US5945948A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for location finding in a communication system
Assignee: Google Technology Holdings LLC
•
Filing: 1996-09-03
•
Granted: 1999-08-31
•
Expires: 2016-09-03
Abstract
Abstract A method for determining a subscriber unit location in a communication system is provided. The method includes the steps of receiving a signal from the subscriber unit at a first base station, determining a first receive time of the signal based on a sequence of spreading symbols at the first base station, determining a first angle of arrival of the signal at the first base station, and determining the location of the subscriber unit from the first receive time, the first angle of arrival, and further predetermined information about the first base station. The signal is formed via modulation by the sequence of spreading symbols.
Inventors
- 👤 Kevin A. Buford
- 👤 John D. Reed
- 👤 Walter J. Rozanski, Jr.
- 👤 Amitava Ghosh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:49
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/02; H; H04; H04W; H04W64/00; G01S5/00; G01S5/02; G01S5/0205; G01S5/021; G01S5/04; G01S5/12; G01S5/0215; G01S5/0294
Claims Analysis
Total Claims: 55
Claim 1
Independent Claim
115 words
A method for estimating a subscriber unit location in a communication system, the method comprising the steps of: receiving a signal from the subscriber unit at a first base station the signal being formed via modulation by a sequence of spreading symbols; determining a first receive time of the signal based on the sequence of spreading symbols at the first base station, determining an estimate of a first angle of arrival of the signal at the first base station, the estimate being determined using a fixed beam antenna; and determining the location of the subscriber unit from the first receive time, the first angle of arrival, and further predetermined information about the first base station.
Claim 2
Independent Claim
115 words
A method for estimating a subscriber unit location in a communication system, the method comprising the steps of: receiving a signal from the subscriber unit at a first base station the signal being formed via modulation by a sequence of spreading symbols; determining a first receive time of the signal based on the sequence of spreading symbols at the first base station, determining an estimate of a first angle of arrival of the signal at the first base station, the estimate being determined using a fixed beam antenna; and determining the location of the subscriber unit from the first receive time, the first angle of arrival, and further predetermined information about the first base station.
Claim 3
Dependent Claim
28 words
The method of claim 1, further comprising the step of determining a second receive time of the signal based on the spreading sequence at a second base station.
Claim 4
Dependent Claim
36 words
The method of claim 2, further comprising the step of determining an estimate of a second angle of arrival of the signal at the second base station the estimate being determined using a fixed beam antenna.
Claim 5
Dependent Claim
29 words
The method of claim 3, further comprising the step of determining the location of the subscriber unit based on the second receive time and the second angle of arrival.
Claim 6
Dependent Claim
28 words
The method of claim 2, further comprising the step of determining a third receive time of the signal based on the spreading sequence at a third base station.
Claim 7
Dependent Claim
30 words
The method of claim 5, further comprising determining an estimate of a third angle of arrival at the third base station, the estimate being determined using a fixed beam antenna.
Claim 8
Dependent Claim
15 words
The method of claim 2, wherein the second base station comprises an auxiliary base station.
Claim 9
Dependent Claim
15 words
The method of claim 2, wherein the second base station comprises a microcell base station.
Claim 10
Dependent Claim
18 words
The method of claim 1, wherein the fixed beam of the antenna is formed using an antenna array.
Claim 11
Dependent Claim
14 words
The method of claim 1, wherein the fixed beam antenna is a sector antenna.
Claim 12
Dependent Claim
15 words
The method of claim 1, further comprising adjusting system gain for a given subscriber unit.
Claim 13
Dependent Claim
17 words
The method of claim 1, wherein the received signal has a first ray and a second ray.
Claim 14
Dependent Claim
32 words
The method of claim 12, further comprising the step of adjusting a time offset in a receiver of the first base station in response to the first ray of the received signal.
Claim 15
Dependent Claim
24 words
The method of claim 12, further comprising the step of adjusting an antenna array in response to the first ray of the received signal.
Claim 16
Dependent Claim
33 words
The method of claim 12, further comprising the step of detecting the first ray with a first finger of the receiver and detecting the second ray with a second finger of the receiver.
Claim 17
Dependent Claim
17 words
The method of claim 1, further comprising the step of increasing the transmit power of the signal.
Claim 18
Dependent Claim
26 words
The method of claim 16, wherein the transmit power is increased in response to a control signal from the first base site to the subscriber unit.
Claim 19
Dependent Claim
23 words
The method of claim 16, wherein the transmit power is increased by adding delay prior to responding to a subscriber unit access request.
Claim 20
Dependent Claim
22 words
The method of claim 16, wherein the transmit power is increased by decreased antenna gain in the direction of the subscriber unit.
Claim 21
Dependent Claim
30 words
The method of claim 1, further comprising the step of adjusting the estimate of the first angle of arrival to determine an adjusted estimate of the first angle of arrival.
Claim 22
Dependent Claim
24 words
The method of claim 20, wherein the adjusted estimate of the first angle of arrival is determined based on information from a geographic database.
Claim 23
Dependent Claim
14 words
The method of claim 21, wherein the geographic database comprises location zone mapping data.
Claim 24
Dependent Claim
12 words
The method of claim 1, wherein the predetermined information comprises a database.
Claim 25
Dependent Claim
12 words
The method of claim 23, wherein the database comprises a road database.
Claim 26
Dependent Claim
23 words
The method of claim 1, further comprising the step of calibrating the determined location by comparing the determined location with a calibration measurement.
Claim 27
Dependent Claim
15 words
The method of claim 25, wherein the calibration measurement is determined using a GPS receiver.
Claim 28
Dependent Claim
17 words
The method of claim 25, wherein the calibration measurement is a known location of a fixed unit.
Claim 29
Dependent Claim
23 words
The method of claim 1, further comprising the step of determining a height estimate of the subscriber unit based on the received signal.
Claim 30
Dependent Claim
16 words
The method of claim 28, wherein the height estimate is determined using a patch array antenna.
Claim 31
Dependent Claim
15 words
The method of claim 29, wherein the height estimate is determined using a vertical antenna.
Claim 32
Dependent Claim
21 words
The method of claim 29, wherein the height estimate is determined using an antenna below a roof top of a building.
Claim 33
Dependent Claim
21 words
The method of claim 1, further comprising the step of tracking the subscriber unit by performing a plurality of location measurements.
Claim 34
Dependent Claim
19 words
The method of claim 32, further comprising the step of comparing a location measurement with a prior location measurement.
Claim 35
Dependent Claim
22 words
The method of claim 2, further comprising handing off a call at one of the base stations to a second communication system.
Claim 36
Dependent Claim
17 words
The method of claim 1, further comprising performing a second location measurement using a second communication system.
Claim 37
Dependent Claim
23 words
The method of claim 35, wherein the communication system comprises a CDMA system and the second communication system comprises an analog cellular system.
Claim 38
Dependent Claim
22 words
The method of claim 1, further comprising the step of determining whether the subscriber unit crosses a boundary into a predefined area.
Claim 39
Dependent Claim
19 words
The method of claim 37, including the step of reporting the subscriber unit's boundary crossing to a predefined entity.
Claim 40
Independent Claim
126 words
A method for estimating a subscriber unit location in a communication system, the method comprising the steps of: performing a first location measurement having a first confidence level by: receiving a signal from the subscriber unit at a first base station, the signal being formed via modulation by a sequence of spreading symbols; determining a first receive time of the signal based on the sequence of spreading symbols at the first base station, and determining an estimate of a first angle of arrival of the signal at the first base station, the estimate being determined using a fixed beam antenna; performing a second location measurement having a second confidence level; determining an estimated location of the subscriber unit based on the first and second location measurements.
Claim 41
Independent Claim
126 words
A method for estimating a subscriber unit location in a communication system, the method comprising the steps of: performing a first location measurement having a first confidence level by: receiving a signal from the subscriber unit at a first base station, the signal being formed via modulation by a sequence of spreading symbols; determining a first receive time of the signal based on the sequence of spreading symbols at the first base station, and determining an estimate of a first angle of arrival of the signal at the first base station, the estimate being determined using a fixed beam antenna; performing a second location measurement having a second confidence level; determining an estimated location of the subscriber unit based on the first and second location measurements.
Claim 42
Dependent Claim
21 words
The method of claim 35, wherein the second location measurement is based on a measurement from at least two base stations.
Claim 43
Dependent Claim
35 words
The method of claim 34, wherein the second location measurement is based on a measurement from three base stations and wherein the second location measurement has a higher confidence level than the first location measurement.
Claim 44
Dependent Claim
27 words
The method of claim 35, further comprising determining the estimated location of the subscriber unit based on a weighted combination of the first and second location measurements.
Claim 45
Dependent Claim
27 words
The method of claim 39, wherein the first location measurement is taken at a first time and the second location measurement is taken at a second time.
Claim 46
Dependent Claim
19 words
The method of claim 39, wherein the second location measurement is a calibrated measurement having a high confidence level.
Claim 47
Dependent Claim
173 words
A communication system having plural base stations and operable for locating a communication unit, the communication system comprising: a controller responsive to a first and a second base station, each of the first and second base stations comprising a receiver operable for receiving a signal from the communication unit, the signal being formed via modulation by a sequence of spreading symbols, the receiver adapted to be coupled to an antenna having a limited angle of reception, the receiver configured to determine an estimate of a first angle of arrival of the signal and a detector operable for determining a receive time of the signal based on the sequence; and a location processor responsive to the controller operable for requesting the first and second base stations to determine first and second receive times of the signal based on the sequence, and for determining a location of the communication unit from the first and second receive times, the first angle of arrival of the signal, and further information about the first and second base stations.
Claim 48
Dependent Claim
173 words
A communication system having plural base stations and operable for locating a communication unit, the communication system comprising: a controller responsive to a first and a second base station, each of the first and second base stations comprising a receiver operable for receiving a signal from the communication unit, the signal being formed via modulation by a sequence of spreading symbols, the receiver adapted to be coupled to an antenna having a limited angle of reception, the receiver configured to determine an estimate of a first angle of arrival of the signal and a detector operable for determining a receive time of the signal based on the sequence; and a location processor responsive to the controller operable for requesting the first and second base stations to determine first and second receive times of the signal based on the sequence, and for determining a location of the communication unit from the first and second receive times, the first angle of arrival of the signal, and further information about the first and second base stations.
Claim 49
Dependent Claim
130 words
A wireless communication system, comprising: a first base station in wireless communication with a subscriber unit, the first base station receiving a signal from the subscriber unit, the signal being formed via modulation by a sequence of spreading symbols; a first time of arrival detector determining a first receive time of the signal based on the sequence of spreading symbols at the first base station, an angle of arrival detector adapted to be coupled to a fixed beam antenna, said angle of arrival detector determining a first angle of arrival of the signal at the first base station; and a location estimation unit determining an estimated location of the subscriber unit from the first receive time, the first angle of arrival, and further predetermined information about the first base station.
Claim 50
Dependent Claim
130 words
A wireless communication system, comprising: a first base station in wireless communication with a subscriber unit, the first base station receiving a signal from the subscriber unit, the signal being formed via modulation by a sequence of spreading symbols; a first time of arrival detector determining a first receive time of the signal based on the sequence of spreading symbols at the first base station, an angle of arrival detector adapted to be coupled to a fixed beam antenna, said angle of arrival detector determining a first angle of arrival of the signal at the first base station; and a location estimation unit determining an estimated location of the subscriber unit from the first receive time, the first angle of arrival, and further predetermined information about the first base station.
Claim 51
Dependent Claim
20 words
The wireless communication system of claim 46, further comprising a second base station in wireless communication with the subscriber unit.
Claim 52
Dependent Claim
35 words
The wireless communication system of claim 47, further comprising a second time of arrival detector determining a second receive time of the signal based on the sequence of spreading symbols at the second base station.
Claim 53
Dependent Claim
20 words
The system of claim 48, further comprising a second angle of arrival detector in communication with the second base station.
Claim 54
Dependent Claim
14 words
The system of claim 46, wherein the fixed beam antenna comprises a sectorized antenna.
Claim 55
Dependent Claim
14 words
The system of claim 46, wherein the fixed beam antenna comprises an antenna array.
References Cited (Backward Citations)
US5265121A
Cited
US5506864A
Cited
US5515378A
Cited
US5175558A
Cited
US5583517A
Cited
US5317323A
Cited
US5508708A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-08-30 | 2003-03-01 | 2003-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-08-30 | 2007-03-01 | 2007-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-08-30 | 2011-03-01 | 2011-08-31 | $7700.00 | Window Closed / Lapsed |