Multiple input multiple output multicarrier communication system and methods with quantized beamforming feedback
First Claim
Patent Images
1. A multicarrier transmitter comprising:
- transmit subcarrier beamformers to apply quantized transmit beamforming coefficients to a plurality of symbol-modulated subcarriers in a signal path before an inverse Fourier transform (IFFT) is performed on the symbol-modulated subcarriers, wherein the quantized transmit beamforming coefficients comprise predetermined numbers of bits for the subcarriers indicating amounts to weight an amplitude and shift a phase of an associated one or more subcarriers.
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Abstract
A multicarrier receiver generates a quantized transmit beamformer matrix ({tilde over (V)}) for each subcarrier of a multicarrier communication channel for use by a multicarrier transmitting station. The multicarrier receiver applies a corrected receiver beamformer matrix (ŨH) to received subcarriers signals generated by signals received from the transmitting station.
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Citations
35 Claims
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1. A multicarrier transmitter comprising:
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transmit subcarrier beamformers to apply quantized transmit beamforming coefficients to a plurality of symbol-modulated subcarriers in a signal path before an inverse Fourier transform (IFFT) is performed on the symbol-modulated subcarriers, wherein the quantized transmit beamforming coefficients comprise predetermined numbers of bits for the subcarriers indicating amounts to weight an amplitude and shift a phase of an associated one or more subcarriers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A multicarrier receiver comprising:
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a channel estimator to estimate a channel transfer matrix (H) for one or more subcarriers of a multicarrier communication channel;
beamformer matrix calculation circuitry to generate a quantized transmit beamformer matrix ({tilde over (V)}) for each of the subcarriers from an associated one of the channel transfer matrices (H); and
a plurality of receiver beamformers to combine input subcarrier signals in accordance with a receiver beamformer matrix (Ũ
H) for each subcarrier to separate constellation signals from each spatial channel,wherein the calculation circuitry calculates the receiver beamformer matrices (Ũ
H) from the channel transfer matrix (H) and the quantized transmit beamformer matrix ({tilde over (V)}) for an associated one of the subcarriers. - View Dependent Claims (16, 17, 18, 19, 20, 22, 23)
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21. The receiver of claim 21 wherein during the initial portions of the packet exchange, the transmitting station and the receiving station operate in a coarse quantization mode wherein the predetermined number of bits comprising the amplitude subfield ranges from zero bits to two bits and the predetermined number of bits comprising phase subfield ranges from one-bit to three bits, and
wherein during the subsequent portions the packet exchange, the transmitting station and the receiving station operate in a fine quantization mode wherein the predetermined number of bits comprises the amplitude subfield ranges from two bits to four bits and the predetermined number of bits comprising phase subfield ranges from three bits to five bits.
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24. A method for communicating signals over a multicarrier communication channel comprising:
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applying quantized transmit beamforming coefficients to a plurality of symbol-modulated subcarriers; and
performing an inverse fast Fourier transform to the symbol-modulated subcarriers after applying the quantized transmit beamforming coefficients, wherein the quantized transmit beamforming coefficients comprise predetermined numbers of bits for each subcarrier of a multicarrier communication channel indicating amounts to weight an amplitude and shift a phase of an associated subcarrier. - View Dependent Claims (25, 26)
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27. A method for communicating multicarrier communication signals over a multicarrier communication channel comprising:
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estimating a channel transfer matrix (H) for each subcarrier of the multicarrier communication channel;
generating a quantized transmit beamformer matrix (V) for each subcarrier from an associated one of the channel transfer matrices (H); and
combining input subcarrier signals in accordance with a receiver beamformer matrix (Ũ
H) for each subcarrier to separate constellation signals from each spatial channel,wherein the receiver beamformer matrix (Ũ
H) for a subcarrier is calculated from the channel transfer matrix (H) and the quantized transmit beamformer matrix ({tilde over (V)}) for the associated subcarrier, andwherein the input subcarrier signals were transmitted a transmitting station using the quantized transmit beamformer matrix ({tilde over (V)}). - View Dependent Claims (28, 29)
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30. A system comprising:
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one or more substantially omnidirectional antennas to receive signals through a multicarrier communication channel;
a channel estimator to estimate a channel transfer matrix (H) for one or more subcarriers of the multicarrier communication channel;
beamformer matrix calculation circuitry to generate a quantized transmit beamformer matrix ({tilde over (V)}) for each of the subcarriers from an associated one of the channel transfer matrices (H); and
a plurality of receiver beamformers to combine input subcarrier signals in accordance with a receiver beamformer matrix (Ũ
H) for each subcarrier to separate constellation signals from each spatial channel,wherein the calculation circuitry calculates the receiver beamformer matrices (Ũ
H) from the channel transfer matrix (H) and the quantized transmit beamformer matrix ({tilde over (V)}) for an associated one of the subcarriers. - View Dependent Claims (31, 32)
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33. A machine-readable medium that provides instructions, which when executed by one or more processors, cause the processors to perform operations comprising:
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estimating a channel transfer matrix (H) for each subcarrier of a multicarrier communication channel;
generating a quantized transmit beamformer matrix ({tilde over (V)}) for each subcarrier from an associated one of the channel transfer matrices (H); and
combining input subcarrier signals in accordance with a receiver beamformer matrix (Ũ
H) for each subcarrier to separate constellation signals from each spatial channel,wherein the receiver beamformer matrix (Ũ
H) for a subcarrier is calculated from the channel transfer matrix (H) and the quantized transmit beamformer matrix ({tilde over (V)}) for the associated subcarrier, andwherein the input subcarrier signals were transmitted a transmitting station using the quantized transmit beamformer matrix ({tilde over (V)}). - View Dependent Claims (34, 35)
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Specification