# US 2014/0152437 A1 · Position location system architecture: messaging and ranging links > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152437 A1 - Document ID: US20140152437A1 - Status: Published application - Kind: A1 - Application number: 13/692,947 - Filed: 2012-12-03 - Published: 2014-06-05 - Earliest claimed: 2012-12-03 - Assignees: QUALCOMM Incoporated - Applicants: Qualcomm Incoporated - Inventors: Bin Tian; Ahmad Jalali - Web page: https://patentgrep.com/patent/US20140152437A1 ## CPC - H04W 4/021: Services related to particular areas, e.g. point of interest [POI] services, venue services or geofences - G01S 5/0289: {of multiple transceivers, e.g. in ad hoc networks} - G01S 5/0295: {Proximity-based methods, e.g. position inferred from reception of particular signals} - G08C 17/02: using a radio link - H04W 4/33: for indoor environments, e.g. buildings - H04W 64/00: Locating users or terminals {or network equipment} for network management purposes, e.g. mobility management - G01S 2205/02: Indoor - H04W 4/023: {using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds} - H04W 4/029: Location-based management or tracking services - H04W 4/80: Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication - H04W 84/18: Self-organising networks, e.g. ad-hoc networks or sensor networks - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - G08C: TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS (fluid pressure transmitting systems F15B; mechanical means for transferring the output of a sensing member into a different variable G01D5/00; mechanical control systems G05G) ## Abstract An indoor position location system. The indoor position location system may include a narrowband messaging link. The narrowband messaging link may enable synchronization and ranging initialization between asset tags and access points of the indoor position location system. The indoor position location system may also include a wideband ranging link. The wideband ranging link may enable a ranging operation between the asset tags, the access points and a position location server of the indoor position location system. The position location server may determine a location of at least one of the asset tags according to the ranging operation. ## Claims ### Claim 1 An indoor position location system, comprising: a narrowband messaging link operable to enable synchronization and ranging initialization between asset tags and access points of the indoor position location system; and a wideband ranging link operable to enable a ranging operation between the asset tags, the access points and a position location server of the indoor position location system, the position location server operable to determine a location of at least one of the asset tags according to the ranging operation. ### Claim 2 (depends on 1) The indoor position location system of claim 1, in which the narrowband messaging link is further operable to periodically broadcast a narrowband pilot signal to the asset tags. ### Claim 3 (depends on 2) The indoor position location system of claim 2, in which the narrowband pilot signal comprises a known preamble and an access point identification field. ### Claim 4 (depends on 2) The indoor position location system of claim 2, in which the narrowband pilot signal comprises a pseudo noise (PN) code to identify one of the access points. ### Claim 5 (depends on 1) The indoor position location system of claim 1, in which the narrowband messaging link is further operable to receive a reduced size packet from the at least one of the asset tags, and in which the narrowband messaging link is further operable to transmit a frequency and/or timing error estimate of the at least one of the asset tags relative to one of the access points after a predetermined delay. ### Claim 6 (depends on 1) The indoor position location system of claim 1, in which the narrowband messaging link is further operable to communicate scheduling information to the asset tags, the scheduling information indicating when the wideband ranging link transmits a wideband ranging preamble and a pseudo noise (PN) sequence of the wideband ranging preamble to initiate the ranging operation. ### Claim 7 A method within an indoor position location system, comprising: periodically waking-up, by an asset tag, to search for a narrowband pilot signal; and synchronizing, by the asset tag, with an access point when the narrowband pilot signal is detected. ### Claim 8 (depends on 7) The method of claim 7, in which the narrowband pilot signal comprises a known preamble as an asset tag identification field. ### Claim 9 (depends on 7) The method of claim 7, in which the narrowband pilot signal comprises a pseudo noise (PN) code to identify the asset tag. ### Claim 10 A method within an indoor position location system, comprising: transmitting, by an asset tag, a reduced size packet to an access point; receiving a frequency and/or timing error estimate of the asset tag relative to the access point; and synchronizing, by the asset tag, with the access point according to the frequency and/or timing error estimate of the asset tag relative to the access point. ### Claim 11 (depends on 10) The method of claim 10, further comprising: initiating a ranging operation with the access point. ### Claim 12 (depends on 11) The method of claim 11, further comprising: waking the asset tag according to received scheduling information regarding a wideband ranging preamble; and performing the ranging operation when a pseudo noise (PN) sequence of the wideband ranging preamble is detected. ### Claim 13 An apparatus of an indoor position location system, comprising: a memory; and at least one processor coupled to the memory and configured: to periodically wake-up to search for a narrowband pilot signal; and to synchronize with an access point when the narrowband pilot signal is detected. ### Claim 14 (depends on 13) The apparatus of claim 13, in which the narrowband pilot signal comprises a known preamble as an access point identification field or a pseudo noise (PN) code to identify the access point. ### Claim 15 A computer program product configured for an indoor position location system, the computer program product comprising: a non-transitory computer-readable medium having non-transitory program code recorded thereon, the non-transitory program code comprising: program code to periodically wake-up to search for a narrowband pilot signal; and program code to synchronize with an access point when the narrowband pilot signal is detected. ### Claim 16 An apparatus of an indoor position location system, comprising: means for periodically waking-up to search for a narrowband pilot signal; and means for synchronizing with an access point when the narrowband pilot signal is detected. ### Claim 17 An apparatus of an indoor position location system, comprising: a memory; and at least one processor coupled to the memory and configured: to transmit a reduced size packet to an access point; to receive a frequency and/or timing error estimate of the apparatus relative to the access point; and to synchronize with the access point according to the frequency and/or timing error estimate of the apparatus relative to the access point. ### Claim 18 (depends on 17) The apparatus of claim 17, in which the at least one processor is further configured: to wake according to received scheduling information regarding a wideband ranging preamble; and to performing a ranging operation when a pseudo noise (PN) sequence of the wideband ranging preamble is detected from the access point. ### Claim 19 A computer program product configured for an indoor position location system, the computer program product comprising: a non-transitory computer-readable medium having non-transitory program code recorded thereon, the non-transitory program code comprising: program code to transmit a reduced size packet to an access point; program code to receive a frequency and/or timing error estimate relative to the access point; and program code to synchronize with the access point according to the frequency and/or timing error estimate relative to the access point. ### Claim 20 An apparatus of an indoor position location system, comprising: means for transmitting a reduced size packet to an access point; means for receiving a frequency and/or timing error estimate of the apparatus relative to the access point; and means for synchronizing with the access point according to the frequency and/or timing error estimate of the apparatus relative to the access point.