Techniques for reducing scans for indoor position determination

Abstract

Techniques for determining the position of a mobile device using almanac data are provided as are techniques for providing almanac data to the mobile device from a location server. The almanac data can be provided to the mobile device based on coarse location information provided by the mobile device. The almanac data can include information Media Access Control (MAC) addresses of one or more wireless access points and most recently used channel identification. The almanac data can also be binned by location by the location server and a subset of the almanac data can be selected to be provided to the mobile device based on the coarse location of the mobile device and on positioning effectiveness criteria associated with the wireless access points included in the almanac data.

What is claimed is: 
     
         1 . A method for determining a position of a mobile device, comprising:
 measuring signals from a plurality of wireless access points;   determining the position of the mobile device based at least in part on the signals measured;   identifying a subset of wireless access points from the plurality of wireless access points from which the mobile device was able to measure the signals;   identifying active channels associated with the subset of wireless access points on which the subset of wireless access points were transmitting at a time that the signals were measured; and   sending identifiers associated with the subset of wireless access points and active channels to a location server.   
     
     
         2 . The method of  claim 1  further comprising:
 sending a request to one or more wireless access points to scan for other wireless access points; and 
 receiving one or more scan reports from the one or more wireless access points, wherein measuring signals from the plurality of wireless access points includes measuring signals from the one or more wireless access points included in the one or more scan reports. 
 
     
     
         3 . The method of  claim 2  wherein the request includes an indication of one or more channels to be scanned by the one or more wireless access points. 
     
     
         4 . The method of  claim 2  wherein the request includes an indication of a scan type to be performed by the one or more wireless access points. 
     
     
         5 . The method of  claim 1  wherein measuring signals from the plurality of wireless access points includes determining a set of proximate wireless access points and measuring signals from the set of proximate wireless access points. 
     
     
         6 . The method of  claim 1  wherein measuring signals from the plurality of wireless access points includes selecting a set of wireless access points operating on a same channel and measuring signals from the set of wireless access points. 
     
     
         7 . The method of  claim 1  wherein determining the position of the mobile device based at least in part on the signals measured includes sending one or more signal measurements to the location server and receiving the position of the mobile device from the location server. 
     
     
         8 . The method of  claim 1  further comprising performing a scan for wireless access points proximate to the mobile device. 
     
     
         9 . A method for providing position assistance data to a mobile device, comprising:
 receiving identifiers and active channels associated with a plurality of wireless access points, wherein an active channel indicates a channel on which a respective wireless access point was transmitting at a time a user equipment measured signals from the respective wireless access point;   storing, in an almanac data module, the active channels associated with the plurality of wireless access points as a recently used channel information for each of the respective wireless access points;   receiving a coarse position of the mobile device;   determining a subset of almanac data based on the coarse position, wherein the subset of almanac data includes the recently used channel information; and   sending the subset of almanac data to the mobile device.   
     
     
         10 . The method of  claim 9  wherein the recently used channel information includes a frequency. 
     
     
         11 . The method of  claim 9  wherein the subset of almanac data includes a Media Access Control (MAC) address. 
     
     
         12 . The method of  claim 9  wherein receiving the identifiers and the active channels associated with the plurality of wireless access points includes receiving the identifiers and the active channels from the user equipment. 
     
     
         13 . The method of  claim 9  further comprising:
 receiving signal measurements from the mobile device, wherein the signal measurements are based at least in part on the subset of almanac data; 
 determining a position of the mobile device based on the signal measurements; and 
 sending the position to the mobile device. 
 
     
     
         14 . The method of  claim 13  further comprising receiving the identifiers and the active channels from the mobile device. 
     
     
         15 . The method of  claim 14  further comprising storing, in the almanac data module, the active channels received from the mobile device as the recently used channel information. 
     
     
         16 . An apparatus for determining a position of a mobile device, comprising:
 a tangible, non-transitory computer-readable memory;   a processor connected to the tangible, non-transitory computer-readable memory and configured to:
 measure signals from a plurality of wireless access points; 
 determine the position of the mobile device based at least in part on the signals measured; 
 identify a subset of wireless access points from the plurality of wireless access points from which the mobile device was able to measure the signals; 
 identify active channels associated with the subset of wireless access points on which the subset of wireless access points were transmitting at a time that the signals were measured; and 
   a transceiver configured to send identifiers associated with the subset of wireless access points and the active channels to a location server.   
     
     
         17 . The apparatus of  claim 16  where in the transceiver is further configured to:
 send a request to one or more wireless access points to scan for other wireless access points; and 
 receive one or more scan reports from the one or more wireless access points, wherein the processor is configured to measure signals from the one or more wireless access points included in the one or more scan reports. 
 
     
     
         18 . The apparatus of  claim 17  wherein the request includes an indication of one or more channels to be scanned by the one or more wireless access points. 
     
     
         19 . The apparatus of  claim 17  wherein the request includes an indication of a scan type to be performed by the one or more wireless access points. 
     
     
         20 . The apparatus of  claim 16  wherein the processor is configured to determine a set of proximate wireless access points and then measure signals from the set of proximate wireless access points. 
     
     
         21 . The apparatus of  claim 16  wherein the processor is configured to select a set of wireless access points operating on a same channel and then measure signals from the set of wireless access points. 
     
     
         22 . The apparatus of  claim 16  wherein the transceiver is configured to send one or more signal measurements to the location server and receive the position of the mobile device from the location server. 
     
     
         23 . The apparatus of  claim 16  wherein the processor and the transceiver are configured to perform a scan for wireless access points proximate to the mobile device. 
     
     
         24 . An apparatus for providing position assistance data to a mobile device, comprising:
 a tangible, non-transitory computer-readable memory;   a transceiver configured to:
 receive identifiers and active channels associated with a plurality of wireless access points, wherein an active channel indicates a channel on which a respective wireless access point was transmitting at a time a user equipment measured signals from the respective wireless access point; 
 receive a coarse position of the mobile device; 
   a processor connected to the transceiver and the tangible, non-transitory computer-readable memory and configured to:
 store, in an almanac data module, the active channels associated with the plurality of wireless access points as a recently used channel information for each of the respective wireless access points; 
 determine a subset of almanac data based on the coarse position, wherein the subset of almanac data includes the recently used channel information; and 
   the transceiver further configured to send the subset of almanac data to the mobile device.   
     
     
         25 . The apparatus of  claim 24  wherein the recently used channel information includes a frequency. 
     
     
         26 . The apparatus of  claim 24  wherein the subset of almanac data includes a Media Access Control (MAC) address. 
     
     
         27 . The apparatus of  claim 24  wherein the transceiver is configured to receive the identifiers and the active channels from the user equipment. 
     
     
         28 . The apparatus of  claim 24  wherein:
 the transceiver is configured to receive signal measurements from the mobile device, wherein the signal measurements are based at least in part on the subset of almanac data; 
 the processor is configured to determine a position of the mobile device based on the signal measurements; and 
 the transceiver is configured to send the position to the mobile device. 
 
     
     
         29 . The apparatus of  claim 28  wherein the transceiver is configured to receive the identifiers and the active channels from the mobile device. 
     
     
         30 . The apparatus of  claim 29  wherein the processor is configured to store, in the almanac data module, the active channels received from the mobile device as the recently used channel information.