Patent US5506861A successfully refreshed from Google Patents.
US5506861A
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System and method for joint demodulation of CDMA signals
Assignee: Ericsson Inc
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Filing: 1993-11-22
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Granted: 1996-04-09
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Expires: 2013-11-22
Abstract
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.
Inventors
- 👤 Gregory E. Bottomley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:38
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/69; H04B1/707; H04B1/7073; H04B1/7085; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03178; H04L25/03331; H04B1/7097; H04B1/711; H04B7/00; H04B7/14; H04B7/15; H04B7/204; H04B7/216; H04L25/0202; H04L25/0204; H04L25/0212; H04L25/0216; H04L25/0222
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
107 words
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, and means for combining said real parts of said products to determine at least one transmitted information symbol sequence.
Claim 2
Dependent Claim
107 words
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, and means for combining said real parts of said products to determine at least one transmitted information symbol sequence.
Claim 3
Dependent Claim
23 words
The receiver of claim 1, wherein said means for estimating further comprises: means for tracking time variations of said multipath channel tap coefficients.
Claim 4
Dependent Claim
24 words
The receiver of claim 1, wherein said means for combining uses a Viterbi algorithm to determine said at least one transmitted information symbol sequence.
Claim 5
Dependent Claim
28 words
The receiver of claim 1, wherein said received signal comprises a plurality of CDMA signals which are jointly demodulated to determine a plurality of transmitted information symbol sequences.
Claim 6
Dependent Claim
88 words
A receiver for jointly demodulating a plurality of CDMA signals from a received signal comprising: 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.
Claim 7
Dependent Claim
88 words
A receiver for jointly demodulating a plurality of CDMA signals from a received signal comprising: 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.
Claim 8
Dependent Claim
22 words
The receiver of claim 5, wherein said estimating means further comprises: means for tracking time variations of said multipath channel tap coefficients.
Claim 9
Independent Claim
96 words
A method for demodulating at least one CDMA signal from a received signal comprising the steps of: 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.
Claim 10
Independent Claim
96 words
A method for demodulating at least one CDMA signal from a received signal comprising the steps of: 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.
Claim 11
Dependent Claim
24 words
The method of claim 7, wherein said step of estimating further comprises the step of: tracking time variations of said multipath channel tap coefficients.
Claim 12
Dependent Claim
29 words
The method of claim 7, wherein said step of combining further comprises the step of: using a Viterbi algorithm to determine said at least one transmitted information symbol sequence.
Claim 13
Dependent Claim
105 words
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 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.
Claim 14
Dependent Claim
105 words
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 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.
Claim 15
Dependent Claim
25 words
The receiver of claim 10, wherein said means for decorrelating uses only correlations corresponding to one symbol period of said at least one CDMA signal.
Claim 16
Independent Claim
97 words
A method for demodulating at least one CDMA signal comprising the steps of: 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.
Claim 17
Independent Claim
97 words
A method for demodulating at least one CDMA signal comprising the steps of: 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.
Claim 18
Dependent Claim
25 words
The method of claim 12, wherein said step of decorrelating uses only correlations corresponding to one symbol period of said at least one CDMA signal.
Claim 19
Dependent Claim
28 words
The receiver of claim 10, wherein said received signal comprises a plurality of CDMA signals which are jointly demodulated to determine a plurality of transmitted information symbol sequences.
Claim 20
Dependent Claim
29 words
The method of claim 12, wherein said received signal comprises a plurality of CDMA signals and said step of decorrelating solves for a plurality of transmitted information symbol sequences.
Claim 21
Dependent Claim
16 words
The receiver of claim 10, wherein said means for decorrelating further comprises means for noise whitening.
Claim 22
Dependent Claim
100 words
A receiver for demodulating at least one CDMA signal in a multipath environment comprising: 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.
Claim 23
Dependent Claim
100 words
A receiver for demodulating at least one CDMA signal in a multipath environment comprising: 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.
Claim 24
Dependent Claim
30 words
The receiver of claim 17, wherein said means for deciding the information symbol sequences uses only correlations corresponding to a single symbol period of the at least one CDMA signal.
Claim 25
Dependent Claim
23 words
The receiver of claim 17, wherein said means for estimating further comprises: means for tracking time variations in said multipath channel tap coefficients.
Claim 26
Independent Claim
89 words
A method for demodulating at least one CDMA signal comprising the steps of: 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.
Claim 27
Independent Claim
89 words
A method for demodulating at least one CDMA signal comprising the steps of: 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.
Claim 28
Dependent Claim
35 words
The method of claim 20, wherein said step of deciding the information bit sequences further comprises the step of: using only correlations corresponding to a single symbol period of said at least one CDMA signal.
Claim 29
Dependent Claim
24 words
The method of claim 20, wherein said step of estimating further comprises the step of: tracking time variations in said multipath channel tap coefficients.
Claim 30
Dependent Claim
105 words
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 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.
Claim 31
Dependent Claim
105 words
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 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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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-04-09 | 1999-10-09 | 2000-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-04-09 | 2003-10-09 | 2004-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-04-09 | 2007-10-09 | 2008-04-09 | $7700.00 | Window Closed / Lapsed |