System and method for joint demodulation of CDMA signals
First Claim
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1. A receiver for demodulating at least one CDMA signal from a received signal comprising:
- means for producing data samples from said received signal,means for collecting said data samples into blocks of complex data samples,means for aperiodically correlating said blocks of data samples with shifts of at least one known signature sequence,means for selecting a predetermined number of said aperiodic correlations,means for estimating multipath channel tap coefficients,means for forming real parts of products of said selected aperiodic correlations with said multipath channel tap coefficients, andmeans for combining said real parts of said products to determine at least one transmitted information symbol sequence.
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Abstract
Methods and systems for jointly demodulating CDMA signals are presented. The disclosed methods and systems provide, among other advantages, for accurate demodulation of such signals in multipath, time-dispersion environments. Single signal or multiple signal demodulation, with or without taking intersymbol interference into account can be accomplished according to the present invention.
125 Citations
23 Claims
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1. A receiver for demodulating at least one CDMA signal from a received signal comprising:
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means for producing data samples from said received signal, means for collecting said data samples into blocks of complex data samples, means for aperiodically correlating said blocks of data samples with shifts of at least one known signature sequence, means for selecting a predetermined number of said aperiodic correlations, means for estimating multipath channel tap coefficients, means for forming real parts of products of said selected aperiodic correlations with said multipath channel tap coefficients, and means for combining said real parts of said products to determine at least one transmitted information symbol sequence. - View Dependent Claims (2, 3, 4)
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5. A receiver for jointly demodulating a plurality of CDMA signals from a received signal comprising:
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means for producing data samples from said received signal, means for forming correlations of said data samples with at least one known signature sequence, means for selecting a predetermined number of said correlations, means for estimating multipath channel tap coefficients, means for forming real parts of products of said selected correlations with said multipath channel tap coefficients, and means for combining said products in a metric processor to determine transmitted information symbol sequences. - View Dependent Claims (6)
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7. A method for demodulating at least one CDMA signal from a received signal comprising the steps of:
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producing data samples from said received signal, collecting said data samples into blocks of complex data samples, aperiodically correlating said blocks of data samples with shifts of at least one known signature sequence, selecting a predetermined number of said aperiodic correlations, estimating multipath channel tap coefficients, forming real parts of products of said selected aperiodic correlations with said multipath channel tap coefficients, and combining said real parts of said products to determine at least one transmitted information symbol sequence. - View Dependent Claims (8, 9)
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10. A receiver for demodulating at least one CDMA signal from a received signal comprising:
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means for producing data samples from said received signal, means for correlating said data samples to at least one known signature sequence to produce a plurality of correlations for each signature sequence, means for selecting one of said plurality of said correlations for each signal ray of each of said at least one CDMA signals, means for estimating multipath channel tap coefficients, and means for decorrelating said at least one CDMA signal using said selected correlations and said channel tap coefficients to solve for at least one transmitted information symbol sequence. - View Dependent Claims (11, 14, 16)
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12. A method for demodulating at least one CDMA signal comprising the steps of:
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producing data samples from said at least one CDMA signal, correlating said data samples to at least one known signature sequence to produce a plurality of correlations for each signature sequence, selecting one of said plurality of said correlations for each signal ray of each of said at least one CDMA signals, estimating multipath channel tap coefficients, and decorrelating said at least one CDMA signal using said selected correlations and said channel tap coefficients to solve for at least one transmitted information symbol sequence. - View Dependent Claims (13, 15)
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17. A receiver for demodulating at least one CDMA signal in a multipath environment comprising:
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means for producing data samples from a received signal, means for correlating said data samples to at least one known signature sequence to produce a plurality of correlations for each signature sequence, means for selecting one of said plurality of said correlations for each signal ray of each of said at least one CDMA signals, means for estimating multipath channel tap coefficients, and means for deciding at least one transmitted information symbol sequence using a Viterbi processor, said selected correlation values and said channel tap coefficients. - View Dependent Claims (18, 19)
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20. A method for demodulating at least one CDMA signal comprising the steps of:
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producing data samples from a received signal, correlating said data samples to at least one known signature sequence to produce a plurality of correlations for each signature sequence, selecting one of said plurality of said correlations for each signal ray of each of said at least one CDMA signals, estimating multipath channel tap coefficients, and deciding at least one transmitted information symbol sequence using a Viterbi processor, said selected correlation values and said channel tap coefficients. - View Dependent Claims (21, 22)
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23. A receiver for demodulating at least one CDMA signal from a received signal comprising:
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means for producing data samples from said received signal, means for collecting said data samples into blocks of complex data samples, means for estimating multipath channel tap coefficients, means for forming a plurality of blocks of predicted received data samples using said channel tap coefficients, means for summing a magnitude square of a difference between said block of received data samples and said blocks of predicted received values to form a plurality of block metrics, and means for combining said block metrics to determine at least one transmitted information data sequence.
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Specification