Using broadcast position and transmit power from access points to form assistance data

1. A method in a location server for preparing assistance data,

the method comprising:

computing a crowd-sourced position from a crowd-sourced database for an access point, wherein the crowd-sourced database for the access point comprises ranging information for the access point measured by a plurality of mobile devices and a location of each mobile device in the plurality of mobile devices, wherein the crowd-sourced position is computed based on the ranging information measured by the plurality of mobile devices and the location of each mobile device;

determining that the access point is broadcasting a broadcast position of the access point;

setting a position of the access point based on information of the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point;

saving the position of the access point to an assistance data database.

2. The method of claim 1 , wherein the crowd-sourced position comprises a latitude, longitude and uncertainty.

3. The method of claim 1 , wherein the ranging information measured by the plurality of mobile devices comprises, for each mobile device from the plurality of mobile devices, a path loss between the access point and the mobile device.

4. The method of claim 1 , wherein the ranging information measured by the plurality of mobile devices comprises, for each mobile device from the plurality of mobile devices, a received power or a round trip time measurement.

5. The method of claim 1 , wherein the crowd-sourced database for the access point further comprises the broadcast position from the access point and wherein the crowd-sourced position is determined based on the broadcast position, the location of each mobile device and the ranging information or the path loss value.

6. The method of claim 1 , wherein setting the position of the access point based on information of the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point comprises:

determining an overlap area between an uncertainty area of the crowd-sourced position and an uncertainty area of the broadcast position; and

setting the position of the access point within the overlap area.

7. The method of claim 1 , wherein setting the position of the access point based on information of the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point comprises:

determining an overlap area between an uncertainty area of the crowd-sourced position and an uncertainty area of the broadcast position; and

setting the position of the access point to one of the crowd-sourced position and the broadcast position based on a lower uncertainty.

8. The method of claim 1 , wherein setting the position of the access point based on information of the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point comprises:

determining no overlap area exists between an uncertainty area of the crowd-sourced position and an uncertainty area of the broadcast position; and

setting the position of the access point to the crowd-sourced position.

9. The method of claim 1 , wherein setting the position of the access point based on information of the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point comprises:

calculating a difference between the crowd-sourced position and the broadcast position;

comparing the difference to a threshold to set a position; and

setting the position of the access point based on the comparison.

10. The method of claim 9 , wherein setting the position of the access point based on the comparison comprises:

determining the difference between the crowd-sourced position and the broadcast position is within the threshold; and

selecting the position, between the crowd-sourced position and the broadcast position, having a lower uncertainty.

11. The method of claim 1 , further comprising forming the assistance data from the assistance data database.

12. The method of claim 11 , further comprising sending the assistance data to a mobile device.

13. A location server for preparing assistance data, the location server comprising:

a crowd-sourced database reports for a plurality of access points, wherein the crowd-sourced database for an access point comprises ranging information for the access point measured by a plurality of mobile devices and a location of each mobile device in the plurality of mobile devices;

an assistance data database containing a position of each of the plurality of access points; and

a processor coupled to the crowd-sourced database and the assistance data database, and configured to:

compute a crowd-sourced position from the crowd-sourced database for each access point, wherein the crowd-sourced position is computed based on the ranging information measured by the plurality of mobile devices and the location of each mobile device;

determine that the access point is broadcasting a broadcast position of the access point;

set the position of the access point based on information of the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point;

save the position of the access point to the assistance data database.

14. The location server of claim 13 , further comprising a transceiver, wherein the transceiver is configured to couple to a plurality of mobile devices to receive a coverage report.

15. The location server of claim 13 , wherein the processor is further configured to form the assistance data from the assistance data database.

16. The location server of claim 15 , wherein the processor is further configured to send the assistance data to a mobile device.

17. A location server for preparing assistance data, the location server comprising:

means for computing a crowd-sourced position from a crowd-sourced database for an access point, wherein the crowd-sourced database for the access point comprises ranging information for the access point measured by a plurality of mobile devices and a location of each mobile device in the plurality of mobile devices, wherein the crowd-sourced position is computed based on the ranging information measured by the plurality of mobile devices and the location of each mobile device;

means for determining that the access point is broadcasting a broadcast position of the access point;

means for setting a position of the access point based on information of the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point;

means for saving the position of the access point to an assistance data database.

18. The location server of claim 17 , wherein the means for setting the position of the access point based on information of the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point comprises:

means for determining an overlap area between an uncertainty area of the crowd-sourced position and an uncertainty area of the broadcast position; and

means for setting the position of the access point within the overlap area.

19. The location server of claim 17 , wherein means for setting the position of the access point based on information of the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point comprises:

means for determining an overlap area between an uncertainty area of the crowd-sourced position and an uncertainty area of the broadcast position; and

means for setting the position of the access point to one of the crowd-sourced position and the broadcast position based on a lower uncertainty.

20. The location server of claim 17 , wherein means for setting the position of the access point based on information of the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point comprises:

means for determining no overlap area exists between an uncertainty area of the crowd-sourced position and an uncertainty area of the broadcast position; and

means for setting the position of the access point to the crowd-sourced position.

21. The location server of claim 17 , wherein means for setting the position of the access point based on information of the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point comprises:

means for calculating a difference between the crowd-sourced position and the broadcast position;

means for comparing the difference to a threshold to set a position; and

means for setting the position of the access point based on the comparison.

22. A non-transitory computer-readable storage medium for preparing assistance data in a location server, the non-transitory computer-readable storage medium including program code stored thereon, comprising program code to:

compute a crowd-sourced position from a crowd-sourced database for an access point, wherein the crowd-sourced database for the access point comprises ranging information for the access point measured by a plurality of mobile devices and a location of each mobile device in the plurality of mobile devices, wherein the crowd-sourced position is computed based on the ranging information measured by the plurality of mobile devices and the location of each mobile device;

determine that the access point is broadcasting a broadcast position of the access point;

set a position of the access point based on the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point;

save the position of the access point to an assistance data database.

23. The non-transitory computer-readable storage medium of claim 22 , wherein the program code to set the position of the access point based on the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point comprises program code to set the position to the crowd-sourced position.

24. The non-transitory computer-readable storage medium of claim 22 , wherein the program code to set the position of the access point based on the crowd-sourced position computed by the location server and the broadcast position broadcasted by the access point comprises program code to set the position to the broadcast position.