Closed-loop transmission feedback in wireless communication systems
First Claim
Patent Images
1. A method in an orthogonal frequency division multiplexing (OFDM) wireless communication terminal, the method comprising:
- computing a transmit spatial covariance matrix corresponding to a channel estimated on a first set of two or more OFDM subcarriers corresponding to a received waveform;
obtaining a set of analog coefficients by transforming the transmit spatial covariance matrix;
modulating the set of analog coefficients onto a first portion of a second set of two or more OFDM subcarriers corresponding to a transmitted waveform, where each analog coefficient is mapped to a single OFDM subcarrier; and
modulating a pilot symbol onto a second portion of the second set of OFDM subcarriers, where the pilot symbol is from a finite constellation of complex symbols.
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Abstract
An orthogonal frequency division multiplexing wireless communication terminal, that communicates with a base unit, obtains a set of analog coefficients by transforming a transmit spatial covariance matrix, modulates the set of analog coefficients onto multiple channels to form a feedback waveform, and transmits the feedback waveform to the base unit.
24 Citations
22 Claims
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1. A method in an orthogonal frequency division multiplexing (OFDM) wireless communication terminal, the method comprising:
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computing a transmit spatial covariance matrix corresponding to a channel estimated on a first set of two or more OFDM subcarriers corresponding to a received waveform; obtaining a set of analog coefficients by transforming the transmit spatial covariance matrix; modulating the set of analog coefficients onto a first portion of a second set of two or more OFDM subcarriers corresponding to a transmitted waveform, where each analog coefficient is mapped to a single OFDM subcarrier; and modulating a pilot symbol onto a second portion of the second set of OFDM subcarriers, where the pilot symbol is from a finite constellation of complex symbols. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A orthogonal frequency division multiplexing (OFDM) wireless communication base unit comprising:
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a processor the processor is configured to obtain analog coefficients from a first portion of a second set of two or more OFDM subcarriers based on pilot symbols modulated on a second portion of the second set of two or more OFDM subcarriers, wherein the second set of two or more OFDM subcarriers correspond to a waveform received by the base unit, the analog coefficients obtained by transforming a transmit spatial covariance matrix, the transmit spatial covariance matrix based on a first set of two or more OFDM subcarriers corresponding to a waveform transmitted from the base unit, and the processor is configured to determine transmission parameters corresponding to the first set of two or more OFDM subcarrier based on the obtained analog coefficients. - View Dependent Claims (15, 16, 17, 18, 19)
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20. An orthogonal frequency division multiplexing wireless communication terminal comprising:
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the terminal configured to compute a transmit spatial covariance matrix corresponding to a channel estimated on a first set of two or more orthogonal frequency division multiplexing (OFDM) subcarriers corresponding to a received waveform, the terminal configured to obtain a set of analog coefficients by transforming the transmit spatial covariance matrix, the terminal configured to modulate the set of analog coefficients onto a first portion of a second set of two or more OFDM subcarriers corresponding to a transmitted waveform, where each analog coefficient is mapped to a single OFDM subcarrier, and the terminal configured to modulate a pilot symbol onto a second portion of the second set of OFDM subcarriers. - View Dependent Claims (21, 22)
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Specification