IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0008755
(2011-01-18)
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등록번호 |
US-8547865
(2013-10-01)
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발명자
/ 주소 |
- Meylan, Arnaud
- Abraham, Santosh Paul
- Nanda, Sanjiv
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출원인 / 주소 |
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
0 인용 특허 :
15 |
초록
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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 pi
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.
대표청구항
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1. An apparatus comprising: a channel processor to receive a first unsteered pilot via a first communication link and to derive a channel estimate for the first communication link based on the first unsteered pilot; anda controller to receive feedback information indicative of channel quality of a s
1. An apparatus comprising: a channel processor to receive a first unsteered pilot via a first communication link and to derive a channel estimate for the first communication link based on the first unsteered pilot; anda 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. 2. The apparatus of claim 1, wherein the controller sends a request for pilot and feedback information, and wherein the first unsteered pilot and the feedback information are sent in response to the request. 3. The apparatus of claim 1, further comprising: a pilot processor to generate a second unsteered pilot for transmission via the second communication link, and wherein the feedback information is derived based on the second unsteered pilot. 4. The apparatus of claim 1, wherein the channel processor estimates channel quality of the first communication link based on the first unsteered pilot, and 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. 5. The apparatus of claim 4, wherein the channel processor obtains a channel response matrix and an SNR estimate for the first communication link based on the first unsteered pilot and decomposes the channel response matrix to obtain channel gains for the eigenmodes, and wherein the controller estimates the SNRs of the eigenmodes based on the channel gains for the eigenmodes, the SNR estimate for the first communication link, and the feedback information. 6. The apparatus of claim 4, wherein the controller selects a rate for each eigenmode based on an SNR of the eigenmode. 7. The apparatus of claim 4, wherein the controller selects a rate combination for the eigenmodes based on the SNRs of the eigenmodes. 8. The apparatus of claim 1, wherein the feedback information comprises a signal-to-noise-and-interference ratio (SNR) estimate for the second communication link. 9. The apparatus of claim 1, wherein the feedback information comprises at least one rate or an overall throughput for the second communication link. 10. The apparatus of claim 1, wherein the feedback information comprises acknowledgments or negative acknowledgments for data packets. 11. The apparatus of claim 1, wherein the first unsteered pilot and the feedback information are received from a single transmission sent via the first communication link. 12. The apparatus of claim 1, wherein the feedback information is received for a prior data transmission sent via the second communication link. 13. The apparatus of claim 1, further comprising: a data processor to process data based on the rates selected for the eigenmodes; anda spatial processor to spatially process the data for transmission on the eigenmodes. 14. The apparatus of claim 1, wherein the first unsteered 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. 15. A method of performing rate selection, comprising: receiving a first unsteered pilot via a first communication link using at least one antenna;receiving feedback information indicative of channel quality of a second communication link; andselecting rates for eigenmodes of the second communication link based on the feedback information and the first unsteered pilot. 16. The method of claim 15, further comprising: sending a request for pilot and feedback information, and wherein the first unsteered pilot and the feedback information are sent in response to the request. 17. The method of claim 15, further comprising: transmitting a second unsteered pilot via the second communication link, and wherein the feedback information is derived based on the second unsteered pilot. 18. The method of claim 15, wherein the selecting the rates for the eigenmodes comprises estimating channel quality of the first communication link based on the first unsteered pilot,estimating 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, andselecting the rates for the eigenmodes based on the SNRs of the eigenmodes. 19. The method of claim 18, wherein the estimating the SNRs of the eigenmodes comprises obtaining a channel response matrix for the first communication link based on the first unsteered pilot,decomposing the channel response matrix to obtain channel gains for the eigenmodes, andderiving the SNRs of the eigenmodes based on the channel gains for the eigenmodes, the estimated channel quality of the first communication link, and the feedback information. 20. A hardware apparatus comprising: means for receiving a first unsteered pilot via a first communication link;means for receiving feedback information indicative of channel quality of a second communication link; andmeans for selecting rates for eigenmodes of the second communication link based on the feedback information and the first unsteered pilot. 21. The hardware apparatus of claim 20, further comprising: means for sending a request for pilot and feedback information, and wherein the first unsteered pilot and the feedback information are sent in response to the request. 22. The hardware apparatus of claim 20, further comprising: means for transmitting a second unsteered pilot via the second communication link, and wherein the feedback information is derived based on the second unsteered pilot. 23. The hardware apparatus of claim 20, wherein the means for selecting the rates for the eigenmodes comprises means for estimating channel quality of the first communication link based on the first unsteered pilot,means for estimating 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, andmeans for selecting the rates for the eigenmodes based on the SNRs of the eigenmodes. 24. The apparatus of claim 23, wherein the means for estimating the SNRs of the eigenmodes comprises means for obtaining a channel response matrix for the first communication link based on the first unsteered pilot,means for decomposing the channel response matrix to obtain channel gains for the eigenmodes, andmeans for deriving the SNRs of the eigenmodes based on the channel gains for the eigenmodes, the estimated channel quality of the first communication link, and the feedback information. 25. A method of performing rate selection in a multiple-input multiple-output (MIMO) communication system, comprising: 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; andselecting rates for eigenmodes of the downlink based on the feedback information and the second unsteered MIMO pilot. 26. The method of claim 25, wherein the selecting the rates for the eigenmodes of the downlink comprises estimating uplink channel quality based on the second unsteered MIMO pilot,obtaining a channel response matrix for the uplink based on the second unsteered MIMO pilot,decomposing the channel response matrix to obtain channel gains for the eigenmodes,estimating signal-to-noise-and-interference ratios (SNRs) of the eigenmodes based on the estimated uplink channel quality, the channel gains for the eigenmodes, and the feedback information, andselecting the rates for the eigenmodes based on the SNRs of the eigenmodes. 27. An apparatus comprising: a pilot processor to generate a first unsteered pilot for transmission via a first communication link;a controller to send feedback information indicative of channel quality of a second communication link; anda 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 unsteered pilot and the feedback information. 28. The apparatus of claim 27, wherein the controller receives a request for pilot and feedback information and sends the first unsteered pilot and the feedback information in response to the request. 29. The apparatus of claim 27, further comprising: a channel processor to receive a second unsteered pilot via the second communication link and to derive a signal-to-noise-and-interference ratio (SNR) estimate for the second communication link based on the second unsteered pilot, and wherein the controller generates the feedback information based on the SNR estimate. 30. The apparatus of claim 27, wherein the pilot processor generates the first unsteered pilot as an unsteered multiple-input multiple-output (MIMO) pilot suitable for transmission from a plurality of antennas. 31. A method of performing rate selection, comprising: transmitting a first unsteered pilot via a first communication link;sending feedback information indicative of channel quality of a second communication link; andreceiving a data transmission on eigenmodes of the second communication link, wherein the data transmission is sent at rates selected based on the first unsteered pilot and the feedback information. 32. The method of claim 31, further comprising: receiving a request for pilot and feedback information, and wherein the first unsteered pilot and the feedback information are sent in response to the request. 33. The method of claim 31, further comprising: receiving a second unsteered pilot via the second communication link;deriving a signal-to-noise-and-interference ratio (SNR) estimate for the second communication link based on the second unsteered pilot; andgenerating the feedback information based on the SNR estimate. 34. A hardware apparatus comprising: means for transmitting a first unsteered pilot via a first communication link;means for sending feedback information indicative of channel quality of a second communication link; andmeans 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 unsteered pilot and the feedback information. 35. The hardware apparatus of claim 34, further comprising: means for receiving a request for pilot and feedback information, and wherein the first unsteered pilot and the feedback information are sent in response to the request. 36. The hardware apparatus of claim 34, further comprising: means for receiving a second unsteered pilot via the second communication link;means for deriving a signal-to-noise-and-interference ratio (SNR) estimate for the second communication link based on the second unsteered pilot; andmeans for generating the feedback information based on the SNR estimate.
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