Methods and apparatus for detection of signal timing
First Claim
1. An apparatus for determining the timing of a received signal, the received signal including one or more time-delayed versions of a reference signal traveling over respective different signal paths, the apparatus comprising:
- a correlator configured to iteratively correlate the received signal with the reference signal to produce a correlated signal;
a chip-level energy extractor configured to emphasize the correlated signal in peak chips containing signal peaks by reducing the amplitude of the correlated signal in other chips, wherein the signal peaks correspond to potential signal paths of the received signal;
a sample-level energy extractor configured to emphasize the correlated signal in peak samples in the peak chips by reducing the amplitude of other samples in the peak chips; and
a processor configured to iteratively modify the received signal supplied to the correlator until the processor determines that the correlated signal includes a signal peak corresponding to a direct path of the received signal, the direct path providing the timing of the received signal, wherein in each iteration, the processor regenerates the reference signal corresponding to at least a greatest signal peak in the correlated signal and modifies the received signal supplied to the correlator to remove contributions from the regenerated reference signals, such that the correlated signal in successive iterations excludes contributions from signals determined in previous iterations not to correspond to the direct path.
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Abstract
A technique is described for determining the timing of a received signal that includes one or more time-delayed versions of a reference signal traveling over respective different signal paths. The technique includes correlating the received signal with the reference signal to produce a correlated signal; determining whether the correlated signal includes a signal peak that corresponds to the direct path of the received signal; and iterative repeating these operations until a signal peak is determined to correspond to the direct path of the received signal. In each successive iteration, the reference signal corresponding to at least the greatest signal peak in the correlated signal is regenerated, and contributions from each regenerated reference signal are removed from the received signal prior to correlating the received signal in the next iteration.
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Citations
17 Claims
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1. An apparatus for determining the timing of a received signal, the received signal including one or more time-delayed versions of a reference signal traveling over respective different signal paths, the apparatus comprising:
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a correlator configured to iteratively correlate the received signal with the reference signal to produce a correlated signal; a chip-level energy extractor configured to emphasize the correlated signal in peak chips containing signal peaks by reducing the amplitude of the correlated signal in other chips, wherein the signal peaks correspond to potential signal paths of the received signal; a sample-level energy extractor configured to emphasize the correlated signal in peak samples in the peak chips by reducing the amplitude of other samples in the peak chips; and a processor configured to iteratively modify the received signal supplied to the correlator until the processor determines that the correlated signal includes a signal peak corresponding to a direct path of the received signal, the direct path providing the timing of the received signal, wherein in each iteration, the processor regenerates the reference signal corresponding to at least a greatest signal peak in the correlated signal and modifies the received signal supplied to the correlator to remove contributions from the regenerated reference signals, such that the correlated signal in successive iterations excludes contributions from signals determined in previous iterations not to correspond to the direct path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 13, 14, 15)
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9. A method for determining the timing of a received signal, the received signal including one or more time-delayed versions of a reference signal traveling over respective different signal paths, the method comprising:
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(a) correlating the received signal with the reference signal to produce a correlated signal; (b) extracting energy of the correlated signal at a chip level to emphasize the correlated signal in peak chips containing signal peaks, wherein the signal peaks correspond to potential signal paths of the received signal; (c) extracting energy of the correlated signal at a sample level to emphasize the correlated signal in peak samples in the peak chips; (d) determining whether a signal peak of the correlated signal corresponds to the direct path of the received signal, the direct path providing the timing of the received signal; and (e) iteratively repeating (a) through (d) until a signal peak is determined to correspond to the direct path of the received signal, wherein each successive iteration includes;
regenerating the reference signal corresponding to at least a greatest signal peak in the correlated signal; and
eliminating from the received signal contributions from each regenerated reference signal, such that the correlated signal in successive iterations excludes contributions from signals determined in previous iterations not to correspond to the direct path. - View Dependent Claims (10, 11, 16, 17)
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12. An apparatus for determining the timing of a received signal, the received signal including one or more time-delayed versions of a reference signal traveling over respective different signal paths, the apparatus comprising:
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means for iteratively correlating the received signal with the reference signal to produce a correlated signal; means for emphasizing the correlated signal in peak chips containing signal peaks by reducing the amplitude of the correlated signal in other chips, wherein the signal peaks correspond to potential signal paths of the received signal; means for emphasizing the correlated signal in peak samples in the peak chips by reducing the amplitude of other samples in the peak chips; means for determining whether the correlated signal includes a signal peak corresponding to a direct path of the received signal, the direct path providing the timing of the received signal, wherein correlation iterations cease once a signal peak is determined to correspond to the direct path; means for regenerating, in each iteration, the reference signal corresponding to at least a greatest signal peak in the correlated signal in response to no signal peak being determined to correspond to the direct path; and means for modifying, in each iteration, the received signal to be correlated to remove contributions from the regenerated reference signals, such that the correlated signal in successive iterations excludes contributions from signals determined in previous iterations not to correspond to the direct path.
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Specification