Location estimation in narrow bandwidth wireless communication systems
First Claim
1. A method of determining the location of a wireless mobile communication device operating in a wireless communication system, comprising:
- the wireless mobile communication device transmitting a first waveform over a wireless communication link;
receiving the first waveform at each of a plurality of known locations;
receiving at each of the plurality of known locations a reference waveform produced by a stationary source;
for each of the known locations, producing information indicative of a phase difference between the first waveform as received at the known location and the reference waveform as received at the known location; and
using said information to determine the location of the wireless mobile communication device.
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Accused Products
Abstract
The phase difference between a known stable reference signal (11) and a known signal output by a wireless mobile communication device (5, 5B) is determined at several known locations (1-4, 1B-4B). The location of the wireless mobile communication device is then determined from the phase difference information. Also, the approximate location of a wireless mobile communication device (5A) can be estimated by transmitting a message from the device at a predetermined power level (71), and determining where among a plurality of predetermined locations (1A-4A) the transmitted message has been received.
75 Citations
20 Claims
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1. A method of determining the location of a wireless mobile communication device operating in a wireless communication system, comprising:
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the wireless mobile communication device transmitting a first waveform over a wireless communication link;
receiving the first waveform at each of a plurality of known locations;
receiving at each of the plurality of known locations a reference waveform produced by a stationary source;
for each of the known locations, producing information indicative of a phase difference between the first waveform as received at the known location and the reference waveform as received at the known location; and
using said information to determine the location of the wireless mobile communication device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A wireless communication system, comprising:
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a wireless mobile communication device for transmitting a first waveform over a wireless communication link;
a stationary reference source for producing a reference waveform;
a plurality of stationary location markers respectively provided at a plurality of predetermined locations for receiving the first waveform, each said location marker coupled to said reference source for receiving the reference waveform;
each said location marker responsive to the first waveform and the reference waveform for producing information indicative of a phase difference between the first waveform and the reference waveform as received at said location marker; and
a location determiner coupled to said location markers for receiving said information from said location markers and determining from said information the location of said wireless mobile communication device. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. An apparatus for use in determining the location of a wireless mobile communication device operating in a wireless mobile communication system, comprising:
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an input fixed at a known location for receiving a first waveform from the wireless mobile communication device via a wireless communication link;
a second input fixed at said known location for receiving a reference waveform from a stationary source;
a phase comparator coupled to said inputs for determining a phase difference between said first waveform and said reference waveform as received at said inputs; and
an output coupled to said phase comparator for outputting information indicative of said phase difference to a location determiner which can use said information to determine the location of the wireless mobile communication device. - View Dependent Claims (17, 18, 19, 20)
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Specification