Radiolocation using path loss data
First Claim
1. A method comprising:
- accepting an ideal path loss model applicable to an area of interest;
calibrating the ideal path loss model using measurements received from wireless stations of a first set of wireless stations, the measurements measuring the received signal strengths at each respective wireless station of a first set of wireless stations of a wireless network, the stations receiving signals as a result of transmissions by respective wireless stations of a second set of wireless stations of the wireless network, each respective transmission at a known respective transmit power, the locations of each station of the first and second set being known, the calibrating being to determine a calibrated path loss model between the receiving and transmitting wireless stations;
Receiving measurements from a particular wireless station of unknown location, the measurements measuring the received signal strengths at the particular wireless station resulting from respective transmissions from at least some of the stations of the second set of wireless stations, said each of the respective transmissions being at a known corresponding transmit power; and
determining the likely location or locations of the particular wireless station using the received measurements of the received signal strengths at the particular wireless station and the calibrated path loss model.
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Accused Products
Abstract
A method, an apparatus, and a carrier medium to determine the location of a wireless station (a client station of a wireless network or a potential rogue access point). The method includes accepting an ideal path loss model and calibrating the ideal model using path loss measurements between access points at known locations. The calibrating determines a calibrated path loss model between the access points. The method further includes determining path losses between the wireless station of unknown location and at least some of the access points. In the case the wireless station is a client station, the determining includes receiving measurements from the wireless station of unknown location measuring the received signal strengths as a result of respective transmissions from at least some of the access points at known respective transmit powers. In the case the wireless station is an potential rogue access point, the determining includes receiving measurements from at least some of the access points measuring the received signal strength at each of the access points resulting from transmission by the potential rogue access point for each of a set of assumed transmit powers for the potential rogue. The method further includes determining the likely location or locations of the wireless station using the measured path loss and the calibrated path loss model.
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Citations
23 Claims
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1. A method comprising:
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accepting an ideal path loss model applicable to an area of interest; calibrating the ideal path loss model using measurements received from wireless stations of a first set of wireless stations, the measurements measuring the received signal strengths at each respective wireless station of a first set of wireless stations of a wireless network, the stations receiving signals as a result of transmissions by respective wireless stations of a second set of wireless stations of the wireless network, each respective transmission at a known respective transmit power, the locations of each station of the first and second set being known, the calibrating being to determine a calibrated path loss model between the receiving and transmitting wireless stations; Receiving measurements from a particular wireless station of unknown location, the measurements measuring the received signal strengths at the particular wireless station resulting from respective transmissions from at least some of the stations of the second set of wireless stations, said each of the respective transmissions being at a known corresponding transmit power; and determining the likely location or locations of the particular wireless station using the received measurements of the received signal strengths at the particular wireless station and the calibrated path loss model. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method comprising:
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accepting an ideal path loss model applicable to an area of interest; calibrating the ideal path loss model using measurements received from each respective wireless station of a first set of wireless stations of a wireless network measuring the received signal strengths at each of the respective wireless stations, the stations receiving signals as a result of transmissions by respective wireless stations of a second set of wireless stations of the wireless network, each respective transmission at a known respective transmit power, the locations of each station of the first and second set being known or determined, the calibrating being to determine a calibrated path loss model between the receiving and transmitting wireless stations; receiving measurements from each respective station of a third set of wireless stations of the wireless network measuring the received signal strength at each of the respective stations resulting from transmission of a signal from a potential rogue access point, each station of the third set being at a known or determined location; and for each of a set of assumed transmit powers for the potential rogue access point, determining the likely location or locations of the potential rogue access point using the received signal strengths at the stations of the third set and the calibrated path loss model. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A carrier medium carrying one or more code segments to instruct one or more processors of a processing system to execute a method comprising:
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accepting an ideal path loss model applicable to an area of interest; calibrating the ideal path loss model using measurements received from each respective wireless station of a first set of wireless stations of a wireless network measuring the received signal strengths at each of the respective wireless stations of the first set, the stations receiving signals as a result of transmissions by respective wireless stations of a second set of wireless stations of the wireless network, each respective transmission at a known respective transmit power, the locations of each station of the first and second set being known, the calibrating being to determine a calibrated path loss model between the receiving and transmitting wireless stations; receiving measurements from a particular wireless station of unknown location measuring the received signal strengths at the particular wireless station resulting from respective transmissions from at least some of the stations of the second set of wireless stations, said each of the respective transmissions being at a known corresponding transmit power; and determining the likely location or locations of the particular wireless station using the received signal strengths at the particular wireless station and the calibrated path loss model.
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22. An apparatus comprising:
a processing system including a memory and a network interface to couple the apparatus to a network including a set of managed access points of a wireless network, the processing system to; accept an ideal path loss model applicable to an area of interest; instruct each of the managed access points at known locations in the area of interest to measure and report the received signal strengths as a result of transmissions by respective other managed access points of the set, each respective transmission at a known respective transmit power, the locations of each managed access point in the area of interest being known receive the reports of the measurements from the instructed access points; calibrate the ideal path loss model to determine a calibrated path loss model between the receiving and transmitting wireless stations; receive from a particular wireless station of unknown location the received signal strengths resulting from respective transmissions from at least some of the managed access points in the area of interest, said each of the respective transmissions being at a known corresponding transmit power; and determine the likely location or locations of the particular wireless station using the received signal strengths at the particular wireless station and the calibrated path loss model.
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23. A method comprising:
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accepting an ideal path loss model; calibrating the ideal path loss model in an area of interest using path loss determined from measurements between access points of a wireless network, the access points at known locations, the measurements received from some of the access points measuring their received signal strengths resulting from respective transmissions from respective access points, each respective transmission at a known respective transmit power, the calibrating being to determine a calibrated path loss model between the access points; determining the measured path loss between a wireless station of unknown location and at least some of the access points by receiving measurements from the wireless station, wherein in the case the wireless station of unknown location is a client station of one of the access points, the determining uses measurements received from the wireless station of unknown location measuring the received signal strength as a result of respective transmissions from at least some of the access points, said each respective transmissions being at a known respective transmit power, and wherein, in the case the wireless station of unknown location is an potential rogue access point, the determining uses measurements received from each of at least some of the access points measuring the received signal strength at each of the access points resulting from transmission of a signal from the potential rogue access point for each of a set of assumed transmit powers for the potential rogue access point; and determining the likely location or locations of the wireless station of unknown location using the measured path loss and the calibrated path loss model.
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Specification