Radio transmitter location finding for wireless communication network services and management
First Claim
1. In a wireless communication system comprising a mobile transmitter and a receiver connected to an antenna array, a method for estimating the location of the mobile transmitter, the method comprising:
- receiving at the antenna array signals originating from the mobile transmitter, wherein the signals comprise p-dimensional array vectors sampled from p antennas of the array;
determining from the received signals a signal signature, wherein the signal signature comprises a measured subspace, wherein the array vectors are approximately confined to the measured subspace;
comparing the signal signature to a database comprising calibrated signal signatures and corresponding location data, wherein the comparing comprises calculating differences between the measured subspace and calibrated subspaces; and
selecting from the database a most likely calibrated signal signature and a corresponding most likely location by using the calculated differences.
6 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for location finding in a wireless communication system uses multipath signals in order to accurately determine a transmitter'"'"'s location. Direct path and multipath signals from a mobile transmitter [74] arrive at an antenna array [80, 82, 84] of a base station receiver [76]. The base station determines signal signature from a subspace of an array covariance matrix. The signature is compared to a database of calibrated signal signatures and corresponding locations, and a location whose calibrated signature best matches the measured signature is selected as the most likely transmitter location. The database of calibrated signal signatures and corresponding locations is generated by a calibration procedure in which a phone [74] transmits location data derived from a GPS receiver [88] and GPS satellites [90, 92, 94] to the base station [76] which records the location information together with the signal signature of the transmitter [74]. The location information can be used to increase the performance of a cellular telephone network and provide useful services to cellular telephone customers.
356 Citations
44 Claims
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1. In a wireless communication system comprising a mobile transmitter and a receiver connected to an antenna array, a method for estimating the location of the mobile transmitter, the method comprising:
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receiving at the antenna array signals originating from the mobile transmitter, wherein the signals comprise p-dimensional array vectors sampled from p antennas of the array; determining from the received signals a signal signature, wherein the signal signature comprises a measured subspace, wherein the array vectors are approximately confined to the measured subspace; comparing the signal signature to a database comprising calibrated signal signatures and corresponding location data, wherein the comparing comprises calculating differences between the measured subspace and calibrated subspaces; and selecting from the database a most likely calibrated signal signature and a corresponding most likely location by using the calculated differences. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. An apparatus for locating a mobile transmitter in a wireless communications system, the apparatus comprising:
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a memory device containing a database of calibrated signal signatures and associated location data, wherein the signal signatures comprise calibrated subspaces; a multichannel receiver connected to an antenna array for receiving signals from the mobile transmitter, wherein the signals comprise p-dimensional array vectors sampled from p antennas of the array; and a signal processor connected to the receiver and to the memory device, wherein the signal processor is programmed to determine from the signals a signal signature comprising a measured subspace to which the array vectors are approximately confined, and to further determine a most likely location from a comparison of the signal signature with the calibrated signal signatures in the memory device, wherein the comparison comprises calculations of differences between the measured subspace and calibrated subspaces. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31)
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32. A wireless communication system comprising:
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a plurality of radio transmitters; a plurality of base stations, wherein each base station comprises an antenna array coupled to signals from the transmitters, a multichannel receiver connected to the antenna array and producing received signals comprising array vectors, a memory storage device containing a database of calibrated signal signatures comprising calibrated subspaces, and a signal processor connected to the receiver and storage device and programmed to calculate signal signatures comprising a measured subspace to which the array vectors are approximately confined and to determine likely locations of the transmitters based upon a comparison of the signal signatures with a database of calibrated signal signatures, wherein the comparison comprises calculations of differences between the measured subspace and calibrated subspaces. - View Dependent Claims (33, 34, 35, 36)
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37. A method for trouble shooting a wireless communication base station comprising an antenna array, a receiver, a memory storage device, and a signal processor, the method comprising:
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receiving signals at the antenna array from a transmitter at a known location; performing a blind estimation of a response of the antenna array, wherein the estimation is based upon the received signals; and comparing the response to a calibrated response stored in the memory device, where the calibrated response is associated with a calibrated location near the known location. - View Dependent Claims (38, 39)
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40. In a wireless communication system comprising a mobile transmitter and a receiver connected to an antenna array, a method for estimating the location of the mobile transmitter, the method comprising:
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receiving at the antenna array signals originating from the mobile transmitter; determining from the received signals a signal signature; comparing the signal signature to a database comprising calibrated signal signatures and corresponding location data; selecting from the database a most likely calibrated signal signature and a corresponding most likely location; and updating the database to correct for changes in the signal propagation environment. - View Dependent Claims (41, 42)
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43. In a wireless location finding system, a method for generating database of locations and corresponding signal signatures, the method comprising:
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receiving at an antenna array signals originating from a moving transmitter, wherein the signals comprise p-dimensional array vectors sampled from p antennas of the array; calculating from the received signals a signal signature, wherein the signal signature comprises a multi-dimensional subspace, and wherein the array vectors are approximately confined to the measured subspace; associating the signal signature with a location of the transmitter; and storing the signal signature and associated location in a calibration database. - View Dependent Claims (44)
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Specification