Reduced complexity soft value generation for multiple-input multiple-output (MIMO) joint detection generalized RAKE (JD-GRAKE) receivers
First Claim
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1. A method of processing a received composite communications signal that includes two or more signals of interest, the method comprising the steps of:
- generating combining weights as a function of impairment correlations for despread values of the input signals;
combining the despread values according to the combining weights; and
,jointly detecting the signals of interest based on the combined despread values and mixing between symbols in a detection metric;
wherein said step of jointly detecting the signals of interest further comprises jointly demodulating the combined despread values to obtain soft values representing estimates of detected bits in the signals of interest;
wherein said step of jointly demodulating the combined despread values to obtain soft values representing estimates of detected bits in the signals of interest further comprises generating soft values by a non-exhaustive tree search technique;
wherein said step of generating soft values by a non-exhaustive tree search technique further comprises the steps of;
generating a causal factorization of a s-parameter matrix;
generating first symbol estimates of a transmitted symbol vector;
generating a reduced set of cumulative metrics based on the causal factorization of the s-parametermatrix and first symbol estimates of the transmitted symbol vector by producing a set of cumulative metrics using an m-algorithm processor; and
generating soft bit values based on the set of cumulative metrics produced by the m-algorithm processor.
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Abstract
A receiver includes a receiver circuit that decodes multiple signals of interest contained in a composite receive signal. The receiver comprises at least one Generalized RAKE combining circuit and a joint demodulation circuit and generates a detected signal at an output. The joint demodulation circuit contains a reduced search soft value generator circuit and generates soft bit values that represent coded bits received from the transmitter.
65 Citations
26 Claims
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1. A method of processing a received composite communications signal that includes two or more signals of interest, the method comprising the steps of:
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generating combining weights as a function of impairment correlations for despread values of the input signals; combining the despread values according to the combining weights; and
,jointly detecting the signals of interest based on the combined despread values and mixing between symbols in a detection metric; wherein said step of jointly detecting the signals of interest further comprises jointly demodulating the combined despread values to obtain soft values representing estimates of detected bits in the signals of interest; wherein said step of jointly demodulating the combined despread values to obtain soft values representing estimates of detected bits in the signals of interest further comprises generating soft values by a non-exhaustive tree search technique; wherein said step of generating soft values by a non-exhaustive tree search technique further comprises the steps of; generating a causal factorization of a s-parameter matrix; generating first symbol estimates of a transmitted symbol vector; generating a reduced set of cumulative metrics based on the causal factorization of the s-parameter matrix and first symbol estimates of the transmitted symbol vector by producing a set of cumulative metrics using an m-algorithm processor; and generating soft bit values based on the set of cumulative metrics produced by the m-algorithm processor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A receiver for processing a received composite communications signal that includes two or more signals of interest, said receiver comprising:
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a plurality of correlator banks and a combiner for a generating combining weights as a function of impairment correlations for despread values of the input signals and for combining the despread values according to the combining weights; and a reduced search soft value generator for jointly detecting the signals of interest based on the combined despread values and mixing between symbols in a detection metric; wherein said reduced search soft value generator jointly detects the signals of interest by jointly demodulating the combined despread values to obtain soft values representing estimates of detected bits in the signals of interest; and
,wherein said reduced search soft value generator uses a non-exhaustive tree search technique to generate the soft values by performing the following steps; generating a causal factorization of a s-parameter matrix; generating first symbol estimates of a transmitted symbol vector; generating a reduced set of cumulative metrics based on the causal factorization of the s-parameter matrix and first symbol estimates of the transmitted symbol vector by producing a set of cumulative metrics using an m-algorithm processor; and generating soft bit values based on the set of cumulative metrics produced by the m-algorithm processor. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A wireless communication system, comprising:
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a base station for transmitting a composite communications signal; a mobile terminal for receiving and processing the composite communications signal that includes two or more signals of interest by performing the following steps; generating combining weights as a function of impairment correlations for despread values of the input signals; combining the despread values according to the combining weights; and
,jointly detecting the signals of interest based on the combined despread values and mixing between symbols in a detection metric, wherein said step of jointly detecting the signals of interest further comprises jointly demodulating the combined despread values to obtain soft values representing estimates of detected bits in the signals of interest; wherein said step of jointly demodulating the combined despread values to obtain soft values representing estimates of detected bits in the signals of interest comprises generating soft values by a non-exhaustive tree search technique; wherein said step of generating soft values by a non-exhaustive tree search technique comprises the steps of; generating a causal factorization of a s-parameter matrix; generating first symbol estimates of a transmitted symbol vector; generating a reduced set of cumulative metrics based on the causal factorization of the s-parameter matrix and first symbol estimates of the transmitted symbol vector by producing a set of cumulative metrics using an m-algorithm processor; and
,generating soft bit values based on the set of cumulative metrics produced by the m-algorithm processor. - View Dependent Claims (20)
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21. A mobile terminal comprising:
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a plurality of receive antennas for receiving a composite communications signal; and a receiver including; a plurality of correlator banks and a combiner for a generating combining weights as a function of impairment correlations for despread values of the input signals and for combining the despread values according to the combining weights; and a reduced search soft value generator for jointly detecting the signals of interest based on the combined despread values and mixing between symbols in a detection metric, wherein said reduced search soft value generator jointly detects the signals of interest by jointly demodulating the combined despread values to obtain soft values representing estimates of detected bits in the signals of interest; and
,wherein said reduced search soft value generator uses a non-exhaustive tree search technique to generate the soft values by performing the following steps; generating a causal factorization of a s-parameter matrix; generating first symbol estimates of a transmitted symbol vector; generating a reduced set of cumulative metrics based on the causal factorization of the s-parameter matrix and first symbol estimates of the transmitted symbol vector by producing a set of cumulative metrics using an m-algorithm processor; and generating soft bit values based on the set of cumulative metrics produced by the m-algorithm processor. - View Dependent Claims (22, 23)
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24. A base station comprising:
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a plurality of transmit antennas for transmitting a composite communications signal to a mobile terminal that includes; a plurality of receive antennas for receiving a composite communications signal; and a receiver including; a plurality of correlator banks and a combiner for a generating combining weights as a function of impairment correlations for despread values of the input signals and for combining the despread values according to the combining weights; and a reduced search soft value generator for jointly detecting the signals of interest based on the combined despread values and mixing between symbols in a detection metric; wherein said reduced search soft value generator jointly detects the signals of interest by jointly demodulating the combined despread values to obtain soft values representing estimates of detected bits in the signals of interest; and
,wherein said reduced search soft value generator uses a non-exhaustive tree search technique to generate the soft values by performing the following steps; generating a causal factorization of a s-parameter matrix; generating first symbol estimates of a transmitted symbol vector; generating a reduced set of cumulative metrics based on the causal factorization of the s-parameter matrix and first symbol estimates of the transmitted symbol vector by producing a set of cumulative metrics using an m-algorithm processor; and generating soft bit values based on the set of cumulative metrics produced by the m-algorithm processor. - View Dependent Claims (25, 26)
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Specification