Source: https://patents.google.com/patent/US9077518B2/en
Timestamp: 2019-12-07 01:43:52
Document Index: 602851999

Matched Legal Cases: ['Application No. 200580030257', 'Application No. 94129087', 'Application No. 200580030257', 'Application No. 200580030257', 'Application No. 200580030257', 'Application No. 200580030257', 'Application No. 200580030257', 'Application No. 112005002157', 'Application No. 94129087', 'Application No. 0700386', 'Application No. 0700386']

US9077518B2 - Downlink transmit beamforming - Google Patents
US9077518B2
US9077518B2 US14/175,381 US201414175381A US9077518B2 US 9077518 B2 US9077518 B2 US 9077518B2 US 201414175381 A US201414175381 A US 201414175381A US 9077518 B2 US9077518 B2 US 9077518B2
US14/175,381
US20140153662A1 (en
2012-02-27 Priority to US13/405,535 priority patent/US8660105B2/en
2014-02-07 Application filed by Intel Corp filed Critical Intel Corp
2014-02-07 Priority to US14/175,381 priority patent/US9077518B2/en
2014-06-05 Publication of US20140153662A1 publication Critical patent/US20140153662A1/en
2015-07-07 Publication of US9077518B2 publication Critical patent/US9077518B2/en
The present application is a continuation of U.S. application Ser. No. 13/405,535 filed Feb. 27, 2012, pending, which is a continuation of U.S. application Ser. No. 12/752,517 filed Apr. 1, 2010, now U.S. Pat. No. 8,125,923, which is continuation of U.S. application Ser. No. 11/027,300 filed Dec. 30, 2004, now U.S. Pat. No. 7,719,993. Said application Ser. Nos. 13/405,535, 12/752,517 and 11/027,300 are hereby incorporated by reference herein in their entireties.
where xS1 and xS2 are the signals sent to the AP; yA1, yA2, and yA3 are the received signal at the output of the AP's receive chains; aS1 and aA2 are the transmit chain gains of the two station's transmit chains; βA1, βA2 and βA3 are the receive chain gains of the AP's receive chains. Hu is referred to herein as the “aggregate uplink channel.”
where A+is the transpose conjugate of A.
Therefore the received data stream [ys1,ys2] does not contain cross interference.
where Mr is the number of receive antennas and also the number of data streams; li is the power loading factor of the i-th data stream; di is the data symbol in the i-th data stream; ri is the received signal on the i-th receive antenna; ni is the additive Gaussian white noise on the i-th receive chain; l1, . . . , lM r normalize the total transmit power and load different powers to different beamformed channels. For the equal power loading case, the performance of the system is substantially equal to that of an open loop Mr by Mt and better than that of Mr by Mr, where Mt>Mr. For example, for a 4×2 system, the performance of the system with equal power loading is equal to that of 2×4 open loop and better than that of 2×2 open loop.
W 0 = arg ⁢ ⁢ ⁢ min w ⁢ E ⁢ {  HWd ∑ i ⁢ ⁢ ∑ j ⁢ ⁢  w ij  2 + n - d  2 } . ( 10 )
1. Send a training symbol x0 for the n-th OFDM sub-carrier using transmit chain 1. 2. Measure the output of receive chain 2. The measured output is given by t12 = αA1C12βA2x0, where C12 is the response from the input of antenna 1 to the output of antenna 2. 3. Send a training symbol x0 for the n-th sub-carrier using transmit chain 2. 4. Measure the output of receive chain 1. The measured output is given by t21 = αA2C21βA1x0, where C21 is the response from the input of antenna 2 to the output of antenna 1. 5. Adjust αA1, αA2, βA1 and βA2 to set t12 = t21. The simplest way is to vary only the βA2. The adjustments of the chain gains can be implemented in the digital domain at or after analog-to-digital converters. After the adjustment or compensation, t12 = t21 gives αA1C12βA2x0 = αA2C21βA1x0 (12) 6. Since C12 = C21 due to reciprocity, (12) can be simplified as α A ⁢ ⁢ 1 β A ⁢ ⁢ 1 = α A ⁢ ⁢ 2 β A ⁢ ⁢ 2 (13) 7. FOR i = 3, . . . , M DO 1) Send a training symbol x0 for the n-th sub-carrier using transmit chain 1. 2) Measure the output of receive chain i. The measured output is given by t1i = αA1C1iβAix0, where C1i is the response from the input of antenna 1 to the output of antenna i. 3) Send a training symbol x0 for the n-th sub-carrier using transmit chain i. 4) Measure the output of receive chain 1. The measured output is given by ti1 = αAiCi1βA1x0, where Ci1 is the response from the input of antenna i to the output of antenna 1. 5) Adjust αAi and βAi to set t1i = ti1. The simplest way is to vary only the βAi. The adjustments of the chain gains can be implemented in the digital domain at or after analog-to-digital converters. After the adjustment or compensation, t1i = ti1 gives αA1C1iβAix0 = αAiCi1βA1x0 (14) 6) Since C1i = Ci1 due to reciprocity, (14) can be simplified as α A ⁢ ⁢ 1 β A ⁢ ⁢ 1 = α A ⁢ ⁢ i β A ⁢ ⁢ i (15) 8. END
calibrating a plurality of transmit/receive chains in a wireless network access point device, wherein calibrating comprises adjusting gain values to make transmitter gain to receiver gain ratios substantially equal;
receiving a packet in an uplink from a station having a first antenna and a second antenna, wherein uplink channel information is determined from the packets received from the station;
determining a downlink beamforming matrix using the uplink channel information reciprocity to form separate beams for the downlink for the first antenna and the second antenna of the station; and
transmitting two data streams to the station.
2. A method as claimed in claim 1, wherein said determining the downlink beamforming matrix comprises using a pseudo-inversion of an uplink channel matrix to determine the downlink beamforming matrix from the uplink channel state information.
3. A method as claimed in claim 1, wherein said transmitting two data streams to the station comprises transmitting a first data stream to the first antenna of the station, and transmitting the second data stream to the second antenna of the station.
4. A method as claimed in claim 1, wherein interference between the two data streams is mitigated by using zero-forcing.
5. A method as claimed in claim 1, wherein interference between the two data streams is mitigated by using minimum mean squared error (MMSE).
6. A method as claimed in claim 1, wherein said receiving comprises receiving open loop packets from the station.
a physical layer coupled to the two or more antennas; and
a media access control layer coupled to the physical layer, wherein the media access control layer is configured to:
calibrate a plurality of transmit/receive chains in a wireless network access point device, wherein calibrating comprises adjusting gain values to make transmitter gain to receiver gain ratios substantially equal;
receive a packet in an uplink from a station having a first antenna and a second antenna, wherein uplink channel information is determined from the packets received from the station;
determine a downlink beamforming matrix using the uplink channel information reciprocity to form separate beams for the downlink for the first antenna and the second antenna of the station; and
transmit two data streams to the station.
8. An access point as claimed in claim 7, wherein the media access control layer is further configured to use a pseudo-inversion of an uplink channel matrix to determine the downlink beamforming matrix from the uplink channel state information.
9. An access point as claimed in claim 7 wherein the media access control layer is further configured to transmit a first data stream to the first antenna of the station, and transmit the second data stream to the second antenna of the station.
10. An access point as claimed in claim 7, wherein the media access control layer is further configured to mitigate interference between the two data streams by using zero-forcing.
11. An access point as claimed in claim 7, wherein the media access control layer is further configured to mitigate interference between the two data streams by using minimum mean squared error (MMSE).
12. An access point as claimed in claim 7, wherein the packets received from the station comprise open loop packets.
13. An article of manufacture comprising a non-transitory medium having instructions stored thereon that, if executed, result in:
14. An article of manufacture as claimed in claim 13, wherein the instructions, if executed, further result in using a pseudo-inversion of an uplink channel matrix to determine the downlink beamforming matrix from the uplink channel state information.
15. An article of manufacture as claimed in claim 13, wherein the instructions, if executed, further result in transmitting a first data stream to the first antenna of the station, and transmitting the second data stream to the second antenna of the station.
16. An article of manufacture as claimed in claim 13, wherein the instructions, if executed, further result in mitigating interference between the two data streams by using zero-forcing.
17. An article of manufacture as claimed in claim 13, wherein the instructions, if executed, further result in mitigating interference between the two data streams by using minimum mean squared error (MMSE).
18. An article of manufacture as claimed in claim 13, wherein the packets received from the station comprise open loop packets.
US14/175,381 2004-12-30 2014-02-07 Downlink transmit beamforming Active US9077518B2 (en)
US14/731,174 Continuation US20160020834A1 (en) 2004-12-30 2015-06-04 Downlink transmit beamforming
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International Search Report and Written Opinion received for PCT Patent Application No. PCT/US2005/031681, mailed on Feb. 6, 2006, 10 pages.
Notice of Allowance received for Chinese Patent Application No. 200580030257.0, mailed on Jul. 4, 2012, 4 pages including 2 pages of English Translation.
Notice of Allowance received for Taiwanese Patent Application No. 94129087, mailed on Sep. 30, 2008, 5 pages including 1 page of English Translation.
Office Action received for Chinese Patent Application No. 200580030257.0, mailed on Aug. 3, 2010, 10 pages of Chinese Office Action and 17 pages of English Translation.
Office Action received for Chinese Patent Application No. 200580030257.0, mailed on Aug. 3, 2011, 8 pages of English Translation only.
Office Action received for Chinese Patent Application No. 200580030257.0, mailed on Jan. 31, 2012, 3 pages of Chinese Office Action and 4 pages of English Translation.
Office Action received for Chinese Patent Application No. 200580030257.0, mailed on May 8, 2009, 10 pages of Chinese Office Action and 18 pages of English Translation.
Office Action received for Chinese Patent Application No. 200580030257.0, mailed on Nov. 27, 2009, 10 pages of Chinese Office Action and 17 pages of English translation.
Office Action received for German Patent Application No. 112005002157.2, mailed on Jun. 30, 2009, 4 pages of German Office Action and 4 pages of English Translation.
Office Action received for Taiwanese Patent Application No. 94129087, mailed on Dec. 6, 2006, 1 page of English Translation.
Office Action received for United Kingdom Patent Application No. 0700386.6, mailed on Mar. 2, 2009, 1 page.
Office Action received for United Kingdom Patent Application No. 0700386.6, mailed on Sep. 19, 2008, 1 page.
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