TECHNIQUES FOR TRANSFORMATION CODEBOOK ANTENNA BEAMFORMING IN OFDM WIRELESS COMMUNICATION SYSTEM

• US 20110110451A1
• Filed: 10/26/2010
• Published: 05/12/2011
• Est. Priority Date: 11/06/2009
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: TSAI, Jiann-An, RAMAKRISHNA, Sudhir, PI, Zhouyue
• Granted Patent: US 8,625,693 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end

Abstract

Methods for a transmitter station and a receiver station to perform beamforming in a wireless communication system, and a transmitter station and a receiver station to perform the corresponding method, are provided. The method for the transmitter station to perform beamforming in the wireless communication system includes estimating and tracking a long-term averaged and normalized channel correlation matrix between the transmitter station and a receiver station, determining beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix, and communicating with the receiver station using the determined beamforming coefficients, wherein the receiver station also estimates and tracks the long term averaged and normalized channel correlation matrix, and determines beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix.

Claims

1. A method for a transmitter station to perform beamforming in a wireless communication system, the method comprising:

estimating and tracking a long-term averaged and normalized channel correlation matrix between the transmitter station and a receiver station;

determining beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix; and

communicating with the receiver station using the determined beamforming coefficients,

wherein the receiver station also estimates and tracks the long term averaged and normalized channel correlation matrix, and determines beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix.

2. The method of claim 1, wherein the estimating and the tracking of the long-term averaged and normalized channel correlation matrix by the transmitter station is simultaneously performed with the estimating and the tracking of the long-term averaged and normalized channel correlation matrix by the receiver station.

3. The method of claim 1, wherein the determining of the beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix, comprises:

applying the tracked long-term averaged and normalized channel correlation matrix to a base codebook to generate a transformed codebook; and

determining the beamforming coefficients based on the transformed codebook,

wherein the base codebook is a codebook that is predefined and known to both the transmitter station and the receiver station.

4. The method of claim 1, wherein the long-term averaged and normalized channel correlation matrix is tracked as a function of at least one of a forgetting factor, a random factor, a Channel Quality Indication (CQI) or a Signal to Interference plus Noise Ratio (SINR), reported transmit precoding indication from the receiver station that is based on a transformed codebook, a transmit precoding matrix at the transmitter station that corresponds to or is a function of the reported transmit precoding indication from the receiver station, and a complex random matrix.

5. The method of claim 1, wherein the long-term averaged and normalized channel correlation matrix is tracked using the equation:

{tilde over (R)}[t]=α

{tilde over (R)}[t−

1]+(1−

α

)w_j[t]w_j^H[t]γ

+β

v_random[t]v_random^H[t]

where {tilde over (R)}[t] denotes the long-term averaged and normalized channel correlation matrix {tilde over (R)} at time index t, α

denotes a forgetting factor that tracks the mobility of a mobile channel, w_j denotes a transmit precoding matrix at the transmitter station that corresponds to or is a function of reported transmit precoding indication from the receiver station, based on a transformed codebook, (*)^H denotes a Hermitian operation, γ

denotes a parameter corresponding to one of a Signal to Interference plus Noise Ratio (SINR) or a Channel Quality Indication (CQI) value, β

denotes a random factor that is used to avoid bias estimation of {tilde over (R)}, and v_random is a complex random matrix, which is simultaneously generated at both the transmitter station and the receiver station and is used to avoid a bias estimation of {tilde over (R)}.

6. The method of claim 1, wherein the long-term averaged and normalized channel correlation matrix is tracked as a function of at least one of a forgetting factor, a random factor, reported transmit precoding indication from the receiver station, a transmit precoding matrix at the transmitter station that corresponds to or is a function of the reported transmit precoding indication from the receiver station, based on a fixed or base codebook, a Channel Quality Indication (CQI) or a Signal to Interference plus Noise Ratio (SINR), and a complex random matrix.

7. The method of claim 1, wherein the long-term averaged and normalized channel correlation matrix is tracked using the equation:

{tilde over (R)}[t]=α

{tilde over (R)}[t−

1]+(1−

α

)p_i[t]p_i^H[t]γ

+β

v_random[t]v_random^H[t]

where {tilde over (R)}[t] denotes the long-term averaged and normalized channel correlation matrix {tilde over (R)} at time index t, α

denotes a forgetting factor that tracks the mobility of a mobile channel, p_i denotes a transmit precoding matrix at the transmitter station that corresponds to or is a function of reported transmit precoding indication from the receiver station, based on a fixed or base codebook P, (*)^H denotes a Hermitian operation, γ

denotes a parameter corresponding to one of a Signal to Interference plus Noise Ratio (SINR) or a Channel Quality Indication (CQI) value, β

denotes a random factor that is used to avoid bias estimation of {tilde over (R)}, and v_random is a complex random matrix, which is simultaneously generated at both the transmitter station and the receiver station and is used to avoid a bias estimation of {tilde over (R)}.

8. A method for a receiver station to perform beamforming in a wireless communication system, the method comprising:

estimating and tracking a long-term averaged and normalized channel correlation matrix between the receiver station and a transmitter station;

determining beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix; and

communicating with the transmitter station using the determined beamforming coefficients,

wherein the transmitter station also estimates and tracks the long term averaged and normalized channel correlation matrix, and determines beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix.

9. The method of claim 8, wherein the estimating and the tracking of the long-term averaged and normalized channel correlation matrix by the receiver station is simultaneously performed with the estimating and the tracking of the long-term averaged and normalized channel correlation matrix by the transmitter station.

10. The method of claim 8, wherein the determining of the beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix, comprises:

applying the tracked long-term averaged and normalized channel correlation matrix to a base codebook to generate a transformed codebook; and

determining the beamforming coefficients based on the transformed codebook,

wherein the base codebook is a codebook that is predefined and known to both the receiver station and the transmitter station.

11. The method of claim 8, wherein the long-term averaged and normalized channel correlation matrix is tracked as a function of at least one of a forgetting factor, a random factor, a Channel Quality Indication (CQI) or a Signal to Interference plus Noise Ratio (SINR), reported transmit precoding indication from the receiver station that is based on a transformed codebook, a transmit precoding matrix at the transmitter station which corresponds to or is a function of the reported transmit precoding indication from the receiver station, and a complex random matrix.

12. The method of claim 8, wherein the long-term averaged and normalized channel correlation matrix is tracked using the equation:

{tilde over (R)}[t]=α

{tilde over (R)}[t−

1]+(1−

α

)w_j[t]w_j^H[t]γ

+β

v_random[t]v_random^H[t]

where {tilde over (R)}[t] denotes the long-term averaged and normalized channel correlation matrix {tilde over (R)} at time index t, α

denotes a forgetting factor that tracks the mobility of a mobile channel, w_j denotes a transmit precoding matrix at the transmitter station that corresponds to or is a function of reported transmit precoding indication from the receiver station, based on a transformed codebook, (*)^H denotes a Hermitian operation, γ

denotes a parameter corresponding to one of a Signal to Interference plus Noise Ratio (SINR) or a Channel Quality Indication (CQI) value, β

denotes a random factor that is used to avoid bias estimation of {tilde over (R)}, and v_random is a complex random matrix, which is simultaneously generated at both the transmitter station and the receiver station and is used to avoid a bias estimation of {tilde over (R)}.

13. The method of claim 8, wherein the long-term averaged and normalized channel correlation matrix is tracked as a function of at least one of a forgetting factor, a random factor, reported transmit precoding indication from the receiver station, a transmit precoding matrix at the transmitter station that corresponds to or is a function of the reported transmit precoding indication from the receiver station, based on a fixed or base codebook, a Channel Quality Indication (CQI) or a Signal to Interference plus Noise Ratio (SINR), and a complex random matrix.

14. The method of claim 8, wherein the long-term averaged and normalized channel correlation matrix is tracked using the equation:

{tilde over (R)}[t]=α

{tilde over (R)}[t−

1]+(1−

α

)p_i[t]p_i^H[t]γ

+β

v_random[t]v_random^H[t]

where {tilde over (R)}[t] denotes the long-term averaged and normalized channel correlation matrix {tilde over (R)} at time index t, α

denotes a forgetting factor that tracks the mobility of a mobile channel, p_i denotes a transmit precoding matrix at the transmitter station that corresponds to or is a function of reported transmit precoding indication from the receiver station, based on a fixed or base codebook P, (*)^H denotes a Hermitian operation, γ

denotes a parameter corresponding to one of a Signal to Interference plus Noise Ratio (SINR) or a Channel Quality Indication (CQI) value, β

denotes a random factor that is used to avoid bias estimation of {tilde over (R)}, and v_random is a complex random matrix, which is simultaneously generated at both the transmitter station and the receiver station and is used to avoid a bias estimation of {tilde over (R)}.

15. A transmitter station for performing beamforming in a wireless communication system, the transmitter station comprising:

a receiver for receiving signals from a receiver station based on beamforming coefficients;

a transmitter for transmitting signals to the receiver station based on beamforming coefficients; and

a controller for estimating and tracking a long-term averaged and normalized channel correlation matrix between the transmitter station and the receiver station, for determining beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix, for controlling the receiver to receive signals from the receiver station using the determined beamforming coefficients, and for controlling the transmitter to transmit signals to the receiver station using the determined beamforming coefficients,

wherein the receiver station also estimates and tracks the long term averaged and normalized channel correlation matrix, and determines beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix.

16. The transmitter station of claim 15, wherein the estimating and the tracking of the long-term averaged and normalized channel correlation matrix by the transmitter station is simultaneously performed with the estimating and the tracking of the long-term averaged and normalized channel correlation matrix by the receiver station.

17. The transmitter station of claim 15, wherein the controller, when determining the beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix, applies the tracked long-term averaged and normalized channel correlation matrix to a base codebook to generate a transformed codebook, and determines the beamforming coefficients based on the transformed codebook,

wherein the base codebook is a codebook that is predefined and known to both the transmitter station and the receiver station.

18. The transmitter station of claim 15, wherein the controller tracks the long-term averaged and normalized channel correlation matrix as a function of at least one of a forgetting factor, a random factor, a Channel Quality Indication (CQI) or a Signal to Interference plus Noise Ratio (SINR), reported transmit precoding indication from the receiver station that is based on a transformed codebook, a transmit precoding matrix at the transmitter station which corresponds to or is a function of the reported transmit precoding indication from the receiver station, and a complex random matrix.

19. The transmitter station of claim 15, wherein the controller tracks the long-term averaged and normalized channel correlation matrix using the equation:

{tilde over (R)}[t]=α

{tilde over (R)}[t−

1]+(1−

α

)w_j[t]w_j^H[t]γ

+β

v_random[t]v_random^H[t]

where {tilde over (R)}[t] denotes the long-term averaged and normalized channel correlation matrix {tilde over (R)} at time index t, α

denotes a forgetting factor that tracks the mobility of a mobile channel, w_j denotes a transmitter precoding matrix at the transmitter station that corresponds to or is a function of reported transmit precoding indication from the receiver station, based on a transformed codebook, (*)^H denotes a Hermitian operation, γ

denotes a parameter corresponding to one of a Signal to Interference plus Noise Ratio (SINR) or a Channel Quality Indication (CQI) value, β

denotes a random factor that is used to avoid bias estimation of {tilde over (R)}, and v_random is a complex random matrix, which is simultaneously generated at both the transmitter station and the receiver station and is used to avoid a bias estimation of {tilde over (R)}.

20. The transmitter station of claim 15, wherein the controller tracks the long-term averaged and normalized channel correlation matrix as a function of at least one of a forgetting factor, a random factor, reported transmit precoding indication from the receiver station, a transmit precoding matrix at the transmitter station that corresponds to or is a function of the reported transmit precoding indication from the receiver station, based on a fixed or base codebook, a Channel Quality Indication (CQI) or a Signal to Interference plus Noise Ratio (SINR), and a complex random matrix.

21. The transmitter station of claim 15, wherein the controller tracks the long-term averaged and normalized channel correlation matrix using the equation:

{tilde over (R)}[t]=α

{tilde over (R)}[t−

1]+(1−

α

)p_i[t]p_i^H[t]γ

+β

v_random[t]v_random[t]

where {tilde over (R)}[t] denotes the long-term averaged and normalized channel correlation matrix {tilde over (R)} at time index t, α

denotes a forgetting factor that tracks the mobility of a mobile channel, p_i denotes a transmit precoding matrix at the transmitter station that corresponds to or is a function of reported transmit precoding indication from the receiver station, based on a fixed or base codebook P, (*)^H denotes a Hermitian operation, γ

denotes a parameter corresponding to one of a Signal to Interference plus Noise Ratio (SINR) or a Channel Quality Indication (CQI) value, β

denotes a random factor that is used to avoid bias estimation of {tilde over (R)}, and v_random is a complex random matrix, which is simultaneously generated at both the transmitter station and the receiver station and is used to avoid a bias estimation of {tilde over (R)}.

22. A receiver station for performing beamforming in a wireless communication system, the receiver station comprising:

a receiver for receiving signals from a transmitter station based on beamforming coefficients;

a transmitter for transmitting signals to the transmitter station based on beamforming coefficients; and

a controller for estimating and tracking a long-term averaged and normalized channel correlation matrix between the receiver station and the transmitter station, for determining beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix, for controlling the receiver to receive signals from the transmitter station using the determined beamforming coefficients, and for controlling the transmitter to transmit signals to the transmitter station using the determined beamforming coefficients,

wherein the transmitter station also estimates and tracks the long term averaged and normalized channel correlation matrix, and determines beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix.

23. The receiver station of claim 22, wherein the estimating and the tracking of the long-term averaged and normalized channel correlation matrix by the receiver station is simultaneously performed with the estimating and the tracking of the long-term averaged and normalized channel correlation matrix by the transmitter station.

24. The receiver station of claim 22, wherein the controller, when determining the beamforming coefficients based on the tracked long-term averaged and normalized channel correlation matrix, applies the tracked long-term averaged and normalized channel correlation matrix to a base codebook to generate a transformed codebook, and determines the beamforming coefficients based on the transformed codebook,

wherein the base codebook is a codebook that is predefined and known to both the receiver station and the transmitter station.

25. The receiver station of claim 22, wherein the controller tracks the long-term averaged and normalized channel correlation matrix as a function of at least one of a forgetting factor, a random factor, a Channel Quality Indication (CQI) or a Signal to Interference plus Noise Ratio (SINR), reported transmit precoding indication from the receiver station that is based on a transformed codebook, a transmit precoding matrix at the transmitter that corresponds to or is a function of the reported transmit precoding indication from the receiver station, and a complex random matrix.

26. The receiver station of claim 22, wherein the controller tracks the long-term averaged and normalized channel correlation matrix using the equation:

{tilde over (R)}[t]=α

{tilde over (R)}[t−

1]+(1−

α

)w_j[t]w_j^H[t]γ

+β

v_random[t]v_random^H[t]

where {tilde over (R)}[t] denotes the long-term averaged and normalized channel correlation matrix {tilde over (R)} at time index t, α

denotes a forgetting factor that tracks the mobility of a mobile channel, w_j denotes a transmit precoding matrix at the transmitter station that corresponds to or is a function of reported transmit precoding indication from the receiver station, based on a transformed codebook, (*)^H denotes a Hermitian operation, γ

denotes a parameter corresponding to one of a Signal to Interference plus Noise Ratio (SINR) or a Channel Quality Indication (CQI) value, β

denotes a random factor that is used to avoid bias estimation of {tilde over (R)}, and v_random is a complex random matrix, which is simultaneously generated at both the transmitter station and the receiver station and is used to avoid a bias estimation of {tilde over (R)}.

27. The receiver station of claim 22, wherein the controller tracks the long-term averaged and normalized channel correlation matrix as a function of at least one of a forgetting factor, a random factor, reported transmit precoding indication from the receiver station, a transmit precoding matrix at the transmitter station that corresponds to or is a function of the reported transmit precoding indication from the receiver station, based on a fixed or base codebook, a Channel Quality Indication (CQI) or a Signal to Interference plus Noise Ratio (SINR), and a complex random matrix.

28. The receiver station of claim 22, wherein the controller tracks the long-term averaged and normalized channel correlation matrix using the equation:

{tilde over (R)}[t]=α

{tilde over (R)}[t−

1]+(1−

α

)p_i[t]p_i^H[t]γ

+β

v_random[t]v_random^H[t]

where {tilde over (R)}[t] denotes the long-term averaged and normalized channel correlation matrix {tilde over (R)} at time index t, α

denotes a forgetting factor that tracks the mobility of a mobile channel, p_i denotes a transmit precoding matrix at the transmitter station that corresponds to or is a function of reported transmit precoding indication from the receiver station, based on a fixed or base codebook P, (*)^H denotes a Hermitian operation, γ

denotes a parameter corresponding to one of a Signal to Interference plus Noise Ratio (SINR) or a Channel Quality Indication (CQI) value, β

denotes a random factor that is used to avoid bias estimation of {tilde over (R)}, and v_random is a complex random matrix, which is simultaneously generated at both the transmitter station and the receiver station and is used to avoid a bias estimation of {tilde over (R)}.