Location estimation of wireless terminals through pattern matching of deduced and empirical signal-strength measurements
First Claim
1. A method comprising:
- receiving a signal-strength measurement for a first downlink signal that is received by a wireless terminal and a signal-strength measurement for an uplink signal that is transmitted by said wireless terminal; and
estimating the location of said wireless terminal based on said signal-strength measurement for said first downlink signal and on said signal-strength measurement for said uplink signalwherein estimating the location of said wireless terminal comprises pattern matching (i) said signal-strength measurement for said downlink signal against a map that correlates signal-strength measurements and locations.
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Accused Products
Abstract
A method of estimating the location of a wireless terminal is disclosed. The illustrative embodiment of the present invention is based on the observation that the signal strength of a signal from a transmitter is different at some locations, and, therefore, the location of a wireless terminal can be estimated by comparing the signal strength it currently observes against a map or database that correlates locations to signal strengths. Furthermore, the illustrative embodiment deduces the signal strength of one or more base stations'"'"' control channels at the wireless terminal based on the principal of reciprocity, whether or not the wireless terminal can actually receive the base stations'"'"' control channels but so long as the base station can receive and measure the uplink signal from the wireless terminal. The deduced signal-strength measurements can then used—alone or in combination with the empirical signal-strength measurements—to estimate the location of the wireless terminal.
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Citations
19 Claims
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1. A method comprising:
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receiving a signal-strength measurement for a first downlink signal that is received by a wireless terminal and a signal-strength measurement for an uplink signal that is transmitted by said wireless terminal; and estimating the location of said wireless terminal based on said signal-strength measurement for said first downlink signal and on said signal-strength measurement for said uplink signal wherein estimating the location of said wireless terminal comprises pattern matching (i) said signal-strength measurement for said downlink signal against a map that correlates signal-strength measurements and locations. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method comprising:
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receiving (i) a first signal-strength measurement for an uplink signal that is transmitted by a wireless terminal and received at a first location and (ii) a second signal-strength measurement for said uplink signal that is transmitted by said wireless terminal and received at a second location; deducing the signal strength of a first downlink signal at said wireless terminal based on said first signal-strength measurement for said uplink signal; deducing the signal strength of a second downlink signal at said wireless terminal based on said second signal-strength measurement for said uplink signal; and estimating the location of said wireless terminal based on the deduced signal strength of said first downlink signal and on the deduced signal strength of said second downlink signal. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method comprising:
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transmitting a request to a mobile switching center to make a first signal-strength measurement at a first location and a second signal-strength measurement at a second location for an uplink signal that is transmitted by a wireless terminal; receiving a message from said mobile switching center that comprises said first signal-strength measurement and said second signal-strength measurement; deducing the signal strength of a first downlink signal at said wireless terminal based on said first signal-strength measurement; deducing the signal strength of a second downlink signal at said wireless terminal based on said second signal-strength measurement; and estimating the location of said wireless terminal based on the deduced signal strength of said first downlink signal and on the deduced signal strength of said second downlink signal. - View Dependent Claims (16, 17, 18, 19)
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Specification