Method and apparatus for diversity reception of time-dispersed signals
First Claim
1. A receiver for providing diversity reception comprised of:
- (a) correlating means for generating;
(i) a first correlation signal by digitally correlating a first received sampled time-dispersed signal against a known reference sequence; and
(ii) a second correlation signal by digitally correlating a second received sampled time-dispersed signal against the known reference sequence;
(b) re-aligning means, operably coupled to the correlating means, for generating;
(i) a first aligned signal by coherently re-aligning the first time-dispersed signal to the reference sequence by using at least the first correlation signal; and
(ii) a second aligned signal by coherently re-aligning the second time-dispersed signal to the reference sequence by using at least the second correlation signal; and
(c) signal generation means, operably coupled to re-aligning means, for generating a digital output signal derived from the first and second aligned signals.
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Abstract
A method and appartus for diversity reception in a communication system wherein at least a dual branch receiver is provided with a stored replica of expected reference information that is correlated with the received time-dispersed signals to obtain an estimate of the transmission channel'"'"'s impulse response as seen by each branch, and determine, among other things, phase error between the branch local oscillators and the time-dispersed signals. Matched filters are constructed which then coherently align the time-dispersed signals from each branch with that branch'"'"'s local oscillator, also constituting the first part of the equalization. The diversity processing stage may perform bit by bit selection on the re-aligned signals, maximal ratio combining of the re-aligned signals, or equal gain combining of the re-aligned signals, following each by a sequence estimation which uses similarly selected or combined channel distortion compensation parameters to complete the equalization process on the new signal. In digital modulated carrier systems, providing expected reference information eliminates the neeed for carrier recovery feedback for each branch while performing part of the equalization process.
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Citations
27 Claims
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1. A receiver for providing diversity reception comprised of:
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(a) correlating means for generating; (i) a first correlation signal by digitally correlating a first received sampled time-dispersed signal against a known reference sequence; and (ii) a second correlation signal by digitally correlating a second received sampled time-dispersed signal against the known reference sequence; (b) re-aligning means, operably coupled to the correlating means, for generating; (i) a first aligned signal by coherently re-aligning the first time-dispersed signal to the reference sequence by using at least the first correlation signal; and (ii) a second aligned signal by coherently re-aligning the second time-dispersed signal to the reference sequence by using at least the second correlation signal; and (c) signal generation means, operably coupled to re-aligning means, for generating a digital output signal derived from the first and second aligned signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A receiver for providing diversity reception comprised of:
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(a) correlating means for generating; (i) a first correlation signal by digitally correlating a first received digital time-dispersed signal against a known reference sequence; (ii) a second correlation signal by digitally correlating a second received digital time-dispersed signal against the known reference sequence; (iii) first s-parameters associated with the first received time-dispersed signal, the first s-parameters being derived from an estimated channel impulse response from a first receiver branch through which the first received digital time-dispersed signal was received and a matched filter impulse response from the first receiver branch; and (iv) second s-parameters associated with the second received time-dispersed signal, the second s-parameters being derived from an estimated channel impulse response from a second receiver branch through which the second received digital time-dispersed signal was received and a matched filter impulse response from the second receiver branch; (b) re-aligning means, operably coupled to the correlating means, for generating; (i) a first aligned symbol sequence by coherently re-aligning the first received signal to the reference sequence by using at least the first correlation signal; and (ii) a second aligned symbol sequence by coherently re-aligning the second received signal to the reference sequence by using at least the second correlation signal; and (c) signal generation means, operably coupled to re-aligning means, for generating a digital output signal derived from the first and second aligned symbol sequences and the first and second s-parameters.
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15. A method for providing diversity reception comprising:
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(a) generating a first correlation signal by digitally correlating a first received sampled time-dispersed signal against a known reference sequence; (b) generating a second correlation signal by digitally correlating a second received sampled time-dispersed signal against the known reference sequence; (c) generating a first aligned signal by coherently re-aligning the time-dispersed signal to the reference sequence by using at least the first correlation signal; (d) generating a second aligned signal by coherently re-aligning the second time-dispersed signal to the reference sequence by using at least the second correlation signal; and (e) generating a digital output signal derived from the first aligned signal and the second aligned signal. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method for providing diversity reception comprising:
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(a) generating a first correlation signal by digitally correlating a first received time-dispersed digital signal against a stored known reference sequence; (b) generating a second correlation signal by digitally correlating a second received time-dispersed digital signal against the stored known reference sequence; (c) generating first s-parameters derived from a channel impulse response of a first receiver branch through which the first received time-dispersed signal was received and a matched filter impulse response of the first receiver branch; (d) generating second s-parameters derived from a channel impulse response of a second receiver branch through which the second received time-dispersed signal was received and a matched filter impulse response of the second receiver branch; (e) generating a first aligned signal by coherently re-aligning the first time-dispersed digital signal to the reference sequence by using at least the first correlation signal; (f) generating a second aligned signal by coherently re-aligning the second time-dispersed digital signal to the reference sequence by using at least the second correlation signal; and (g) generating a digital output signal by; (i) sampling symbols from each of the aligned signals; (ii) generating an array of symbol samples through bit by bit selection of appropriate symbol samples from at least one of the aligned signals based on absolute values of at least one symbol sample from each aligned signal; (iii) counting the number of symbol samples selected from each aligned signal; and (iv) providing a sequence estimator with the symbol sample array and the s-parameters associated with the receiver branch whose aligned signal which was derived from a time-dispersed signal received by the receiver branch having a desired number of counted symbol samples. - View Dependent Claims (27)
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Specification