Rate selection for eigensteering in a MIMO communication system
First Claim
1. An apparatus comprising:
- a channel processor to receive a first pilot via a first communication link and to derive a channel estimate for the first communication link, wherein the channel processor estimates channel quality of the first communication link based on the first pilot; and
a controller to receive feedback information indicative of channel quality of a second communication link and to select rates for eigenmodes of the second communication link based on the feedback information and the channel estimate, wherein the controller estimates signal-to-noise-and-interference ratios (SNRs) of the eigenmodes based on the estimated channel quality of the first communication link and the feedback information and further selects the rates for the eigenmodes based on the SNRs of the eigenmodes.
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Abstract
Techniques for selecting rates for data transmission on eigenmodes of a MIMO channel are described. An access point transmits an unsteered MIMO pilot via the downlink. A user terminal estimates the downlink channel quality based on the downlink unsteered MIMO pilot and transmits an unsteered MIMO pilot and feedback information via the uplink. The feedback information is indicative of the downlink channel quality. The access point estimates the uplink channel quality and obtains a channel response matrix based on the uplink unsteered MIMO pilot, decomposes the channel response matrix to obtain eigenvectors and channel gains for the eigenmodes of the downlink, and selects rates for the eigenmodes based on the estimated uplink channel quality, the channel gains for the eigenmodes, and the feedback information. The access point processes data based on the selected rates and transmits steered data and a steered MIMO pilot on the eigenmodes with the eigenvectors.
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Citations
32 Claims
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1. An apparatus comprising:
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a channel processor to receive a first pilot via a first communication link and to derive a channel estimate for the first communication link, wherein the channel processor estimates channel quality of the first communication link based on the first pilot; and a controller to receive feedback information indicative of channel quality of a second communication link and to select rates for eigenmodes of the second communication link based on the feedback information and the channel estimate, wherein the controller estimates signal-to-noise-and-interference ratios (SNRs) of the eigenmodes based on the estimated channel quality of the first communication link and the feedback information and further selects the rates for the eigenmodes based on the SNRs of the eigenmodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An apparatus comprising:
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a channel processor to receive a first pilot via a first communication link and to derive a channel estimate for the first communication link; and a controller to receive feedback information indicative of channel quality of a second communication link and to select rates for eigenmodes of the second communication link based on the feedback information and the channel estimate, wherein the first pilot is an unsteered multiple-input multiple-output (MIMO) pilot sent from a first plurality of antennas and received via a second plurality of antennas.
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14. A method of performing rate selection by a device in a wireless communications system, comprising:
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receiving a first pilot via a first communication link and estimating channel quality of the first communication link based on the first pilot; receiving feedback information indicative of channel quality of a second communication link; estimating signal-to-noise-and-interference ratios (SNRs) of eigenmodes of the second communication link based on the estimated channel quality of the first communication link and the feedback information; and selecting rates for the eigenmodes of the second communication link based on the feedback information and the SNRs of the eigenmodes. - View Dependent Claims (15, 16, 17)
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18. An apparatus comprising:
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means for receiving a first pilot via a first communication link and estimating channel quality of the first communication link based on the first pilot; means for receiving feedback information indicative of channel quality of a second communication link; means for estimating signal-to-noise-and-interference ratios (SNRs) of eigenmodes of the second communication link based on the estimated channel quality of the first communication link and the feedback information; and means for selecting rates for the eigenmodes of the second communication link based on the feedback information and the SNRs of the eigenmodes. - View Dependent Claims (19, 20, 21)
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22. A method of performing rate selection in a multiple-input multiple-output (MIMO) communication system, comprising:
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transmitting a first unsteered MIMO pilot via a downlink; receiving a second unsteered MIMO pilot and feedback information via an uplink, wherein the feedback information is indicative of downlink channel quality estimated based on the first unsteered MIMO pilot; and selecting rates for eigenmodes of the downlink based on the feedback information and the second unsteered MIMO pilot. - View Dependent Claims (23)
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24. An apparatus comprising:
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a pilot processor to generate a first pilot for transmission via a first communication link; a controller to send feedback information indicative of channel quality of a second communication link; and a spatial processor to receive a data transmission on eigenmodes of the second communication link, wherein the data transmission is sent at rates selected based on the first pilot and the feedback information, wherein the pilot processor generates the first pilot as an unsteered multiple-input multiple-output (MIMO) pilot suitable for transmission from a plurality of antennas. - View Dependent Claims (25, 26)
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27. A method of performing rate selection, comprising:
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transmitting a first pilot via a first communication link; sending feedback information indicative of channel quality of a second communication link; and receiving a data transmission on eigenmodes of the second communication link, wherein the data transmission is sent at rates selected based on the first pilot and the feedback information, wherein the first pilot is generated as an unsteered multiple-input multiple-output (MIMO) pilot suitable for transmission from a plurality of antennas. - View Dependent Claims (28, 29)
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30. An apparatus comprising:
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means for transmitting a first pilot via a first communication link; means for sending feedback information indicative of channel quality of a second communication link; and means for receiving a data transmission on eigenmodes of the second communication link, wherein the data transmission is sent at rates selected based on the first pilot and the feedback information; wherein the means for transmitting generates the first pilot as an unsteered multiple-input multiple-output (MIMO) pilot suitable for transmission from a plurality of antennas. - View Dependent Claims (31, 32)
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Specification