Method and apparatus for interference cancellation in a rake receiver
AssigneeEricsson Inc.
InventorGregory E. Bottomley
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Abstract
Systems and methods for despreading received spread spectrum signals are described. Despreading can be performed using both channel estimates and impairment correlation estimates. Techniques for selecting delays of interest are also described, along with a despreading mechanism which saves power by operating only on delays of interest.
Claims44
A method for producing detection statistics corresponding to information symbols comprising:
- receiving a signal and creating data samples therefrom;
- correlating said data samples to a code to produce despread values;
- estimating a channel response to produce channel coefficient estimates;
- estimating impairment correlation among different delays of said received signal to produce impairment correlation estimates;
- and
- combining said despread values to produce a detection statistic using the channel coefficient estimates and the impairment correlation estimates.
A spread spectrum receiver comprising:
- a receiver to receive a signal and create data samples therefrom;
- at least one correlator to correlate said data samples to a code to produce despread values;
- a channel estimator to estimate a channel response to produce channel coefficient estimates;
- an impairment correlation estimator to estimate impairment correlation among different delays of said received signal to produce impairment correlation estimates;
- and
- a combiner to combine said despread values to produce a detection statistic using the channel coefficient estimates and the impairment correlation estimates.
A method for estimating despreading delays for a received signal comprising the steps of:
- producing sets of candidate delays;
- estimating channel responses to produce channel coefficient estimates corresponding to the sets of candidate delays;
- estimating impairment correlation among delays of the received signal corresponding to the candidate delays to produce impairment correlation estimates;
- combining the channel coefficient estimates and the impairment correlation estimates to produce metrics corresponding to the sets of candidate delays;
- and
- producing estimates of despreading delays using the metrics.
A receiver which uses estimated despreading delays to process a received signal comprising:
- a correlator placement estimator to produce sets of candidate delays;
- a channel estimator to estimate channel responses to produce channel coefficient estimates corresponding to the sets of candidate delays;
- an impairment correlation estimator to estimate impairment correlation among delays of the received signal corresponding to the candidate delays to produce impairment correlation estimates;
- a combiner to combine the channel coefficient estimates and the impairment correlation estimates to produce metrics corresponding to the sets of candidate delays;
- and
- a processor to produce estimates of despreading delays using the metrics.
Dependencies are inferred from the claim text.