Time-domain transmit and receive processing with channel eigen-mode decomposition for MIMO systems

• US 6,760,388 B2
• Filed: 12/07/2001
• Issued: 07/06/2004
• Est. Priority Date: 12/07/2001
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Walton, Jay Rod, Howard, Steven J., Ketchum, John W., Wallace, Mark
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): ODOM, CURTIS B
• Application Number:
  US10/017,308
• Publication Number:
  US 20030108117A1
• Time in Patent Office: 942 Days
• Field of Search: 375/260, 375/267, 375/347, 375/346, 375/295, 342/378, 455/562, 330/151
• US Class Current: 375/295
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0443 utilizing "waterfilling" technique
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0029 Reduction of the amount of signalling, e.g. retention of useful signalling or differential signalling power control H04W52/04
• CPC Class Codes: H04L 2025/0349 as a feedback filter
• CPC Class Codes: H04L 2025/03605 Block algorithms
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/03834 using pulse shaping
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

Techniques for processing a data transmission at the transmitter and receiver. In an aspect, a time-domain implementation is provided which uses frequency-domain singular value decomposition and “water-pouring” results to derive time-domain pulse-shaping and beam-steering solutions at the transmitter and receiver. The singular value decomposition is performed at the transmitter to determine eigen-modes (i.e., spatial subchannels) of the MIMO channel and to derive a first set of steering vectors used to “precondition” modulation symbols. The singular value decomposition is also performed at the receiver to derive a second set of steering vectors used to precondition the received signals such that orthogonal symbol streams are recovered at the receiver, which can simplify the receiver processing. Water-pouring analysis is used to more optimally allocate the total available transmit power to the eigen-modes, which then determines the data rate and the coding and modulation scheme to be used for each eigen-mode.

Claims

1. A method for transmitting data in a multiple-input multiple-output (MIMO) communication system, comprising:

coding data in accordance with one or more coding schemes to provide coded data for a plurality of transmission channels in a MIMO channel;

modulating the coded data in accordance with one or more modulation schemes to provide a plurality of streams of modulation symbols;

deriving a pulse-shaping matrix based in part on a first sequence of matrices of eigen-vectors and a second sequence of matrices of singular values corresponding to an estimated channel response matrix of the MIMO channel;

preconditioning the plurality of modulation symbol streams based on the pulse-shaping matrix to derive a plurality of preconditioned signals; and

transmitting the plurality of preconditioned signals over the MIMO channel.

2. The method of claim 1 wherein deriving the pulse-shaping matrix comprises:

determining the estimated channel response matrix for the MIMO channel; and

decomposing the estimated channel response matrix to obtain the first sequence of matrices of eigen-vectors and the second sequence of matrices of singular values.

3. The method of claim 2, wherein the estimated channel response matrix is given in the frequency domain and is decomposed in the frequency domain.

4. The method of claim 2, wherein the estimated channel response matrix is decomposed based on singular value decomposition.

5. The method of claim 2, wherein the estimated channel response matrix comprises a plurality of eigen-modes, and wherein eigen-modes associated with singular values below a particular threshold are not selected for use for data transmission.

9. The method of claim 1, wherein the pulse-shaping matrix comprises a plurality of sequences of time-domain values, and wherein the preconditioning is performed in the time domain by convolving the plurality of streams of modulation symbols with the pulse-shaping matrix.

10. The method of claim 1, wherein the pulse-shaping matrix comprises a plurality of sequences of frequency-domain values, and wherein the preconditioning is performed in the frequency domain by multiplying a plurality of streams of transformed modulation symbols with the pulse-shaping matrix.

11. The method of claim 1, wherein the pulse-shaping matrix is derived to maximum capacity by allocating more transmit power to transmission channels with higher signal-to-noise-and-interference ratios (SNRs).

12. The method of claim 1, wherein the pulse-shaping matrix is derived to provide approximately equal received signal-to-noise-and-interference ratios (SNRs) for the plurality of modulation symbol streams.

13. The method of claim 1, wherein separate coding and modulation schemes are used for each transmission channel.

14. The method of claim 1, wherein a common coding and modulation scheme is used for all transmission channels.

6. A method for transmitting data in a multiple-input multiple-output (MIMO) communication system, comprising:

coding data in accordance with one or more coding schemes to provide coded data for a plurality of transmission channels in a MIMO channel;

modulating the coded data in accordance with one or more modulation schemes to provide a plurality of streams of modulation symbols;

deriving a pulse-shaping matrix based in part on an estimated response of the MIMO channel, comprising;

determining an estimated channel response matrix for the MIMO channel; and

decomposing the estimated channel response matrix to obtain a first sequence of matrices of eigen-vectors and a second sequence of matrices of singular values, wherein the pulse-shaping matrix is derived based on the first and second sequences of matrices, and wherein the singular values in each matrix in the second sequence are randomly ordered such that eigen-modes of the estimated channel response matrix are associated with approximately equal transmit power;

preconditioning the plurality of modulation symbol streams based on the pulse-shaping matrix to derive a plurality of preconditioned signals; and

transmitting the plurality of preconditioned signals over the MIMO channel.

7. A method for transmitting data in a multiple-input multiple-output (MIMO) communication system, comprising:

coding data in accordance with one or more coding schemes to provide coded data for a plurality of transmission channels in a MIMO channel;

modulating the coded data in accordance with one or more modulation schemes to provide a plurality of streams of modulation symbols;

deriving a pulse-shaping matrix based in part on an estimated response of the MIMO channel, comprising;

determining an estimated channel response matrix for the MIMO channel; and

decomposing the estimated channel response matrix to obtain a first sequence of matrices of eigen-vectors and a second sequence of matrices of singular values; and

deriving a third sequence of matrices, based on the second sequence of matrices of singular values, having values indicative of transmit power allocated to eigen-modes of the estimated channel response matrix, wherein the pulse-shaping matrix is derived based on the first and third sequences of matrices;

preconditioning the plurality of modulation symbol streams based on the pulse-shaping matrix to derive a plurality of preconditioned signals; and

transmitting the plurality of preconditioned signals over the MIMO channel.

8. The method of claim 7, wherein the third sequence of matrices is derived based on water-pouring analysis.

15. A method for transmitting data in a multiple-input multiple-output (MIMO) communication system, comprising:

coding data in accordance with one or more coding schemes to provide coded data for a plurality of transmission channels in a MIMO channel;

modulating the coded data in accordance with one or more modulation schemes to provide a plurality of streams of modulation symbols;

determining an estimated channel response matrix for the MIMO channel;

decomposing the estimated channel response matrix to obtain a first sequence of matrices of eigen-vectors and a second sequence of matrices of singular values;

deriving a third sequence of matrices, based on the second sequence of matrices of singular values, having values indicative of transmit power allocated to eigen-modes of the estimated channel response matrix;

deriving a pulse-shaping matrix based on the first and third sequences of matrices;

preconditioning the plurality of modulation symbol streams based on the pulse-shaping matrix to derive a plurality of preconditioned signals; and

transmitting the plurality of preconditioned signals over the MIMO channel.

16. A memory communicatively coupled to a digital signal processing device (DSPD) capable of interpreting digital information to:

code data in accordance with one or more coding schemes to provide coded data for a plurality of transmission channels in a MIMO channel;

modulate the coded data in accordance with one or more modulation schemes to provide a plurality of streams of modulation symbols;

derive a pulse-shaping matrix based in part on a first sequence of matrices of eigen-vectors and a second sequence of matrices of singular values corresponding to an estimated channel response matrix of the MIMO channel; and

precondition the plurality of modulation symbol streams based on the pulse-shaping matrix to derive a plurality of preconditioned signals for transmission over the MIMO channel.

17. A method for receiving a data transmission in a multiple-input multiple-output (MIMO) communication system, comprising:

determining an estimated channel response matrix for a MIMO channel used for the data transmission;

decomposing the estimated channel response matrix based on singular value decomposition to obtain a first sequence of matrices of eigen-vectors;

deriving a pulse-shaping matrix based on the first sequence of matrices; and

preconditioning a plurality of received signals based on the pulse-shaping matrix to obtain a plurality of streams of received symbols.

18. The method of claim 17, wherein the preconditioning is performed in the time domain based on a time-domain pulse-shaping matrix.

19. The method of claim 17, wherein the preconditioning is performed in the frequency domain and includes

transforming the plurality of received signals to the frequency domain;

multiplying the transformed received signals with a frequency-domain pulse-shaping matrix to derive a plurality of preconditioned signals; and

transforming the plurality of preconditioned signals to the time domain to obtain the plurality of received symbol streams.

20. The method of claim 17, wherein the preconditioning orthogonalizes the plurality of streams of received symbols.

21. The method of claim 17, further comprising:

equalizing the plurality of received symbol streams to derive a plurality of recovered symbol streams.

22. The method of claim 21, wherein the equalizing is performed separately for each received symbol stream.

23. The method of claim 21, wherein the equalizing is performed based on a minimum mean square error linear equalizer (MMSE-LE).

24. The method of claim 21, wherein the equalizing is performed based on a decision feedback equalizer (DFE).

25. The method of claim 21, wherein the equalizing is performed based on a maximum likelihood sequence estimation (MLSE) equalizer.

26. The method of claim 21, further comprising:

demodulating the plurality of recovered symbol streams in accordance with one or more demodulation schemes to provide a plurality of demodulated data streams; and

decoding the plurality of demodulated data streams in accordance with one or more decoding schemes to provide decoded data.

27. The method of claim 17, further comprising:

deriving channel state information (CSI) comprised of the estimated channel response matrix and signal-to-noise-and-interference ratios (SNRs) for a plurality of transmission channels of the MIMO channel; and

sending the CSI back to a transmitter of the data transmission.

28. A method for receiving a data transmission in a multiple-input multiple-output (MIMO) communication system, comprising:

determining an estimated channel response matrix for a MIMO channel used for the data transmission;

decomposing the estimated channel response matrix to obtain a first sequence of matrices of eigen-vectors;

deriving a pulse-shaping matrix based on the first sequence of matrices;

preconditioning a plurality of received signals based on the pulse-shaping matrix to obtain a plurality of streams of received symbols;

equalizing the plurality of received symbol streams to derive a plurality of recovered symbol streams;

demodulating the plurality of recovered symbol streams in accordance with one or more demodulation schemes to provide a plurality of demodulated data streams; and

decoding the plurality of demodulated data streams in accordance with one or more decoding schemes to provide decoded data.

29. A memory communicatively coupled to a digital signal processing device (DSPD) capable of interpreting digital information to:

determine an estimated channel response matrix for a MIMO channel used for the data transmission;

decompose the estimated channel response matrix based on singular value decomposition to obtain a first sequence of matrices of eigen-vectors;

derive a pulse-shaping matrix based on the first sequence of matrices; and

precondition a plurality of received signals based on the pulse-shaping matrix to obtain a plurality of streams of received symbols.

30. A transmitter unit in a multiple-input multiple-output (MIMO) communication system, comprising:

a TX data processor operative to code data in accordance with one or more coding schemes to provide coded data for a plurality of transmission channels in a MIMO channel, and to modulate the coded data in accordance with one or more modulation schemes to provide a plurality of streams of modulation symbols;

a TX MIMO processor operative to derive a pulse-shaping matrix based in part on a first sequence of matrices of eigen-vectors and a second sequence of matrices of singular values corresponding to an estimated channel response matrix of the MIMO channel, and to precondition the plurality of modulation symbol streams based on the pulse-shaping matrix to provide a plurality of preconditioned signals; and

one or more transmitters operative to condition and transmit the plurality of preconditioned signals over the MIMO channel.

31. The transmitter unit of claim 30, wherein the TX MIMO processor is further operative to determine the estimated channel response matrix for the MIMO channel, decompose the estimated channel response matrix to obtain the first sequence of matrices of eigen-vectors and the second sequence of matrices of singular values.

32. The transmitter unit of claim 31, wherein the TX MIMO processor is further operative to decompose the estimated channel response matrix in the frequency domain using singular value decomposition.

33. A transmitter unit in a multiple-input multiple-output (MIMO) communication system, comprising:

a TX data processor operative to code data in accordance with one or more coding schemes to provide coded data for a plurality of transmission channels in a MIMO channel, and to modulate the coded data in accordance with one or more modulation schemes to provide a plurality of streams of modulation symbols;

a TX MIMO processor operative to derive a pulse-shaping matrix based in part on an estimated response of the MIMO channel, and to precondition the plurality of modulation symbol streams based on the pulse-shaping matrix to provide a plurality of preconditioned signals; and

one or more transmitters operative to condition and transmit the plurality of preconditioned signals over the MIMO channel,

wherein the TX MIMO processor is further operative to determine an estimated channel response matrix for the MIMO channel, decompose the estimated channel response matrix to obtain a first sequence of matrices of eigen-vectors and a second sequence of matrices of singular values, wherein the TX MIMO processor is further operative to derive, based on the second sequence of matrices of singular values, a third sequence of matrices of values indicative of transmit power allocated to eigen-modes of the estimated channel response matrix, and to derive the pulse-shaping matrix based on the first and third sequences of matrices.

34. A transmitter apparatus in a multiple-input multiple-output (MIMO) communication system, comprising:

means for coding data in accordance with one or more coding schemes to provide coded data for a plurality of transmission channels in a MIMO channel;

means for modulating the coded data in accordance with one or more modulation schemes to provide a plurality of streams of modulation symbols;

means for deriving a pulse-shaping matrix based in part on a first sequence of matrices of eigen-vectors and a second sequence of matrices of singular values corresponding to an estimated channel response matrix of the MIMO channel;

means for preconditioning the plurality of modulation symbol streams based on the pulse-shaping matrix to derive a plurality of preconditioned signals; and

means for transmitting the plurality of preconditioned signals over the MIMO channel.

35. A digital signal processor for use in a multiple-input multiple-output (MIMO) communication system, comprising:

means for coding data in accordance with one or more coding schemes to provide coded data for a plurality of transmission channels in a MIMO channel;

means for modulating the coded data in accordance with one or more modulation schemes to provide a plurality of streams of modulation symbols;

means for deriving a pulse-shaping matrix based in part on a first sequence of matrices of eigen-vectors and a second sequence of matrices of singular values corresponding to an estimated channel response matrix of the MIMO channel; and

means for preconditioning the plurality of modulation symbol streams based on the pulse-shaping matrix to derive a plurality of preconditioned signals.

36. A receiver unit in a multiple-input multiple-output (MIMO) communication system, comprising:

a RX MIMO processor operative to determine an estimated channel response matrix for a MIMO channel used for data transmission, decompose the estimated channel response matrix to obtain a first sequence of matrices of eigen-vectors, derive a pulse-shaping matrix based on the first sequence of matrices, and precondition a plurality of received signals based on the pulse-shaping matrix to obtain a plurality of streams of received symbols; and

a RX data processor operative to demodulate the plurality of received symbol streams in accordance with one or more demodulation schemes, and to decode a plurality of demodulated data streams in accordance with one or more decoding schemes to provide decoded data.

37. The receiver unit of claim 36, wherein the RX MIMO processor includes

an equalizer operative to equalize the plurality of received symbol streams to provide a plurality of recovered symbol streams, and

wherein the RX data processor is operative to demodulate and decode the plurality of recovered symbol streams to provide the decoded data.

38. The receiver unit of claim 37, wherein the equalizer is a minimum mean square error linear equalizer (MMSE-LE).

39. The receiver unit of claim 37, wherein the equalizer is a decision feedback equalizer (DFE).

40. The receiver unit of claim 37, wherein the equalizer is a maximum likelihood sequence estimation (MLSE) equalizer.

41. The receiver unit of claim 37, wherein the equalizer is operative to separately equalize each received symbol stream.

42. A receiver apparatus in a multiple-input multiple-output (MIMO) communication system, comprising:

means for determining an estimated channel response matrix for a MIMO channel used for the data transmission;

means for decomposing the estimated channel response matrix based on singular value decomposition to obtain a first sequence of matrices of eigen-vectors;

means for deriving a pulse-shaping matrix based on the first sequence of matrices; and

means for preconditioning a plurality of received signals based on the pulse-shaping matrix to obtain a plurality of streams of received symbols.

43. A digital signal processor in a multiple-input multiple-output (MIMO) communication system, comprising:

means for determining an estimated channel response matrix for a MIMO channel used for the data transmission;

means for decomposing the estimated channel response matrix based on singular value decomposition to obtain a first sequence of matrices of eigen-vectors;

means for deriving a pulse-shaping matrix based on the first sequence of matrices; and

means for preconditioning a plurality of received signals based on the pulse-shaping matrix to obtain a plurality of streams of received symbols.