Interference Suppression for CDMA Systems
First Claim
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1. A CDMA receiver, comprising:
- a signal-to-interference-and-noise ratio (SINR)-estimation module in a receiver, the SINR estimation module configured for producing one or more SINR estimates corresponding to one or more subchannels of a received multipath signal;
a thresholding module configured for comparing each of the one or more SINR estimates to a threshold to determine whether to employ a weighted soft decision or a hard decision;
a companding module configured for generating the weighted soft decision or the hard decision determined by the thresholding module for each of the one or more SINR estimates; and
a suppressor configured for producing at least one interference-suppressed signal from one or more of the soft decisions or hard decisions generated by the companding module.
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Abstract
Interference is cancelled from a baseband signal by synthesizing interference from estimated symbols in interfering subchannels. The estimated symbols are hard-coded, soft weighted, or zeroed, depending on the value of an estimated pre-processed signal-to-interference-and-noise ratio (SINR) in each subchannel in order to maximize a postprocessed SINR. The estimated pre-processed SINR is obtained from averages of estimated symbol energies and estimated noise variances, or from related statistical procedures.
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Citations
56 Claims
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1. A CDMA receiver, comprising:
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a signal-to-interference-and-noise ratio (SINR)-estimation module in a receiver, the SINR estimation module configured for producing one or more SINR estimates corresponding to one or more subchannels of a received multipath signal; a thresholding module configured for comparing each of the one or more SINR estimates to a threshold to determine whether to employ a weighted soft decision or a hard decision; a companding module configured for generating the weighted soft decision or the hard decision determined by the thresholding module for each of the one or more SINR estimates; and a suppressor configured for producing at least one interference-suppressed signal from one or more of the soft decisions or hard decisions generated by the companding module. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of receiving a CDMA signal, comprising:
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producing in a receiver one or more SINR estimates corresponding to one or more subchannels of a received multipath signal; comparing each of the one or more SINR estimates to a predetermined threshold for determining whether to employ a weighted soft decision or a hard decision; generating the weighted soft decision or the hard decision determined for each of the one or more SINR estimates to produce at least one interference-symbol estimate; and producing at least one interference-suppressed signal from a received baseband signal and the at least one interference-symbol estimate. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A CDMA receiver, comprising:
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a means for determining an SINR estimate for each of one or more subchannels of a received signal; a means for determining whether to use weighted soft decisions or hard decisions for each of the one or more subchannel; a means for generating the weighted soft decisions or hard decisions determined for each of the one or more SINR estimates; and a means for producing an interference-suppressed signal from a received baseband signal and at least one interference-symbol estimate, wherein each of the at least one interference-symbol estimate comprises a hard decision or a weighted soft decision of a corresponding symbol estimate. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55)
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56. A CDMA receiver, comprising:
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a signal-to-interference-and-noise ratio (SINR)-estimation module in a receiver, the SINR estimation module configured for producing one or more SINR estimates corresponding to one or more subchannels of a received multipath signal; a thresholding module configured for comparing each of the one or more SINR estimates to a threshold to determine whether to employ a weighted soft decision or a hard decision; and a companding module configured for generating the weighted soft decision or the hard decision determined by the thresholding module for each of the one or more SINR estimates.
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Specification