Method and Apparatus for Enabling an Enhanced Frequency Domain Equalizer

• US 20120127870A1
• Filed: 11/23/2010
• Published: 05/24/2012
• Est. Priority Date: 11/23/2010
• Status: Abandoned Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Zhao, Wanlun, Black, Peter John, Chen, Jinghu
• Application Number:
  US12/952,746
• Publication Number:
  US 20120127870A1
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04L 25/03133 with a non-recursive structure H04L25/03127 takes precedence

Abstract

A method and apparatus for enabling an enhanced FDE in a TD-SCDMA system is provided. The method may comprise receiving one or more signals from one or more cells over one or more channels where each channel is described using a channel vector and a spreading vector, and where each signal includes one or more data blocks each including a number of symbols, converting the one or more received signals from a time domain into a frequency domain using a block FFT, inverting a covariance matrix, wherein the covariance matrix is derived from a linear convolution of the one or more channel vectors and the one or more spreading vectors, and determining one or more MMSE signals by manipulating the frequency domain one or more received signals by applying the inverted equivalent channel matrix.

Claims

1. A method of wireless communication, comprising:

receiving one or more signals from one or more cells over one or more channels where each channel is described using a channel vector and a spreading vector, and where each signal includes one or more data blocks each including a number of symbols;

converting the one or more received signals from a time domain into a frequency domain using a block fast Fourier transform (FFT);

inverting a covariance matrix, wherein the covariance matrix is derived from a linear convolution of the one or more channel vectors and the one or more spreading vectors; and

determining one or more minimum mean square error (MMSE) signals by manipulating the frequency domain one or more received signals by applying the inverted equivalent channel matrix.

2. The method of claim 1, wherein the inverting further comprises using FFTs to arrange the covariance matrix into a block diagonal matrix, wherein the number of blocks in the block diagonal matrix is equal to the number of symbols.

3. The method of claim 2, wherein the inverting further comprises:

determining at least one of the one or more channels that is not flat;

inverting each block in the block diagonal matrix associated with the at least one of the one or more channels that is not flat.

4. The method of claim 2, wherein the inverting further comprises iteratively inversing the block diagonal matrix.

5. The method of claim 1, further comprising determining a signal to interference and noise ratio (SINR) using the inverted equivalent channel matrix and a covariance matrix associated with the frequency domain one or more received signals.

6. The method of claim 1, further comprising determining a SINR for each of the one or more channels using the inverted equivalent channel matrix and a covariance matrix associated with the frequency domain one or more received signals.

7. The method of claim 1, wherein the determined one or more MMSE signals (ŝ

_mmse) are described by the expression ŝ

_mmse=F_K^H·

Δ

_B^H(Σ

_i=1ⁿΣ

_k=1^KiΔ

_i,kΔ

_i,k^H+σ

2I−

1·

FQr.

8. The method of claim 5, further comprising populating the inverted equivalent channel matrix and the covariance matrix are populated using at least one of measured values or estimated values.

9. The method of claim 5, wherein the SINR is described by the expression

10. The method of claim 6, wherein the SINR is described by the expression

11. An apparatus for wireless communication, comprising:

means for receiving one or more signals from one or more cells over one or more channels where each channel is described using a channel vector and a spreading vector, and where each signal includes one or more data blocks each including a number of symbols;

means for converting the one or more received signals from a time domain into a frequency domain using a block FFT;

means for inverting a covariance matrix, wherein the covariance matrix is derived from a linear convolution of the one or more channel vectors and the one or more spreading vectors; and

means for determining one or more minimum mean square error (MMSE) signals by manipulating the frequency domain one or more received signals by applying the inverted equivalent channel matrix.

12. The apparatus of claim 11, wherein the means for inverting further comprises means for using FFTs to arrange the covariance matrix into a block diagonal matrix, wherein the number of blocks in the block diagonal matrix is equal to the number of symbols.

13. The apparatus of claim 12, wherein the means for inverting further comprises:

means for determining at least one of the one or more channels that is not flat; and

means for inverting each block in the block diagonal matrix associated with the at least one of the one or more channels that is not flat.

14. The apparatus of claim 12, wherein the means for inverting further comprises means for iteratively inversing the block diagonal matrix.

15. The apparatus of claim 11, further comprising means for determining a SINR using the inverted equivalent channel matrix and a covariance matrix associated with the frequency domain one or more received signals.

16. The apparatus of claim 11, further comprising means for determining a SINR for each of the one or more channels using the inverted equivalent channel matrix and a covariance matrix associated with the frequency domain one or more received signals.

17. The apparatus of claim 11, wherein the determined one or more MMSE signals (ŝ

_mmse) are described by the expression ŝ

_mmse=F_K^H·

Δ

_B^H(Σ

_i=1ⁿΣ

_k=1^KiΔ

_i,kΔ

_i,k^H+σ

2I−

1·

FQr.

18. The apparatus of claim 15, further comprising means for populating the inverted equivalent channel matrix and the covariance matrix are populated using at least one of measured values or estimated values.

19. The apparatus of claim 15, wherein the SINR is described by the expression

20. The apparatus of claim 16, wherein the SINR is described by the expression

21. A computer program product, comprising:

a computer-readable medium comprising code for;

receiving one or more signals from one or more cells over one or more channels where each channel is described using a channel vector and a spreading vector, and where each signal includes one or more data blocks each including a number of symbols;

converting the one or more received signals from a time domain into a frequency domain using a block FFT;

inverting a covariance matrix, wherein the covariance matrix is derived from a linear convolution of the one or more channel vectors and the one or more spreading vectors; and

determining one or more minimum mean square error (MMSE) signals by manipulating the frequency domain one or more received signals by applying the inverted equivalent channel matrix.

22. The computer program product of claim 21, wherein the computer-readable medium further comprises code for:

using FFTs to arrange the covariance matrix into a block diagonal matrix, wherein the number of blocks in the block diagonal matrix is equal to the number of symbols.

23. The computer program product of claim 22, wherein the computer-readable medium further comprises code for:

determining at least one of the one or more channels that is not flat; and

inverting each block in the block diagonal matrix associated with the at least one of the one or more channels that is not flat.

24. The computer program product of claim 22, wherein the computer-readable medium further comprises code for iteratively inversing the block diagonal matrix

25. The computer program product of claim 21, wherein the computer-readable medium further comprises code for:

determining a SINR using the inverted equivalent channel matrix and a covariance matrix associated with the frequency domain one or more received signals.

26. The computer program product of claim 21, wherein the computer-readable medium further comprises code for:

determining a SINR for each of the one or more channels using the inverted equivalent channel matrix and a covariance matrix associated with the frequency domain one or more received signals

27. The computer program product of claim 21, wherein the determined one or more MMSE signals (ŝ

_mmse) are described by the expression ŝ

_mmse=F_K^H·

Δ

_B^H(Σ

_i=1ⁿΣ

_k=1^KiΔ

_i,kΔ

_i,k^H+σ

²I)<sup>−

1</sup>·

F_Qr.

28. The computer program product of claim 25, wherein the computer-readable medium further comprises code for populating the inverted equivalent channel matrix and the covariance matrix are populated using at least one of measured values or estimated values.

29. The computer program product of claim 25, wherein the SINR is described by the expression

30. The computer program product of claim 26, wherein the SINR is described by the expression

31. An apparatus for wireless communication, comprising:

at least one processor; and

a memory coupled to the at least one processor,

a receiver configured to receive one or more signals from one or more cells over one or more channels where each channel is described using a channel vector and a spreading vector, and where each signal includes one or more data blocks each including a number of symbols;

wherein the at least one processor is configured to;

convert the one or more received signals from a time domain into a frequency domain using a block FFT;

invert equivalent covariance matrix, wherein the covariance matrix is derived from a linear convolution of the one or more channel vectors and the one or more spreading vectors; and

determine one or more minimum mean square error (MMSE) signals by manipulating the frequency domain one or more received signals by applying the inverted equivalent channel matrix.

32. The apparatus of claim 31, wherein the processor is further configured to:

use FFTs to arrange the covariance matrix into a block diagonal matrix, wherein the number of blocks in the block diagonal matrix is equal to the number of symbols.

33. The apparatus of claim 32, wherein the processor is further configured to:

determine at least one of the one or more channels that is not flat;

invert each block in the block diagonal matrix associated with the at least one of the one or more channels that is not flat.

34. The apparatus of claim 32, wherein the processor is further configured to:

iteratively invert the block diagonal matrix.

35. The apparatus of claim 31, wherein the processor is further configured to:

determine a signal to interference and noise ratio (SINR) using the inverted equivalent channel matrix and a covariance matrix associated with the frequency domain one or more received signals.

36. The apparatus of claim 31, wherein the processor is further configured to:

determine a SINR for each of the one or more channels using the inverted equivalent channel matrix and a covariance matrix associated with the frequency domain one or more received signals.

37. The apparatus of claim 31, wherein the determined one or more MMSE signals (ŝ

_mmse) are described by the expression ŝ

_mmse=F_K^H·

Δ

_B^H(Σ

_i=1ⁿΣ

_k=1^KiΔ

_i,kΔ

_i,k^H+σ

2I−

1·

FQr.

38. The apparatus of claim 35, wherein the processor is further configured to:

populate the inverted equivalent channel matrix and the covariance matrix are populated using at least one of measured values or estimated values.

39. The apparatus of claim 35, wherein the SINR is described by the expression

40. The apparatus of claim 36, wherein the SINR is described by the expression