Method for computing a downlink beamforming weighting vector based on up link channel information
First Claim
1. A method comprising:
- receiving at a plurality of antennas of an antenna array of a base station an uplink transmission that is transmitted from a mobile station, wherein the uplink transmission is transmitted in an uplink channel that comprises a plurality of sub-channels, each of which comprises a plurality of subcarriers;
computing uplink channel coefficients for the uplink channel from the received uplink transmission at the base station;
computing for each antenna in the antenna array of the base station, one or more coefficients for a time-domain channel impulse response function from the uplink channel coefficients;
computing a frequency response of the uplink channel from the time-domain channel impulse response function for each antenna;
calculating a spatial signature of the uplink channel from the frequency response; and
computing a downlink beamforming weighting vector for use when making a downlink transmission via the antenna array of the base station on a downlink channel to the mobile station from the spatial signature of the uplink channel, wherein the downlink channel comprises a plurality of downlink sub-channels that share few or no frequency sub-carriers with the plurality of uplink sub-channels.
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Accused Products
Abstract
Described herein is a method for obtaining a downlink beamforming weighting vector in a wireless communications system based on channel information about an uplink channel. The method comprises obtaining the channel information about the uplink channel by a means selected from the group comprising of training signals, pilot signals, and data signals, wherein the uplink channel comprises a set of uplink sub-channels, calculating a spatial signature of the uplink channel with the channel information, and computing a downlink beamforming weighting vector of a downlink channel with the spatial signature of the uplink channel, wherein the downlink channel comprises a set of downlink sub-channels that share few or no sub-carriers with the set of uplink sub-channels.
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Citations
14 Claims
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1. A method comprising:
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receiving at a plurality of antennas of an antenna array of a base station an uplink transmission that is transmitted from a mobile station, wherein the uplink transmission is transmitted in an uplink channel that comprises a plurality of sub-channels, each of which comprises a plurality of subcarriers; computing uplink channel coefficients for the uplink channel from the received uplink transmission at the base station; computing for each antenna in the antenna array of the base station, one or more coefficients for a time-domain channel impulse response function from the uplink channel coefficients; computing a frequency response of the uplink channel from the time-domain channel impulse response function for each antenna; calculating a spatial signature of the uplink channel from the frequency response; and computing a downlink beamforming weighting vector for use when making a downlink transmission via the antenna array of the base station on a downlink channel to the mobile station from the spatial signature of the uplink channel, wherein the downlink channel comprises a plurality of downlink sub-channels that share few or no frequency sub-carriers with the plurality of uplink sub-channels. - View Dependent Claims (2, 3, 4, 5, 6, 12, 13)
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7. A method comprising:
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receiving at a plurality of antennas of an antenna array of a base station an uplink transmission that is transmitted from a mobile station, wherein the uplink transmission is transmitted in an uplink channel that comprises a plurality of sub-channels, each of which is composed of a plurality of subcarriers; computing uplink channel coefficients for the uplink channel from the received uplink transmission at the base station; calculating a spatial signature of the uplink channel from the uplink channel coefficients; and computing a downlink beamforming weighting vector for use when making a downlink transmission via the antenna array of the base station in a downlink channel to the mobile station from the spatial signature of the uplink channel, wherein the downlink channel comprises a set of downlink sub-channels of frequency subcarriers that fall within neighborhoods of one or more uplink sub-channels of frequency subcarriers. - View Dependent Claims (8, 9, 10, 11, 14)
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Specification