INTEGRATED CALIBRATION PROTOCOL FOR WIRELESS LANS

• US 20100260060A1
• Filed: 04/05/2010
• Published: 10/14/2010
• Est. Priority Date: 04/08/2009
• Status: Abandoned Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Vermani, Sameer, Sampath, Hemanth, Abraham, Santosh
• Application Number:
  US12/754,430
• Publication Number:
  US 20100260060A1
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 2025/03815 Transmission of a training request
• CPC Class Codes: H04L 25/0202 Channel estimation
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Certain aspects of the present disclosure provide a protocol for calibration of an access point in a wireless network.

Claims

1. A method for wireless communications by an access point (AP) for calibration of the AP, comprising:

transmitting a training request message (TRM) followed by a downlink sounding frame to a station to initiate a calibration procedure;

receiving uplink sounding packets and channel state information (CSI) feedback from a station;

estimating the uplink channel from the uplink sounding packets;

calculating calibration coefficients from the received uplink sounding packets and the CSI feedback message; and

applying the calibration coefficients to the channel estimated from the uplink sounding packets to correct the estimated channel.

2. The method of claim 1, further comprising:

calculating a calibrated precoding matrix based on the corrected channel estimate; and

performing downlink transmissions utilizing the calibrated precoding matrix.

3. The method of claim 2, wherein the downlink transmissions are sent via a Spatial Division Multiple Access (SDMA) transmission scheme.

4. The method of claim 1, wherein the calibration procedure is performed without interrupting a downlink data transmission.

5. A method for wireless communications by a station (STA), comprising:

receiving a training request message (TRM) followed by downlink sounding packets from an access point (AP);

calculating channel state information (CSI) from the downlink sounding packets;

transmitting uplink sounding packets and the channel state information (CSI) feedback to the AP for calibration; and

receiving downlink transmission from the AP that utilizes a calibrated precoding matrix.

6. The method of claim 5, wherein the CSI feedback is sent on a subset of antennas that are used for transmission of the uplink sounding packets.

7. An apparatus for wireless communications by an access point (AP) for calibration of the AP, comprising:

a transmitter configured to transmit a training request message (TRM) followed by a downlink sounding frame to a station to initiate a calibration procedure;

a receiver configured to receive uplink sounding packets and channel state information (CSI) feedback from a station;

an estimator configured to estimate the uplink channel from the uplink sounding packets; and

a calibrator configured to calculate calibration coefficients from the received uplink sounding packets and the CSI feedback message and apply the calibration coefficients to the channel estimated from the uplink sounding packets to correct the estimated channel.

8. The apparatus of claim 7, wherein:

the calibrator is configured to calculate a calibrated precoding matrix based on the corrected channel estimate; and

the transmitter is configured to perform downlink transmissions utilizing the calibrated precoding matrix.

9. The apparatus of claim 8, wherein the downlink transmissions are sent via a Spatial Division Multiple Access (SDMA) transmission scheme.

10. The apparatus of claim 8, wherein the calibrator is configured to perform a calibration procedure without interrupting a downlink data transmission.

14. The apparatus of claim 7, wherein:

the means for calculating is configured to calculate a calibrated precoding matrix based on the corrected channel estimate; and

the means for transmitting is configured to perform downlink transmissions utilizing the calibrated precoding matrix.

15. The apparatus of claim 8, wherein the downlink transmissions are sent via a Spatial Division Multiple Access (SDMA) transmission scheme.

16. The apparatus of claim 8, wherein the means for calculating is configured to perform a calibration procedure without interrupting a downlink data transmission.

11. An apparatus for wireless communications by a station (STA), comprising:

a receiver configured to receive a training request message (TRM) followed by downlink sounding packets from an access point (AP);

a calculator configured to calculate channel state information (CSI) from the downlink sounding packets; and

a transmitter configured to transmit uplink sounding packets and the channel state information (CSI) feedback to the AP for calibration;

wherein the receiver is configured to receive a downlink transmission from the AP utilizing a calibrated precoding matrix.

12. The apparatus of claim 11, wherein the CSI feedback is sent on a subset of antennas that are used for transmission of the uplink sounding packets.

18. The apparatus of claim 11, wherein the CSI feedback is sent on a subset of antennas that are used for transmission of the uplink sounding packets.

13. An apparatus for wireless communications by an access point (AP) for calibration of the AP, comprising:

means for transmitting a training request message (TRM) followed by a downlink sounding frame to a station to initiate a calibration procedure;

means for receiving uplink sounding packets and channel state information (CSI) feedback from a station;

means for estimating the uplink channel from the uplink sounding packets; and

means for calculating calibration coefficients from the received uplink sounding packets and the CSI feedback message and applying the calibration coefficients to the channel estimated from the uplink sounding packets to correct the estimated channel.

17. An apparatus for wireless communications by a station (STA), comprising:

means for receiving a training request message (TRM) followed by downlink sounding packets from an access point (AP);

means for calculating channel state information (CSI) from the downlink sounding packets;

means for transmitting uplink sounding packets and the channel state information (CSI) feedback to the AP for calibration; and

means for receiving a downlink transmission from the AP utilizing a calibrated precoding matrix.

19. A computer-program product for wireless communications by an access point (AP) for calibration of the AP, comprising a computer-readable medium having instructions stored thereon, the instructions being executable by one or more processors and the instructions comprising:

instructions for transmitting a training request message (TRM) followed by a downlink sounding frame to a station to initiate a calibration procedure;

instructions for receiving uplink sounding packets and channel state information (CSI) feedback from a station;

instructions for estimating the uplink channel from the uplink sounding packets;

instructions for calculating calibration coefficients from the received uplink sounding packets and the CSI feedback message; and

instructions for applying the calibration coefficients to the channel estimated from the uplink sounding packets to correct the estimated channel.

20. The method of claim 19, further comprising:

instructions for calculating a calibrated precoding matrix based on the corrected channel estimate; and

instructions for performing downlink transmissions utilizing the calibrated precoding matrix.

21. The computer-program product of claim 20, wherein the downlink transmissions are sent via a Spatial Division Multiple Access (SDMA) transmission scheme.

22. The computer-program product of claim 19, wherein the calibration procedure is performed without interrupting a downlink data transmission.

23. A computer-program product for wireless communications by a station (STA), comprising a computer-readable medium having instructions stored thereon, the instructions being executable by one or more processors and the instructions comprising:

instructions for receiving a training request message (TRM) followed by downlink sounding packets from an access point (AP);

instructions for calculating channel state information (CSI) from the downlink sounding packets;

instructions for transmitting uplink sounding packets and the channel state information (CSI) feedback to the AP for calibration; and

instructions for receiving downlink transmission from the AP that utilizes a calibrated precoding matrix.

24. The computer-program product of claim 23, wherein the CSI feedback is sent on a subset of antennas that are used for transmission of the uplink sounding packets.