Signal detection by a receiver in a multiple antenna time-dispersive system
First Claim
1. A method for compensating for time dispersion in a receiver of a wireless system that has a plurality of transmit antennas and a plurality of a receive antennas, the method comprising the steps of:
- receiving samples for each receive antenna;
determining a joint equalizer solution using channel information for at least one pairing of at least one of said transmit antennas and said receive antennas and said received samples of at least two of said receive antennas; and
applying said determined joint equalizer solution to said received samples from at least one of said receive antennas to develop equalized samples;
wherein said step of determining a joint equalizer solution is performed at least partly in the discrete frequency domain.
13 Assignments
0 Petitions
Accused Products
Abstract
In a MIMO system the bit error rate floor caused by time dispersion is reduced by employing a joint minimum mean square error (MMSE) equalizer for all of the respective transmit antenna—receive antenna pairings that are possible in the MIMO system. The resulting joint equalization compensates not only for the impact of the channel on the transmit antenna—receive antenna pairings but also for the interference of the other transmit antennas on any given receive antenna. The joint equalization outperforms simply replicating the prior art minimum mean square error (MMSE) equalizer for each transmit antenna—receive antenna pairings.
-
Citations
38 Claims
-
1. A method for compensating for time dispersion in a receiver of a wireless system that has a plurality of transmit antennas and a plurality of a receive antennas, the method comprising the steps of:
-
receiving samples for each receive antenna; determining a joint equalizer solution using channel information for at least one pairing of at least one of said transmit antennas and said receive antennas and said received samples of at least two of said receive antennas; and applying said determined joint equalizer solution to said received samples from at least one of said receive antennas to develop equalized samples; wherein said step of determining a joint equalizer solution is performed at least partly in the discrete frequency domain. - View Dependent Claims (2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 23, 24)
-
-
5. A method for compensating for time dispersion in a receiver of a wireless system that has a plurality of transmit antennas and a plurality of receive antennas, the method comprising the steps of:
-
receiving samples for each receive antenna; determining a joint equalizer solution using channel information for at least one pairing of at least one of said transmit antennas and said receive antennas and said received samples of at least two of said receive antennas; applying said determined joint equalizer solution to said received samples from at least one of said receive antennas to develop equalized samples; and despreading said equalized samples.
-
-
15. A receiver for use in a multiple-input multiple-output (MIMO) system in which a plurality of signal detectors receive signals transmitted by a plurality of signal sources, said receiver comprising:
-
a joint equalizer that develops a joint equalizer solution using channel information for at least one pairing of at least one of said signal sources and said signal detectors and received samples of at least two of said signal detectors and supplies as an output a signal that includes at least said joint equalizer solution applied to a signal received by at least one of said signal detectors; a soft bit mapper for developing soft bits from said joint equalizer output; and a despreader interposed between said joint equalizer and said soft bit mapper. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 25, 31, 32, 33, 34, 35, 36, 37)
-
-
26. A receiver for use in a multiple-input multiple-output (MIMO) system in which a plurality of signal detectors receive signals transmitted by a plurality of signal sources, said receiver comprising:
-
a joint equalizer that develops a joint equalizer solution using channel information for at least one pairing of said at least one of said signal sources and said signal detectors and received samples of at least two of said signal detectors and supplies as an output a signal that includes at least said equalizer solution applied to a signal received by at least one of said signal detectors; and a soft bit mapper for developing soft bits from said joint equalizer output; wherein said joint equalizer solution is a joint minimum mean square error (MMSE) equalizer solution and wherein said join equalizer further comprises; a first plurality of fast Fourier transform processors, each of said fast Fourier transform processors being coupled to receive a respective input corresponding to a signal received by one of said signal detectors and supplying as an output a discrete frequency domain representation thereof; a plurality of channel estimation units each of which is coupled to receive a is respective input corresponding to a signal received by one of said signal detectors which develops a channel estimate for each channel between each respective signal source and each respective signal detector; a second plurality of fast Fourier transform processors, each of said second plurality of fast Fourier transform processors coupled to receive a respective input corresponding to a channel estimate for a respective one of said channels between said signal sources and said signal detectors and supplying as an output a discrete frequency domain representation thereof; an MMSE detection per frequency bin processor coupled to receive as inputs said outputs from said first plurality of fast Fourier transform processors and from said second plurality of fast Fourier transform processors to produce a discrete frequency domain representation of an application of said joint minimum mean square error (MMSE) equalizer solution to said signals received by each of said signal detectors; and a plurality of inverse fast Fourier transform processors which convert said discrete frequency domain representation of an application of said joint minimum mean square error (MMSE) equalizer solution to the time domain. - View Dependent Claims (27)
-
-
28. A receiver for use in a multiple-input multiple-output (MIMO) system in which a plurality of signal detectors receive signals transmitted by a plurality of signal sources, said receiver comprising:
-
a joint a equalizer that develops a joint equalizer solution using channel information for at least one pairing of said at least one of said signal sources and said signal detectors and received samples of at least two of said signal detectors and supplies as an output a signal that includes at least said equalizer solution applied to a signal received by at least one of said signal detectors; and a soft bit mapper for developing soft bits from said joint equalizer output; wherein said joint equalizer solution is a joint minimum mean square error (MMSE) equalizer solution and wherein said joint equalizer further comprises; a plurality of channel estimation units each of which coupled to receive a respective input corresponding to a signal received by one of said signal detectors which develops a channel estimate for each channel between each respective signal source and each respective signal detector; a plurality of fast Fourier transform processors, each of said plurality of fast Fourier transform processors being coupled to receive a respective input corresponding to a channel estimate for a respective one of said channels between said signal sources and said signal detectors and supplying as an output a discrete frequency domain representation thereof; an MMSE tap weight calculator coupled to receive as inputs said outputs from said plurality of fast Fourier transform processors to produce a discrete frequency domain representation of a joint minimum mean square error (MMSE) equalizer solution to said signals received by each of said signal detectors; a plurality of inverse fast Fourier transform processors which convert said discrete frequency domain representation of a joint minimum mean square error (MMSE) equalizer solution to matrices of filter coefficients in the time domain; and a matrix finite impulse response (FIR) fitter coupled to apply said matrices of filter coefficients in the time domain to said signals received by said signal detectors. - View Dependent Claims (29, 30)
-
-
38. A receiver for use in a multiple-input multiple-output (MIMO) system in which a plurality of receive antennas receive signals transmitted by a plurality of transmit antennas, said receiver comprising:
-
means for (i) developing a joint equalizer solution using channel information for at least one pairing of at least one of said transmit antennas and said receive antennas and said received samples of at least two of said receive antennas, said joint equalizer solution being developed at least partly in a frequency domain, and (ii) supplying as an output a signal that includes at least said joint equalizer solution applied to signal received by at least one of said receive antennas; and means for developing soft bits from said output signal.
-
Specification