METHOD AND APPARATUS FOR PROVIDING EFFICIENT PRECODING FEEDBACK IN A MIMO WIRELESS COMMUNICATION SYSTEM

• US 20080049709A1
• Filed: 08/17/2007
• Published: 02/28/2008
• Est. Priority Date: 08/17/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Olesen, Robert, Pan, Kyle, Grieco, Donald
• Granted Patent: US 7,881,247 B2
• Time in Patent Office: Days
• US Class Current: 370/344
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04B 7/0641 Differential feedback
• CPC Class Codes: H04B 7/066 Combined feedback for a number of channels, e.g. over several subcarriers like in orthogonal frequency division multiplexing [OFDM]
• CPC Class Codes: H04B 7/0663 using vector or matrix manipulations
• CPC Class Codes: H04L 1/0687 Full feedback

Abstract

A multiple-input multiple-output (MIMO) scheme uses precoding and feedback in a wireless communication system including a transmitter and a receiver. The system may use either a single codeword (SCW) or a double codeword (DCW). The precoding scheme is based on transmit beamforming (TxBF). Combined differential and non-differential feedback with periodic resetting is considered.

Claims

1. A method of providing precoding feedback comprising:

receiving a plurality of feedback bits;

updating a first precoding matrix based on the feedback bits, wherein the feedback bits are either non-differential feedback bits or differential feedback bits; and

precoding a plurality of frequency domain data streams using the first precoding matrix.

2. The method of claim 1 further comprising:

receiving a plurality of time domain data streams, each time domain data stream including a cyclic prefix (CP);

removing the CPs from the time domain data streams to generate a plurality of processed data streams;

converting the processed data streams to frequency domain data;

performing channel estimation on the frequency domain data to generate a channel estimate;

generating a second precoding matrix based on the channel estimate; and

generating and transmitting feedback bits based on the second precoding matrix.

3. The method of claim 2 wherein the second precoding matrix is a delta precoding matrix and the feedback bits are differential feedback bits.

4. The method of claim 2 wherein the second precoding matrix is a full precoding matrix and the feedback bits are non-differential feedback bits.

5. The method of claim 4 wherein non-differential feedback bits are generated by using a Jacobi rotation to perform matrix diagonalization on at least one of a channel response matrix and a channel correlation matrix associated with the channel estimate.

6. The method of claim 1 wherein the feedback bits are non-differential feedback bits, the method further comprising:

mapping the non-differential feedback bits to a full precoding matrix by using a non-differential codebook.

7. The method of claim 1 wherein the feedback bits are differential feedback bits, the method further comprising:

mapping the non-differential feedback bits to a delta precoding matrix by using a differential codebook; and

generating a full precoding matrix based on the delta precoding matrix.

8. The method of claim 1 wherein the method is implemented in a wireless communication system including a transmitter and a receiver.

9. The method of claim 8 wherein the receiver is incorporated in a wireless transmit/receive unit (WTRU).

10. The method of claim 8 wherein the transmitter is an evolved Node-B (eNodeB).

11. The method of claim 8 wherein the transmitter is a base station.

12. A method of providing precoding feedback comprising:

receiving a plurality of feedback bits;

updating a first precoding matrix based on the feedback bits, wherein the feedback bits include differential feedback bits and non-differential bits; and

precoding a plurality of frequency domain data streams using the first precoding matrix.

13. The method of claim 12 wherein differential feedback is reset every N transmission timing intervals (TTIs), where N is a predetermined integer.

14. The method of claim 12 wherein differential feedback is reset every N feedback intervals, where N is a predetermined integer.

15. The method of claim 12 wherein differential feedback is reset aperiodically for avoiding error accumulation or propagation due to differential processing.

16. The method of claim 12 wherein non-differential feedback occurs every N transmission timing intervals (TTIs) or every N feedback intervals, and differential feedback is used for the remaining TTIs or feedback intervals, where N is a predetermined integer.

17. The method of claim 12 wherein two (2) bits are used for differential feedback and three (3) bits are used for non-differential feedback.

18. The method of claim 17 wherein a codebook consisting of eight codewords that require three (3) feedback bits for quantization is used for non-differential feedback.

19. The method of claim 17 wherein a codebook consisting of four codewords that require two (2) feedback bits for quantization is used for differential feedback.

20. The method of claim 12 wherein the method is implemented in a wireless communication system including a transmitter and a receiver.

21. The method of claim 20 wherein the receiver is incorporated in a wireless transmit/receive unit (WTRU).

22. The method of claim 20 wherein the transmitter is an evolved Node-B (eNodeB).

23. The method of claim 20 wherein the transmitter is a base station.

24. A receiver for providing feedback to a transmitter for updating a first precoding matrix used by the transmitter to precode a plurality of frequency domain data streams, the receiver comprising:

a channel estimator configured to generate a channel estimate by performing a channel estimation on frequency domain data associated with a plurality of time domain data streams transmitted by the transmitter; and

a feedback generator electrically coupled to the channel estimator, the feedback generator configured to generate feedback bits for transmission to the transmitter based on the channel estimate, wherein the feedback bits are either non-differential feedback bits or differential feedback bits.

25. The receiver of claim 24 further comprising:

a plurality of antennas configured to receive the time domain data streams;

a plurality of cyclic prefix (CP) removal units electrically coupled to respective ones of the antennas, each CP removal unit being configured to remove a CP from each of a plurality of time domain data streams received by the antennas to generate processed data streams; and

a plurality of fast Fourier transform (FFT) units electrically coupled to respective ones of the CP removal units and the channel estimator, each FFT unit being configured to convert the processed data streams to frequency domain data.

26. The receiver of claim 24 wherein the feedback generator comprises:

a precoding matrix generator configured to generate a second precoding matrix based on the channel estimate; and

a feedback bit generator electrically coupled to the precoding matrix generator, the feedback bit generator being configured to generate and transmit feedback bits based on the second precoding matrix.

27. The receiver of claim 26 wherein the second precoding matrix is a delta precoding matrix and the feedback bits are differential feedback bits.

28. The receiver of claim 26 wherein the second precoding matrix is a full precoding matrix and the feedback bits are non-differential feedback bits.

29. The receiver of claim 24 wherein the receiver is a wireless transmit/receive unit (WTRU).

30. The receiver of claim 24 wherein the transmitter is an evolved Node-B (eNodeB).

31. The receiver of claim 24 wherein the transmitter is a base station.

32. A receiver for providing feedback to a transmitter for updating a first precoding matrix used by the transmitter to precode a plurality of frequency domain data streams, the receiver comprising:

a channel estimator configured to generate a channel estimate by performing a channel estimation on frequency domain data associated with a plurality of time domain data streams transmitted by the transmitter; and

a feedback generator electrically coupled to the channel estimator, the feedback generator configured to generate feedback bits for transmission to the transmitter based on the channel estimate, wherein the feedback bits include differential feedback bits and non-differential bits.

33. The receiver of claim 32 wherein differential feedback is reset every N transmission timing intervals (TTIs), where N is a predetermined integer.

34. The receiver of claim 32 wherein differential feedback is reset every N feedback intervals, where N is a predetermined integer.

35. The receiver of claim 32 wherein differential feedback is reset aperiodically for avoiding error accumulation or propagation due to differential processing.

36. The receiver of claim 32 wherein non-differential feedback occurs every N transmission timing intervals (TTIs) or every N feedback intervals, and differential feedback is used for the remaining TTIs or feedback intervals, where N is a predetermined integer.

37. The receiver of claim 32 wherein two (2) bits are used for differential feedback and three (3) bits are used for non-differential feedback.

38. The receiver of claim 32 wherein a codebook consisting of eight codewords that require three (3) feedback bits for quantization is used for non-differential feedback.

39. The receiver of claim 32 wherein a codebook consisting of four codewords that require two (2) feedback bits for quantization is used for differential feedback.

40. The receiver of claim 32 wherein the receiver is a wireless transmit/receive unit (WTRU).

41. The receiver of claim 32 wherein the transmitter is an evolved Node-B (eNodeB).

42. The receiver of claim 32 wherein the transmitter is a base station.

43. A transmitter that performs precoding based on feedback provided by a receiver, the feedback being generated based on a plurality of time domain data streams that the receiver receives from the transmitter, the transmitter comprising:

a precoding matrix generator configured to receive feedback bits from the receiver and update a precoding matrix based on the feedback bits, wherein the feedback bits are either non-differential feedback bits or differential feedback bits; and

a precoder electrically coupled to the precoding matrix generator, the precoder being configured to precode a plurality of frequency domain data streams using the precoding matrix.

44. The transmitter of claim 43 wherein the precoder comprises:

a feedback bits to delta precoding mapping unit for mapping differential feedback bits to a delta precoding matrix; and

a full precoding matrix generation and update unit for generating and updating a full precoding matrix based on the delta precoding matrix, wherein the precoder uses the full precoding matrix to precode the frequency domain data streams.

45. The transmitter of claim 43 wherein the precoder comprises:

a feedback bits to full precoding mapping unit for mapping non-differential feedback bits to a full precoding matrix, wherein the precoder uses the full precoding matrix to precode the frequency domain data streams.

46. The transmitter of claim 43 wherein the receiver is a wireless transmit/receive unit (WTRU).

47. The transmitter of claim 43 wherein the transmitter is an evolved Node-B (eNodeB).

48. The transmitter of claim 43 wherein the transmitter is a base station.

49. A transmitter that performs precoding based on feedback provided by a receiver, the feedback being generated based on signals that the receiver receives from the transmitter, the transmitter comprising:

a precoding matrix generator configured to receive feedback bits from the receiver and generate a precoding matrix based on the feedback bits, wherein the feedback bits include differential feedback bits and non-differential bits; and

a precoder electrically coupled to the precoding matrix generator, the precoder being configured to precode a plurality of frequency domain data streams using the precoding matrix.

50. The transmitter of claim 49 wherein differential feedback is reset every N transmission timing intervals (TTIs), where N is a predetermined integer.

51. The transmitter of claim 49 wherein differential feedback is reset every N feedback intervals, where N is a predetermined integer.

52. The transmitter of claim 49 wherein differential feedback is reset aperiodically for avoiding error accumulation or propagation due to differential processing.

53. The transmitter of claim 49 wherein non-differential feedback occurs every N transmission timing intervals (TTIs) or every N feedback intervals, and differential feedback is used for the remaining TTIs or feedback intervals, where N is a predetermined integer.

54. The transmitter of claim 49 wherein two (2) bits are used for differential feedback and three (3) bits are used for non-differential feedback.

55. The transmitter of claim 49 wherein a codebook consisting of eight codewords that require three (3) feedback bits for quantization is used for non-differential feedback.

56. The transmitter of claim 49 wherein a codebook consisting of four codewords that require two (2) feedback bits for quantization is used for differential feedback.

57. The transmitter of claim 49 wherein the precoder comprises:

a feedback bits to delta precoding mapping unit for mapping differential feedback bits to a delta precoding matrix; and

a full precoding matrix generation and update unit for generating and updating a full precoding matrix based on the delta precoding matrix, wherein the precoder uses the full precoding matrix to precode the frequency domain data streams.

58. The transmitter of claim 49 wherein the precoder comprises:

a feedback bits to full precoding mapping unit for mapping non-differential feedback bits to a full precoding matrix, wherein the precoder uses the full precoding matrix to precode the frequency domain data streams.

59. The transmitter of claim 49 wherein the receiver is a wireless transmit/receive unit (WTRU).

60. The transmitter of claim 49 wherein the transmitter is an evolved Node-B (eNodeB).

61. The transmitter of claim 49 wherein the transmitter is a base station.