Methods and apparatus for identifying asset location in communication networks
First Claim
1. A method for providing a time-of-arrival estimate of a data signal at a receiver, said method comprising:
- receiving said data signal;
demodulating said signal;
decoding said signal to form a decoded signal;
optionally selecting a correlation function for said decoded signal if said data signal is not encoded for time stamping; and
estimating said time-of-arrival using said correlation function.
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Accused Products
Abstract
The location of unmodified wireless assets in a wireless communication network may be identified using time differences of arrivals of a communication sequence at different network receivers. Time-stamping devices may include correlator circuits in parallel with signal decoders to time-stamp communication sequences. Cellular wireless networks may be frequency-multiplexed to increase spatial time-stamping density. Tags may be attached to passive assets to provide location identification information to network devices. Locations of assets broadcasting standard 802.11 radio frequency structures may be identified. Noise inherent in correlating a communication sequence may be reduced by using a selected correlation function.
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Citations
52 Claims
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1. A method for providing a time-of-arrival estimate of a data signal at a receiver, said method comprising:
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receiving said data signal; demodulating said signal; decoding said signal to form a decoded signal; optionally selecting a correlation function for said decoded signal if said data signal is not encoded for time stamping; and estimating said time-of-arrival using said correlation function. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method for identifying a location of an asset in a communication network, said network having at least a first receiver device and a second receiver device, each receiver device having a known position, said method comprising:
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receiving a data signal at each receiver; demodulating said received signal; decoding said signal to form a decoded signal; optionally selecting a correlation function for said decoded signal if said data signal is not encoded for time-stamping; estimating a first time-of-arrival using said correlation function, said first time-of-arrival corresponding to arrival at said first receiver device of a communication sequence transmitted by said asset; estimating a second time-of-arrival using said correlation function, said second time-of-arrival corresponding to arrival at said second receiver device of said communication sequence; and calculating a first time-difference-of-arrivals using said first and second times-of-arrival. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. A method for identifying a location of an asset in a communication network, said network having at least three receivers, said method comprising:
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decoding a data signal from said asset to form a decoded signal; determining if said decoded signal is encoded for time-stamping; selecting a correlation function for estimating a time-of-arrival of a communication sequence at said receivers if said decoded signal is not encoded for time stamping; collecting at least one time-of-arrival estimate for each of said receivers using said correlation function, said estimate corresponding to a time-of-arrival of said communication sequence at a respective one of said receivers; calculating a difference for each of at least two pairs of said estimates; and
estimating said location using said differences. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52)
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Specification