Patent US6185429B1 successfully refreshed from Google Patents.
US6185429B1
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US
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Method and apparatus for performing a time synchronization of a base site
Assignee: Google Technology Holdings LLC
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Filing: 1998-07-31
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Granted: 2001-02-06
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Expires: 2018-07-31
Abstract
Abstract An unsynchronized base site (104) transmits a time synchronization request to a communication unit (110). A time synchronization error, or a timing offset, for the unsynchronized base site (104) is then determined and transmitted back to the unsynchronized base site (104) to enable the unsynchronized base site to synchronize itself. The time synchronization error is determined for the unsynchronized base site (104) based on the time difference of arrival of the signals received by the communication unit (110) from the base site (104) and at least one synchronized base site (101), the location of the communication unit (110), the location of the base site (104), and the location of the at least one synchronized base site (101).
Inventors
- 👤 James K. Gehrke
- 👤 Timothy J. Groch
- 👤 Steven P. Shipton
- 👤 Mark G. Spiotta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:04
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/24; H04B7/26; H04B7/2662; H04B7/2671; H04B7/2678; H04B7/2687; H04B7/2693
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
260 words
A communication system comprising: a base site that transmits a time synchronization calibration request; a communication unit including: a receiver to receive the time synchronization calibration request; and a transmitter to transmit time difference of arrival information to a controller; at least a second base site to transmit a radio frequency signal to the communication unit and to receive a radio frequency signal from the communication unit; a location-determining device to determine a location of the base site and a location of the at least a second base site; and a controller to determine the location of the communication unit and to calculate time synchronization error for the base site, wherein the controller calculates the time synchronization error according to the following equations: Expected TDOA12−(D1−D2)/(speed of light) Time synchronization error=Expected TDOA12−TDOA12 wherein: D1 is a distance from the location of the communication unit to the location of the at least a second base site; D2 is a distance from the location of the communication unit to the location of the base site; Expected TDOA12 is an expected time difference of arrival for signals received by the communication unit from the base site and the at least a second base site; TDOA12 is a measured time difference of arrival for signals transmitted to the communication unit by the base site and by the at cast a second base site; and Time synchronization error is an amount of time by which a timing reference of the base site is offset from a timing reference of the at least a second base site.
Claim 2
Dependent Claim
260 words
A communication system comprising: a base site that transmits a time synchronization calibration request; a communication unit including: a receiver to receive the time synchronization calibration request; and a transmitter to transmit time difference of arrival information to a controller; at least a second base site to transmit a radio frequency signal to the communication unit and to receive a radio frequency signal from the communication unit; a location-determining device to determine a location of the base site and a location of the at least a second base site; and a controller to determine the location of the communication unit and to calculate time synchronization error for the base site, wherein the controller calculates the time synchronization error according to the following equations: Expected TDOA12−(D1−D2)/(speed of light) Time synchronization error=Expected TDOA12−TDOA12 wherein: D1 is a distance from the location of the communication unit to the location of the at least a second base site; D2 is a distance from the location of the communication unit to the location of the base site; Expected TDOA12 is an expected time difference of arrival for signals received by the communication unit from the base site and the at least a second base site; TDOA12 is a measured time difference of arrival for signals transmitted to the communication unit by the base site and by the at cast a second base site; and Time synchronization error is an amount of time by which a timing reference of the base site is offset from a timing reference of the at least a second base site.
Claim 3
Dependent Claim
25 words
The communication system of claim 1 , wherein the at least a second base site comprises a second base site and a third base site.
Claim 4
Dependent Claim
29 words
The communication system of claim 1 , wherein the at least a second base site comprises a second base site, a third base site, and a fourth base site.
Claim 5
Dependent Claim
34 words
The communication system of claim 1 , wherein the location-determining device that comprises a database that includes the location of the base site and the location of the at least a second base site.
Claim 6
Dependent Claim
17 words
The communication system of claim 1 , wherein the location-determining device is contained within the communication unit.
Claim 7
Dependent Claim
16 words
The communication system of claim 1 , wherein the controller is contained within the communication unit.
Claim 8
Independent Claim
333 words
A method for time synchronization of a base site comprising the steps of: receiving, by a communication unit, a time synchronization request for the base site; receiving, by the communication unit, signals transmitted by the base site and by at least a second base site; determining a location of the base site and a location of the at least a second base site; determining a location of the communication unit; determining a time difference of arrival of a signal transmitted from the base site to the communication unit and a signal transmitted from the at least a second base site to the communication unit; determining a time synchronization error for the base site based on the time difference of arrival of the signals from the base site and the at least a second base site, the location of the communication unit, and the location of the base site, and the location of the at least a second base site; and providing the time synchronization error to the base site, wherein the step of determining the time synchronization error for the base site comprises the step of calculating the time synchronization error according to the following equations: Expected TDOA12=(D1−D2)/(speed of light) Time synchronization error=Expected TDOA12−TDOA12 wherein: D1 is a distance from the location of the communication unit to thc location of the at least a second base site; D2 is a distance from the location of the communication unit to the location of the base site; Expected TDOA12 is an expected time difference of arrival for signals received by the communication unit from the base site and the at least a second base site; TDOA12 is a measured time difference of arrival for signals transmitted to the communication unit by the base site and by the at least a second base site; and Time synchronization error is an amount of time by which a timing reference of the base site is offset from a timing reference of the at least a second base site.
Claim 9
Independent Claim
333 words
A method for time synchronization of a base site comprising the steps of: receiving, by a communication unit, a time synchronization request for the base site; receiving, by the communication unit, signals transmitted by the base site and by at least a second base site; determining a location of the base site and a location of the at least a second base site; determining a location of the communication unit; determining a time difference of arrival of a signal transmitted from the base site to the communication unit and a signal transmitted from the at least a second base site to the communication unit; determining a time synchronization error for the base site based on the time difference of arrival of the signals from the base site and the at least a second base site, the location of the communication unit, and the location of the base site, and the location of the at least a second base site; and providing the time synchronization error to the base site, wherein the step of determining the time synchronization error for the base site comprises the step of calculating the time synchronization error according to the following equations: Expected TDOA12=(D1−D2)/(speed of light) Time synchronization error=Expected TDOA12−TDOA12 wherein: D1 is a distance from the location of the communication unit to thc location of the at least a second base site; D2 is a distance from the location of the communication unit to the location of the base site; Expected TDOA12 is an expected time difference of arrival for signals received by the communication unit from the base site and the at least a second base site; TDOA12 is a measured time difference of arrival for signals transmitted to the communication unit by the base site and by the at least a second base site; and Time synchronization error is an amount of time by which a timing reference of the base site is offset from a timing reference of the at least a second base site.
Claim 10
Dependent Claim
51 words
The method of claim 7 , wherein the step of determining a location of the base site and a location of the at least a second base site comprises the step of determining locations of the base site, a second base site, a third base site, and a fourth base site.
Claim 11
Dependent Claim
69 words
The method of claim 8 , wherein the step of determining the location of the communication unit comprises the step of determining the location of the communication unit based on signals received by the communication unit from the second base site, the third base site, and the fourth base site and locations of the base site, the second base site, the third base site, and the fourth base site.
Claim 12
Dependent Claim
39 words
The method of claim 7 , wherein the step of determining a location of the base site and a location of the at least a second base site comprises the step of querying a database in a locationdetermining device.
Claim 13
Dependent Claim
16 words
The method of claim 10 , wherein the location-determining device is contained in the communication unit.
Claim 14
Dependent Claim
16 words
The method of claim 10 , wherein the location-determining device is contained in a base site.
Claim 15
Independent Claim
191 words
A method for time synchronization of a base site comprising the steps of: transmitting, by the base site, a time synchronization request to a communication unit; receiving, from the communication unit, a time synchronization error; and adjusting a timing reference of the base site based on the time synchronizaton error received from the communication unit, wherein the time synchronization error is defined by the following equations: Expected TDOA12=(D1−D2)/(speed of light) Time synchronization error=Expected TDOA12−TDOA12 wherein: D1 is a distance from a location of the communication unit to a location of a second base site; D2 is a distance from a location of the communication unit to a location of the base site; Expected TDOA12 is an expected time difference of arrival for signals received at the communication unit from the base site and the second base site; TDOA12 is a measured time difference of arrival for signals transmitted to the communication unit by the base site and by the second base site; and Time synchronization error is an amount of time by which the timing reference of the base site is offset from a timing reference of the second base site.
Claim 16
Independent Claim
191 words
A method for time synchronization of a base site comprising the steps of: transmitting, by the base site, a time synchronization request to a communication unit; receiving, from the communication unit, a time synchronization error; and adjusting a timing reference of the base site based on the time synchronizaton error received from the communication unit, wherein the time synchronization error is defined by the following equations: Expected TDOA12=(D1−D2)/(speed of light) Time synchronization error=Expected TDOA12−TDOA12 wherein: D1 is a distance from a location of the communication unit to a location of a second base site; D2 is a distance from a location of the communication unit to a location of the base site; Expected TDOA12 is an expected time difference of arrival for signals received at the communication unit from the base site and the second base site; TDOA12 is a measured time difference of arrival for signals transmitted to the communication unit by the base site and by the second base site; and Time synchronization error is an amount of time by which the timing reference of the base site is offset from a timing reference of the second base site.
References Cited (Backward Citations)
US5128925A
Cited
US5293645A
Cited
US5519759A
Cited
US5722081A
Cited
US5875402A
Cited
US5872774A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-02-06 | 2004-08-07 | 2005-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-02-06 | 2008-08-07 | 2009-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-02-06 | 2012-08-07 | 2013-02-06 | $7700.00 | Window Closed / Lapsed |