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US 6,230,018 B1Granted
Devices and processing in a mobile radio communication network having calibration terminals
AssigneeNortel Networks Limited
InventorsJ. Michael Watters, Leo Strawczynski, David Steer
Life of this patent
Estimating the term…
Abstract
In a mobile communication network, the accuracy of location determinations for mobiles based on TDOA measurements made by the mobiles is increased by measuring the TDOA of signals from base station pairs at a known location and generating correction factors for compensating timing and propagation errors in TDOA measurements made by the mobiles. Calibration terminals may be provided for measuring TDOAs at known locations. System processes and elements for applying data generated by calibration terminals are disclosed.
Claims62
A process in a mobile communication network, comprising:
- determining an expected time difference of arrival (TDOA) at a known location for signals of at least three base station pairs of the network;
- determining a measured TDOA for each of said base station pairs at said known location;
- determining an average measured TDOA for each of the base station pairs at said known location for a period of time;
- determining a correction factor for each base station pair constituting the difference between the expected and average measured TDOAs;
- determining a measured TDOA at a location of a mobile for each of said base station pairs;
- for each of said base station pairs, if a TDOA at the location of the mobile differs from a corresponding TDOA at the known location by less than a predetermined amount, applying a corresponding correction factor to said measured TDOA to yield a corrected TDOA;
- and
- determining a location using said corrected TDOAs.
5 more elements
A mobile communication network, comprising:
- means for determining an expected time difference of arrival (TDOA) at a known location for signals of at least three base station pairs of the network;
- means for determining a measured TDOA for each of said base station pairs at said known location;
- means for determining an average measured TDOA for each of the base station pairs at said known location for a period of time;
- means for determining a correction factor for each base station pair constituting the difference between the expected and average measured TDOAs;
- means for determining a measured TDOA at a location of a mobile for each of said base station pairs;
- means for individually applying a corresponding correction factor to each measured TDOA to yield a corrected TDOA if a corresponding TDOA at the location of the mobile differs from a corresponding TDOA at the known location by less than a predetermined amount;
- and
- means for determining a location using said corrected TDOAs.
5 more elements
A process in a mobile communication network for synchronizing a base station and a reference base station, comprising:
- determining a measured time difference of arrival (TDOA) at a known location of a signal from a base station with respect to a signal from a reference base station;
- determining an expected TDOA for the base station with respect to the reference base station;
- determining a difference between the measured and expected TDOAs;
- and
- adjusting the timing of the base station by the amount of the difference to align a PN offset of the base station with a PN offset of the reference base station.
2 more elements
A mobile communication network for providing synchronization of a base station and a reference base station, comprising:
- means for determining a measured time difference of arrival (TDOA) at a known location of a signal from a base station with respect to a signal from a reference base station;
- means for determining an expected TDOA for the base station with respect to the reference base station;
- means for determining a difference between the measured and expected TDOAs;
- and
- means for adjusting the timing of the base station by the amount of the difference to align a PN offset of the base station with a PN offset of the reference base station.
2 more elements
A process in a mobile communication network for synchronizing a base station and a reference base station, comprising:
- determining an average measured time difference of arrival (TDOA) at a known location of a signal from a base station with respect to a signal from a reference base station;
- determining an expected TDOA for the base station with respect to the reference base station;
- determining a difference between the measured and expected TDOAs;
- and
- adjusting the timing of the base station by the amount of the difference to align a PN offset of the base station with a PN offset of the reference base station.
2 more elements
A mobile communication network for providing synchronization of a base station and a reference base station, comprising:
- means for determining an average measured time difference of arrival (TDOA) at a known location of a signal from a base station with respect to a signal from a reference base station;
- means for determining an expected TDOA for the base station with respect to the reference base station;
- means for determining a difference between the measured and expected TDOAs;
- and
- means for adjusting the timing of the base station by the amount of the difference to align a PN offset of the base station with a PN offset of the reference base station.
2 more elements
A process in a mobile of a mobile communication network, comprising:
- measuring a time difference of arrival (TDOA) at the mobile for at least three base station pairs of the network;
- receiving, from another element of the network, a correction factor associated with each of said base station pairs;
- applying said correction factors to corresponding TDOA measurements to yield corrected TDOA measurements;
- and
- determining a location from said corrected TDOA measurements.
2 more elements
A mobile of a mobile communication network, comprising:
- means for measuring a time difference of arrival (TDOA) at the mobile for at least three base station pairs of the network;
- means for receiving, from another element of the network, a correction factor associated with each of said base station pairs;
- means for applying said correction factors to corresponding TDOA measurements to yield corrected TDOA measurements;
- and
- means for determining a location from said TDOA measurements.
2 more elements
A process in an element of a mobile communication network, comprising:
- determining time difference of arrival (TDOA) measurements at the location of a mobile of the network for at least three base station pairs of the network;
- receiving, from another element of the network, correction factors corresponding to each of said at least two base station pairs;
- applying correction factors to corresponding TDOA measurements to yield corrected TDOA measurements;
- and
- determining a location of the mobile from said corrected TDOA measurements.
2 more elements
An element of a mobile communication network, comprising:
- means for determining time difference of arrival (TDOA) measurements at the location of a mobile of the network for at least three base station pairs of the network;
- means for receiving, from another element of the network, correction factors corresponding to each of said at least two base station pairs;
- means for applying correction factors to corresponding TDOA measurements to yield corrected TDOA measurements;
- means for determining a location of the mobile from said corrected TDOA measurements;
- and
- means for providing the determined location to a service provider specified by the mobile.
3 more elements
A calibration terminal of a mobile communication network, comprising:
- means for determining a time difference of arrival (TDOA) measurement for signals of a base station pair of the network;
- means for determining an expected TDOA of said signals at the location of the calibration terminal;
- means for determining a correction factor for the base station pair constituting a difference between the TDOA measurement and the expected TDOA measurement;
- and
- means for periodically reporting said correction factor and identification of said base station pair.
2 more elements
A calibration terminal of a mobile communication network, comprising:
- means for determining a time difference of arrival (TDOA) measurement for signals of a base station pair of the network;
- means for determining an expected TDOA of said signals at the location of the calibration terminal;
- means for determining a correction factor for the base station pair constituting a difference between the TDOA measurement and the expected TDOA measurement;
- means for receiving a query comprising an identification of said base station pair;
- and
- means for providing said correction factor in response to said query.
3 more elements
A calibration terminal of a mobile communication network, comprising:
- means for determining an average measured time difference of arrival (TDOA) for signals of a base station Pair of the network;
- means for determining an expected TDOA of said signals at the location of the calibration terminal;
- means for determining a fixed error correction factor constituting a difference between the average of TDOA measurements and the expected TDOA measurement;
- and
- means for periodically reporting said correction factor and identification of said base station pair.
2 more elements
A calibration terminal of a mobile communication network, comprising:
- means for determining an average measured time difference of arrival (TDOA) for signals of a base station pair of the network;
- means for determining an expected TDOA of said signals at the location of the calibration terminal;
- means for determining a fixed error correction factor constituting a difference between the average of TDOA measurements and the expected TDOA measurement;
- means for receiving a query comprising an identification of said base station pair;
- and
- means for providing said fixed error and variable error correction factors in response to said query.
3 more elements
A process in a base station of a communication network, comprising:
- providing a query to a calibration terminal of said network comprising identification of said base station and a reference base station;
- receiving a difference of a time difference of arrival (TDOA) at a known location of a signal from said base station relative to a signal from the reference base station and an expected TDOA at said known location of a signal from said base station relative to a signal from said reference base station;
- and
- adjusting timing of said signal of said base station by an amount of said difference to align a PN offset of the base station with a PN offset of the reference base station.
1 more element
A base station of a communication network, comprising:
- means for providing a query to a calibration terminal of said network comprising identification of said base station and a reference base station;
- means for receiving a difference of a time difference of arrival (TDOA) at a known location of a signal from said base station relative to a signal from the reference base station and an expected TDOA at said known location of a signal from said base station relative to a signal from said reference base station;
- and
- means for adjusting timing of said signal of said base station by an amount of said difference to align a PN offset of the base station with a PN offset of the reference base station.
1 more element
A process in a base station of a communication network, comprising:
- determining a difference of an average measured time difference of arrival (TDOA) at a known location of a signal from said base station relative to a signal from a reference base station and an expected TDOA at said known location of a signal from said base station relative to a signal from said reference base station;
- and
- adjusting timing of said signal of said base station by an amount of said difference to align a PN offset of the base station with a PN offset of the reference base station.
A base station of a communication network, comprising:
- means for determining a difference of an average measured time difference of arrival (TDOA) at a known location of a signal from said base station relative to a signal from a reference base station and an expected TDOA at said known location of a signal from said base station relative to a signal from said reference base station;
- and
- means for adjusting timing of said signal of said base station by an amount of said difference to align a PN offset of the base station with a PN offset of the reference base station.
A process in a base station of a communication network, comprising:
- providing a query to a calibration terminal of said network comprising identification of said base station and a reference base station;
- receiving from the calibration terminal a correction factor for time difference of arrival (TDOA) measurements for said base station and said reference base station;
- storing said correction factor;
- and
- periodically broadcasting said correction factor in conjunction with identification of said base station and said reference base station.
2 more elements
A base station of a communication network, comprising:
- means for providing a query to a calibration terminal of said network comprising identification of said base station and a reference base station;
- means for receiving from said calibration terminal a correction factor for time difference of arrival (TDOA) measurements for said base station and said reference base station;
- means for storing said correction factor;
- and
- means for periodically broadcasting said correction factor in conjunction with identification of said base station and said reference base station.
2 more elements
Dependencies are inferred from the claim text.