Method and apparatus for adjusting delay in systems with time-burst pilot and fractionally spaced equalizers
First Claim
1. A method for determining a current delay offset of a fractionally spaced equalizer, said method comprising steps of:
- determining an arrival time from a first and a second Rake receiver fingers;
determining a difference between said arrival time and a previous delay offset of said fractionally spaced equalizer; and
modifying said current delay offset of said fractionally spaced equalizer by an incremental delay offset when said difference is greater than or equal to one tap spacing.
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Accused Products
Abstract
A weighted mean arrival time determines a delay offset of a fractionally spaced equalizer. The weighted mean arrival time is determined using path arrival times and energies from a Rake receiver. The difference between a weighted mean arrival time and a current delay offset is set to a difference X, in units of the equalizer tap spacing. If the difference X is greater than or equal to 1 or less than or equal to −1, then the current delay offset is updated by an incremental delay offset and the equalizer filter coefficients are shifted by a number of tap spacings. Otherwise, the current delay offset is not updated and the filter coefficients of the fractionally spaced equalizer are not shifted. Adaptation of the filter coefficients and updates of the delay offset of the equalizer occur only during pilot bursts so as to minimize adaptation transients.
22 Citations
27 Claims
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1. A method for determining a current delay offset of a fractionally spaced equalizer, said method comprising steps of:
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determining an arrival time from a first and a second Rake receiver fingers; determining a difference between said arrival time and a previous delay offset of said fractionally spaced equalizer; and modifying said current delay offset of said fractionally spaced equalizer by an incremental delay offset when said difference is greater than or equal to one tap spacing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A receiver in a wireless communications system, said receiver comprising:
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a sample buffer coupled to a first and a second Rake receiver fingers; and a weighted mean time tracking module coupled to said first and said second Rake receiver fingers and said sample buffer, and wherein said weighted mean time tracking module is configured to set a current delay offset of a fractionally spaced equalizer in said receiver to a weighted mean arrival time. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A digital signal processing apparatus to determine a current delay offset of a fractionally spaced equalizer, said processing apparatus comprising:
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a storage; and a digital signal processor coupled to said storage and used to interpret digital signals by; determining a statistically derived arrival time from a first and a second Rake receiver finger; determining a difference between said statistically derived arrival time and a previous delay offset of said fractionally spaced equalizer; and modifying said current delay offset of said fractionally spaced equalizer by an incremental delay offset when said difference is greater than or equal to one tap spacing.
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27. A receiver in a wireless communications system, said receiver comprising:
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a buffering means coupled to a first and a second Rake receiver means; and a weighted mean time tracking means coupled to said first and said second Rake receiver means and said buffer means, wherein said weighted mean time tracking means is configured to set a current delay offset of a fractionally spaced equalizer means in said receiver to a weighted mean arrival time.
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Specification