Methods, systems and devices for providing location based services in a venue

Abstract

Disclosed are methods, systems and devices for providing location based services in a venue. To estimate its location, in a particular implementation, a mobile device may obtain a measurement of a range to a transponder device positioned at a known location based on measurements of a signal round-trip time (RTT) in a message exchange with the transponder device. Positioning assistance data from a server may enable the mobile device to measure a delay at the transponder device in providing a response to a probe message to thereby more accurately measure the signal RTT.

What is claimed is: 
     
         1 . A method at a server, comprising:
 identifying a plurality of access point (AP) devices serving mobile devices in an area;   determining criteria for sorting said plurality of AP devices into groups of AP devices having similar characteristics in imparting a delay in a round-trip signal exchange based, at least in part, on attributes of said plurality of AP devices, wherein said group of AP devices have an attribute in common comprising an AP model attribute, an AP vendor attribute or an AP LAN chip vendor attribute or a combination thereof, and wherein said delay comprises a turnaround calibration factor (TCF) delay or a cyclic shift diversity (CSD) delay;   sorting said plurality of AP devices into said groups of AP devices according to said criteria; and   transmitting, in response to a request for positioning assistance data, one or more messages to at least one mobile device comprising identities of said plurality of AP devices and an indication of said plurality of AP devices in said groups of AP devices.   
     
     
         2 . A server, comprising:
 a wireless transceiver to transmit messages to and receive messages from a wireless communication network; and   one or more processors to:   identify a plurality of access point (AP) devices serving mobile devices in an area;   determine criteria for sorting said plurality of AP devices into groups of AP devices having similar characteristics in imparting a delay in a round-trip signal exchange based, at least in part, on attributes of said plurality of AP devices, wherein said group of AP devices have an attribute in common to comprise an AP model attribute, an AP vendor attribute or an AP LAN chip vendor attribute or a combination therefore, and wherein said delay to comprise a turnaround calibration factor (TCF) delay or a cyclic shift diversity (CSD) delay or combination thereof;   sort said plurality of AP devices into said groups of AP devices according to said criteria; and   initiate transmission of one or more response messages through said wireless transceiver, in response to receipt of one or more messages at said wireless transceiver for positioning assistance data, to at least one mobile device, said one or more response messages comprising identities of said plurality of AP devices and an indication of said plurality of AP devices in said groups of AP devices.   
     
     
         3 . An apparatus for use in a server, said apparatus comprising:
 means for identifying a plurality of access point (AP) devices serving mobile devices in an area;   means for determining criteria for sorting said plurality of AP devices into groups of AP devices having similar characteristics in imparting a delay in a round-trip signal exchange based, at least in part, on attributes of said plurality of AP devices, wherein said group of AP devices have an attribute in common comprising an AP model attribute, an AP vendor attribute or an AP LAN chip vendor attribute or a combination thereof, and wherein said delay comprises a turnaround calibration factor (TCF) delay or a cyclic shift diversity (CSD) delay;   means for sorting said plurality of AP devices into said groups of AP devices according to said criteria;   means for transmitting, in response to a request for positioning assistance data, one or more messages to at least one mobile device comprising identities of said plurality of AP devices and an indication of said plurality of AP devices in said groups of AP devices.   
     
     
         4 . An article for use in a server, said article comprising a non-transitory computer readable medium having stored therein computer implementable instructions executable by a processing unit in said server to:
 identify a plurality of access point (AP) devices serving mobile devices in an area;   determine criteria for sorting said plurality of AP devices into groups of AP devices to have similar characteristics to impart a delay in a round-trip signal exchange based, at least in part, on attributes of said plurality of AP devices, wherein said groups of AP devices have an attribute in common to comprise an AP model attribute, an AP vendor attribute or an AP LAN chip vendor attribute or a combination thereof, and wherein said delay to comprise a turnaround calibration factor (TCF) delay or a cyclic shift diversity (CSD) delay;   sort said plurality of AP devices into said groups of AP devices according to said criteria;   
       transmit, in response to a request for positioning assistance data, one or more messages to at least one mobile device comprising identities of said plurality of AP devices and an indication of said plurality of AP devices in said groups of AP devices.