determining the new CDF value for the subset further comprises:

determining the new CDF value for the subset based on CDF values of other subsets and a tolerance.

6. The method of claim 1 , further comprising:

updating, when the reset condition is satisfied, one or more of the boundaries of signal strength values to re-allocate the entries of positioning data in the subsets in order to increase a population uniformity across the subsets;

assigning cumulative distribution function (CDF) values for the subsets; and

determining the boundaries for the subsets to achieve the CDF values across the subsets.

7. The method of claim 6 , wherein assigning the CDF values for the subsets further comprises:

assigning equal CDF values for the subsets.

8. The method of claim 1 , further comprising:

initiating the boundaries of signal strength values of the subsets to evenly divide a space of the signal strength values into the subsets.

9. The method of claim 1 , wherein checking the reset condition that is used to trigger the reset of the boundaries of signal strength values for clustering the entries of positioning data associated the wireless station into subsets further comprises:

adding a plurality of positioning data to the entries of positioning data; and

checking the reset condition after the addition of the plurality of positioning data.

10. The method of claim 2 , wherein storing the updated boundaries of signal strength values further comprises:

storing the updated boundaries of signal strength values for the subsets in a wireless station information table.

11. An apparatus, comprising:

a storage medium configured to provide a database of positioning data, each positioning data associating position information of a location with an identification of a wireless station for providing wireless connection at the location and a strength of a signal received by a wireless device at the location; and

a processor configured to:

cluster entries of positioning data into subsets, each subset defined by a lower boundary of signal strength value and an upper boundary of signal strength value of a plurality of boundaries of signal strength values, each signal strength value indicating the strength of the signal; and

check a reset condition that is used to trigger a reset of the boundaries of signal strength values for clustering the entries of positioning data the subsets.

12. The apparatus of claim 11 , wherein the processor is further configured to:

update, when the reset condition is satisfied, one or more of the boundaries of signal strength values to re-allocate the entries of positioning data in the subsets in order to increase a population uniformity across the subsets;

store the updated boundaries of signal strength values;

select a subset of positioning data when a signal strength of a wireless device is within the updated boundaries of signal strength values of the subset in response to a position request to determine position information of the wireless device; and

determine the position information of the wireless device based on the selected subset of positioning data.

13. The apparatus of claim 11 , wherein the processor is further configured to do at least one of:

comparing a standard deviation of the signal strength values in a subset with a threshold;

comparing a number of positioning data in a subset to a threshold; and

comparing a standard error of sample mean of the signal strength values in a subset to a threshold.

14. The apparatus of claim 11 , wherein the processor is further configured to:

update, when the reset condition is satisfied, one or more of the boundaries of signal strength values to re-allocate the entries of positioning data in the subsets in order to increase a population uniformity across the subsets;

determine a new cumulative distribution function (CDF) value for a subset; and

determine one or two boundaries for the subset to achieve the new CDF.

15. The apparatus of claim 14 , wherein the processor is further configured to

determine the new CDF value for the subset based on CDF values of other subsets and a tolerance.

16. The apparatus of claim 11 , wherein the processor is further configured to:

updating, when the reset condition is satisfied, one or more of the boundaries of signal strength values to re-allocate the entries of positioning data in the subsets in order to increase a population uniformity across the subsets;

assign cumulative distribution function (CDF) values for the subsets; and

determine the boundaries for the subsets to achieve the CDF values across the subsets.

17. The apparatus of claim 16 , wherein the processor is further configured to

assign equal CDF values for the subsets.

18. The apparatus of claim 11 , wherein the processor is further configured to initiate the boundaries of signal strength values of the subsets to evenly divide a space of the signal strength values into the subsets.

19. The apparatus of claim 11 , wherein the processor is further configured to:

add a plurality of positioning data to the entries of positioning data; and

check the reset condition after the addition of the plurality of positioning data.

20. The apparatus of claim 12 , wherein the processor is further configured to

store the updated boundaries of signal strength values for the subsets in a wireless station information table.

Assignments (9)