Velocity responsive time tracking
First Claim
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1. A method of providing velocity responsive tracking of a timing reference in a signal received by a wireless communications device (WCD), comprising the steps of:
- estimating the velocity of the WCD;
determining a tracking speed of a filter, the tracking speed corresponding to the estimated velocity; and
filtering a timing error signal with the filter to produce a control signal that controls the timing of a synchronization clock.
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Abstract
The velocity of a wireless communications device (WCD) is estimated. In response to this estimated velocity, a tracking speed of a filter is determined that corresponds to the estimated velocity. The filter filters a timing error signal to produce a control signal that controls the timing of a synchronization clock. This synchronization clock may be a finger clock that controls the timing of a pseudonoise (PN) sequence generator configured for despreading a pilot symbol sequence.
28 Citations
35 Claims
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1. A method of providing velocity responsive tracking of a timing reference in a signal received by a wireless communications device (WCD), comprising the steps of:
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estimating the velocity of the WCD;
determining a tracking speed of a filter, the tracking speed corresponding to the estimated velocity; and
filtering a timing error signal with the filter to produce a control signal that controls the timing of a synchronization clock. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A system for providing velocity responsive tracking of a timing reference in a signal received by a wireless communications device (WCD), comprising:
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a velocity estimator that estimates the velocity of the WCD; and
a filter having a tracking speed that corresponds to the estimated velocity, wherein said filter filters a timing error signal to produce a control signal that controls the timing of a synchronization clock. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A time tracking loop filter that filters a timing error signal to produce a control signal for controlling the timing of a synchronization clock in a wireless communications device (WCD), comprising:
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a velocity to gain translation module that receives an estimated velocity of the WCD and produces a gain signal that corresponds to the estimated velocity; and
a filter stage having a tracking speed that is determined by the value of the gain signal, wherein the tracking speed determines the extent that fluctuations in the input signal are passed to the control signal.
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24. A system for providing velocity responsive tracking of a timing reference in a signal received by a wireless communications device (WCD), comprising:
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means for estimating the velocity of the WCD;
means for determining a tracking speed of a filter, the tracking speed corresponding to the estimated velocity; and
means for filtering a timing error signal with the filter to produce a control signal that controls the timing of a synchronization clock. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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Specification