Method and system for improving time of arrival (TOA) measurements in a wirless communication network
First Claim
1. A method of estimating time of arrival (TOA) in an ad-hoc communications network, comprising the steps of:
- sending a ranging message from a first node to a second node;
receiving a signal at the second node;
measuring the TOA of the received signal;
correlating the received signal with a reference signal to obtain a measured correlation function;
estimating a phase delay of the received signal utilizing the measured correlation function;
constructing a reference correlation function based on the amplitude and the phase delay of the measured correlation function; and
calculating a score based on similarities between the reference correlation function and the measured correlation function.
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Abstract
A technique for improving the capability of measuring the distance between nodes of a wireless communication network is provided. Technique (800) includes receiving a measured signal, correlating the measured signal with a reference signal to output a measured correlated function, comparing the correlation function to a predetermined reference correlation function, the reference correlation function being based on a predetermined direct path sequence and an estimation of the phase delay of the measured correlated function. A score is assigned to the measured correlation function based on how close the measured correlation function resembles the predetermined reference correlation function. Technique (800) provides improved location accuracy, even in multipath environments, by indicating the quality of the TOA measurement and enabling the selection of a correction mechanism.
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Citations
10 Claims
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1. A method of estimating time of arrival (TOA) in an ad-hoc communications network, comprising the steps of:
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sending a ranging message from a first node to a second node;
receiving a signal at the second node;
measuring the TOA of the received signal;
correlating the received signal with a reference signal to obtain a measured correlation function;
estimating a phase delay of the received signal utilizing the measured correlation function;
constructing a reference correlation function based on the amplitude and the phase delay of the measured correlation function; and
calculating a score based on similarities between the reference correlation function and the measured correlation function. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for improving the capability of measuring the distance between nodes of a wireless communication network, comprising the steps of:
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receiving a signal at a node;
measuring TOA of the received signal;
correlating the received signal with a reference signal to output a measured correlation function;
comparing the measured correlation function to a reference correlation function, the reference correlation function being based on a predetermined direct path sequence and an estimation of the phase delay of the measured correlated function;
assigning a score to the measured correlation function based on how close the measured correlation function resembles the reference correlation function;
indicating the quality of the TOA measurement based on the assigned score; and
enabling the selection of a correction mechanism for the measured received signal based on the quality.
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- 9. An ad-hoc communication network, comprising a plurality of nodes, at least one operating as a ranger node and another operating as a pinger node, the ranger node using time of arrival (TOA) measurements to generate a measured correlation function, wherein based on estimated phase delay of the measured correlation function, a reference correlation function is constructed and compared to the measured correlation function, and a score is assigned to the measured correlation function in order to provide an indication of direct path and multipath so that a direct path can be used make accurate TOA measurements.
Specification