Transmit signal preprocessing based on transmit antennae correlations for muliple antennae systems

• US 20030043929A1
• Filed: 09/06/2001
• Published: 03/06/2003
• Est. Priority Date: 09/06/2001
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Sampath, Hemanth
• Granted Patent: US 7,149,254 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0028 Variable division signaling therefor H04L5/0092

Abstract

The present invention provides a method and system for preprocessing transmit signals in spatial multiplexing and diversity systems that include multiple transmit antennae. The method includes generating a representative correlation matrix based upon estimates of a correlation between each pair of the plurality of antennae. An equivalent eigenvalue decomposition of the representative correlation matrix is determined. A preprocessing matrix based upon the equivalent eigenvalue decomposition is generated. Finally, a preprocessor preprocesses the transmit signals by multiplying blocks of data of the transmit signals with the preprocessing matrix. The representative correlation matrix can be an exact estimate of the correlation between each pair of the multiple antennae, or the representative correlation matrix can be an approximate estimate of the correlation between each pair of the multiple antennae.

Claims

1. A method of preprocessing transmit signals of a transmitter having a plurality of antennae, the method comprising:

generating a representative correlation matrix based upon estimates of a correlation between each pair of the plurality of antennae;

determining an equivalent eigenvalue decomposition of the representative correlation matrix;

generating a preprocessing matrix based upon the equivalent eigenvalue decomposition; and

a preprocessor preprocessing the transmit signals by multiplying blocks of data of the transmit signals with the preprocessing matrix.

2. The method of preprocessing signals of claim 1, wherein the representative correlation matrix is base upon a mean estimate of a channel matrix that represents a transmission channel between the plurality of antennae and a receiver.

3. The method of preprocessing signals of claim 1, wherein the representative correlation matrix is base upon a covariance estimate of a channel matrix that represents a transmission channel between the plurality of antennae and a receiver.

4. The method of preprocessing signals of claim 1, further comprising:

generating an eigenvector from the representative correlation matrix; and

wherein

generating a preprocessing matrix comprises multiplying the eigenvector with a scaler.

5. The method of preprocessing signals of claim 1, further comprising:

selecting a number B largest eigenvectors of the representative correlation matrix, where B is a number of data streams received by the preprocessor;

generating an orthogonal matrix from the B largest eigenvectors; and

wherein

generating a preprocessing matrix comprises multiplying the orthogonal matrix with a scaling matrix.

6. The method of preprocessing signals of claim 5, wherein the data streams received by the preprocessor are generated by a space/time processor.

7. The method of preprocessing signals of claim 6, wherein the space/time processor provides spatial multiplexing.

8. The method of preprocessing signals of claim 1, further comprising:

selecting a number B largest correlation eigenvectors of the representative correlation matrix, where B is a number of data streams received by the preprocessor;

generating a first orthogonal matrix from the B largest eigenvectors;

generating a minimum distance error matrix from a space/time processor that generates the data streams;

selecting a number B largest minimum distance eigenvectors of the minimum distance error matrix;

generating a second orthogonal matrix from the B largest minimum distance eigenvectors; and

wherein

generating a preprocessing matrix comprises multiplying the first orthogonal matrix with a scaler matrix and the second orthogonal matrix.

9. The method of preprocessing signals of claim 8, wherein the data streams received by the preprocessor are generated by a space/time processor.

10. The method of preprocessing signals of claim 9, wherein the space/time processor that generates the data streams provides transmission diversity.

11. The method of preprocessing signals of claim 1, wherein the representative correlation matrix is an exact estimate of the correlation between each pair of the multiple antennae.

12. The method of preprocessing signals of claim 1, wherein the representative correlation matrix is generated by a receiver that receives the preprocessed transmit signals.

13. The method of preprocessing signals of claim 1, wherein the representative correlation matrix is generated by a transmitter that transmits the preprocessed transmit signals.

14. The method of preprocessing signals of claim 1, wherein the preprocessed transmit signals are modulated with a multi-carrier modulator.

15. The method of preprocessing signals of claim 14, wherein the multi-carrier modulator comprises an orthogonal frequency division multiplexer.

16. The method of preprocessing signals of claim 14, further comprising a plurality of preprocessors, wherein a preprocessor corresponds with at least one of each of a plurality carrier signals of the multi-carrier modulator.

17. The method of preprocessing signals of claim 16, wherein each preprocessing matrix of each of the plurality of preprocessors is based upon a correlation matrix between each pair of the plurality of antennae at a frequency of the corresponding carrier signal.

18. The method of preprocessing signals of claim 1, wherein the transmit signals are formatted according to at least one of the following multiple access schemes:

time division multiple access (TDMA), frequency division multiple access (FDMA), code division multiple access (CDMA), orthogonal frequency division multiple access (OFDMA) and wavelet division multiple access.

19. A system for preprocessing signals to be transmitted from a transmitter having multiple antennae, to a receiver for receiving the preprocessed signals, comprising:

means for generating a representative correlation matrix based upon estimates of a correlation between signal transmitted from each pair of the multiple antennae;

means for determining an equivalent eigenvalue decomposition of the representative correlation matrix;

means for generating a preprocessing matrix based upon the equivalent eigenvalue decomposition; and

a preprocessor for preprocessing the transmit signals by multiplying blocks of data of the transmit signals with the preprocessing matrix.

20. The system for preprocessing signals of claim 19, wherein the receiver comprises a post-processor that comprises at least one of a maximum likelihood receiver, a beam former, an minimum mean square error receiver, a zero forcing receiver.

21. The system for preprocessing signals of claim 19, further comprising multiple preprocessors in which a preprocessor is selected based upon the preprocessing matrix.

22. A system for preprocessing signals to be transmitted from a plurality of transmitters, each transmitter having at least one transmit antenna, to a receiver, comprising:

means for generating a representative correlation matrix based upon estimates of a correlation between signal transmitted from each pair of transmitter antennae;

means for determining an equivalent eigenvalue decomposition of the representative correlation matrix;

means for generating a preprocessing matrix based upon the equivalent eigenvalue decomposition; and

a preprocessor within each transmitter for preprocessing the transmit signals by multiplying blocks of data of the transmit signals with the preprocessing matrix.

23. A method of preprocessing transmit signals of a transmitter having a plurality of antennae, the method comprising:

generating a representative correlation matrix based upon estimates of a correlation between each pair of the plurality of antennae;

generating a preprocessing matrix based upon the representative correlation matrix; and

a preprocessor preprocessing the transmit signals by multiplying blocks of data of the transmit signals with the preprocessing matrix.

24. The system for preprocessing signals of claim 23, further comprising:

determining an equivalent eigenvalue decomposition of the representative correlation matrix; and

generating the preprocessing matrix based upon the equivalent eigenvalue decomposition.

25. The method of preprocessing signals of claim 24, further comprising:

generating an eigenvector from the representative correlation matrix; and

wherein generating a preprocessing matrix comprises multiplying the eigenvector with a scaler.