United States Patent 7,724,817
Pietraski , et al. May 25, 2010
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Method and apparatus for estimating the step-size of an adaptive equalizer
Abstract
A step-size estimator for controlling the step-size of an adaptive equalizer incorporated in a transceiver (e.g., a wireless transmit/receive unit (WTRU)). The step-size estimator updates at least one adaptive equalizer tap used by the adaptive equalizer based on an apparent speed of a channel established between the transceiver and another transceiver. The step-size estimator includes a speed estimator, a signal-to-noise ratio (SNR) averager and a step-size mapping unit. The speed estimator is used to estimate the apparent speed of the channel (i.e., the observed and/or measured rate of change of the channel impulse response). The SNR averager generates a common pilot channel (CPICH) SNR estimate. The step-size mapping unit uses the speed estimate and the CPICH SNR estimate to generate a step-size parameter, .mu., and a filter taps leakage factor parameter, .alpha., used by the adaptive equalizer to update the filter tap coefficient.
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Inventors: Pietraski; Philip J. (Huntington Station, NY), Beluri; Mihaela C. (Huntington, NY), Demir; Alpaslan (East Meadow, NY)
Assignee: InterDigital Technology Corporation (Wilmington, DE)
Appl. No.: 12/360,171
Filed: January 27, 2009
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Related U.S. Patent Documents
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Application Number Filing Date Patent Number Issue Date
11238469 Sep., 2005 7496138
60625869 Nov., 2004
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Current U.S. Class: 375/232
Current International Class: H03H 7/30 (20060101)
Field of Search: 375/229,230,232
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