Focused assistance data for wifi access points and femtocells

Abstract

Systems, apparatus and methods for reducing a long list of access points (APs) to a short list of access points are presented. Advantageously, a mobile device only need to search for access points on the short list thereby more quickly discovering access points, saving battery power, determining a position fix based on the discovered access points, and reducing a time to fix. Embodiments enable a mobile device to determine which access points should be detectable at a new location of the mobile device. Various embodiments comprise: (1) a linked database; (2) a grouped database; (3) an associated database; and (4) database feedback.

What is claimed is: 
     
         1 . A method in a location server for determining a position fix of a mobile device in a wireless network, the method comprising:
 receiving, from the mobile device, a rough position;   determining a database based on the rough position; and   sending, to the mobile device, the database;   wherein the database comprises one of a linked database, a grouped database, or an associated database.   
     
     
         2 . The method of  claim 1 , wherein the database comprises the linked database, wherein the linked database links a first access point to a second access point and indicates, that while in a coverage area of a first access point, signals from the second access point are receivable. 
     
     
         3 . The method of  claim 1 , wherein the database comprises the grouped database, wherein the grouped database associates a plurality of access points predicted to have signals receivable from the rough position. 
     
     
         4 . The method of  claim 1 , wherein the database comprises the associated database, wherein the associated database associates a plurality of access points to a macrocell. 
     
     
         5 . The method of  claim 4 , wherein the rough position is indicated by the macrocell. 
     
     
         6 . A location server for determining a position fix of a mobile device in a wireless network, the location server comprising:
 means for receiving, from the mobile device, a rough position;   means for determining a database based on the rough position; and   means for sending, to the mobile device, the database;   wherein the database comprises one of a linked database, a grouped database, or an associated database.   
     
     
         7 . The location server of  claim 6 , wherein the database comprises the linked database, wherein the linked database links a first access point to a second access point and indicates, that while in a coverage area of a first access point, signals from the second access point are receivable. 
     
     
         8 . The location server of  claim 6 , wherein the database comprises the grouped database, wherein the grouped database associates a plurality of access points predicted to have signals receivable from the rough position. 
     
     
         9 . The location server of  claim 6 , wherein the database comprises the associated database, wherein the associated database associates a plurality of access points to a macrocell. 
     
     
         10 . A location server for determining a position fix of a mobile device in a wireless network, the location server comprising:
 a transceiver configured to:
 receive, from the mobile device, a rough position; and 
   
       send, to the mobile device, a database; and
 a processor coupled to the transceiver and configured to determining the database based on the rough position, wherein the database comprises at least one of a linked database, a grouped database, or an associated database. 
 
     
     
         11 . The location server of  claim 10 , wherein the database comprises the linked database, wherein the linked database links a first access point to a second access point and indicates, that while in a coverage area of a first access point, signals from the second access point are receivable. 
     
     
         12 . The location server of  claim 10 , wherein the database comprises the grouped database, wherein the grouped database associates a plurality of access points predicted to have signals receivable from the rough position. 
     
     
         13 . The location server of  claim 10 , wherein the database comprises the associated database, wherein the associated database associates a plurality of access points to a macrocell. 
     
     
         14 . The location server of  claim 13 , wherein the rough position is indicated by the macrocell. 
     
     
         15 . A non-transitory computer-readable storage medium including program code stored thereon for a location server to determine a position fix of a mobile device in a wireless network, the non-transitory computer-readable storage medium comprising program code to:
 receive, from the mobile device, a rough position;   determine a database based on the rough position; and   send to the mobile device, the database;   wherein the database comprises one of a linked database, a grouped database, or an associated database.   
     
     
         16 . The non-transitory computer-readable storage medium of  claim 12 , wherein the database comprises the linked database, wherein the linked database links a first access point to a second access point and indicates, that while in a coverage area of a first access point, signals from the second access point are receivable.