摘要 |
A method for estimating whether or not a wireless terminal is in a zone is described. The method is based on the following observation: when a wireless terminal is at a particular location, the values of the traits of the ambient electromagnetic signals that vary with location represent a "fingerprint" or "signature" for that location. This enables the location of a wireless terminal to be estimated by comparing the observed values of the traits of the ambient electromagnetic signals with the fingerprint for each potential location for the wireless terminal.
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