Coded MIMO systems with selective channel inversion applied per eigenmode

• US 8,194,770 B2
• Filed: 08/27/2002
• Issued: 06/05/2012
• Est. Priority Date: 08/27/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Medvedev, Irina, Walton, Jay Rod, Ketchum, John W.
• Primary Examiner(s): Fan, Chieh M.
• Assistant Examiner(s): Aghdam, Freshteh N
• Application Number:
  US10/229,209
• Publication Number:
  US 20040042556A1
• Time in Patent Office: 3,570 Days
• Field of Search: 375/260, 375/267, 375/295, 375/299
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0439 utilizing channel inversion
• 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 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Techniques to perform selective channel inversion per eigenmode in a MIMO system to achieve high spectral efficiency while reducing complexity at both the transmitter and receiver are presented. The available transmission channels are arranged into a number of groups, where each group may include all transmission channels (or frequency bins) for a respective eigenmode of a MIMO channel. The total transmit power is allocated to the groups using a particular group power allocation scheme. Selective channel inversion is then performed independently for each group selected for use for data transmission. For each such group, one or more transmission channels in the group are selected for use, and a scaling factor is determined for each selected channel such that all selected channels for the group achieve similar received signal quality (e.g., received SNR).

Claims

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

arranging a plurality of available transmission channels into a plurality of groups, each group comprising multiple transmission channels;

allocating total transmit power to the plurality of groups; and

for each group of transmission channels to be used for data transmission,

determining a group threshold,

selecting one or more of the multiple transmission channels in the group for use, wherein the selecting is based on the group threshold, and

determining a scaling factor for each of the one or more selected transmission channels such that the one or more selected transmission channels in each group have similar received signal quality,

wherein a first determined group threshold for a first group of transmission channels is different than a second determined group threshold for a second group of transmission channels.

2. The method of claim 1, wherein each group includes all transmission channels corresponding to a particular eigenmode of a MIMO channel.

3. The method of claim 1, wherein the total transmit power is uniformly allocated to the plurality of groups.

4. The method of claim 1, wherein the total transmit power is allocated to the plurality of groups based on water-filling.

5. The method of claim 4, wherein the water-filling is performed across the plurality of available transmission channels, and wherein the transmit power allocated to each group is based on transmit powers allocated to the multiple transmission channels in the group.

6. The method of claim 4, wherein the water-filling is performed based on average signal-to-noise-and-interference ratios (SNRs) for the plurality of groups.

7. The method of claim 4, wherein the water-filling is performed based on signal-to-noise-and-interference ratios (SNRs) for the plurality of available transmission channels after channel inversion.

8. The method of claim 1, further comprising:

coding and modulating data based on one or more coding and modulation schemes to provide modulation symbols; and

scaling each modulation symbol based on the scaling factor for the transmission channel used to transmit the modulation symbol.

9. The method of claim 8, wherein the data for each group of transmission channels is coded based on a separate coding scheme.

10. The method of claim 8, wherein the data for the plurality of groups of transmission channels is coded based on a common coding scheme, and wherein coded data for each group is punctured with a rate selected for the group.

11. The method of claim 8, further comprising:

preconditioning scaled modulation symbols.

12. The method of claim 1, wherein the MIMO system implements orthogonal frequency division multiplexing (OFDM).

39. The method of claim 1, wherein determining a threshold comprises:

arranging the multiple transmission channels in the group in a list having a descending order based on an eigenvalue of each transmission channel;

computing a spectral efficiency when using the first n transmission channels in the list, where n is an integer having an initial value greater than or equal to 1 that is increased incrementally; and

determining the threshold based at least in part on when the computed spectral efficiency of using the first n+1 transmission channels is lower than using the first n transmission channels.

13. A method for processing data for transmission in a multiple-input, multiple-output (MIMO) communication system that implements orthogonal frequency division multiplexing (OFDM), comprising:

arranging a plurality of available transmission channels into a plurality of groups, wherein each group includes multiple transmission channels corresponding to a particular eigenmode of a MIMO channel;

allocating total transmit power to the plurality of groups; and

for each group of transmission channels to be used for data transmission,

determining a group threshold,

selecting one or more of the multiple transmission channels in the group for use, wherein the selecting is based on the group threshold, and

determining a scaling factor for each of the one or more selected transmission channels, such that the one or more selected transmission channels in each group have similar received signal quality,

wherein a first determined group threshold for a first group of transmission channels is different than a second determined group threshold for a second group of transmission channels.

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

a transmit data processor operative to code and modulate data based on one or more coding and modulation schemes to provide modulation symbols; and

a transmit MIMO processor operative to select one or more of multiple transmission channels in each of a plurality of groups of transmission channels for use for data transmission, wherein the selecting is based on a group threshold selected for each group, to determine a scaling factor for each of the one or more selected transmission channels in each group such that the one or more selected transmission channels in the group have similar received signal quality, to scale each modulation symbol based on the scaling factor for the transmission channel used to transmit the modulation symbol, and to allocate total transmit power to the plurality of groups,

wherein a first determined group threshold for a first group of transmission channels is different than a second determined group threshold for a second group of transmission channels.

15. The transmitter unit of claim 14, wherein the one or more scaling factors for the one or more selected transmission channels in each group is determined based in part on the transmit power allocated to the group.

16. An apparatus in a multiple-input, multiple-output (MIMO) communication system that implements orthogonal frequency division multiplexing (OFDM), comprising:

a transmit data processor operative to code and modulate data based on one or more coding and modulation schemes to provide modulation symbols; and

a transmit MIMO processor operative to allocate total transmit power to a plurality of groups of transmission channels, wherein each group includes multiple transmission channels corresponding to a particular eigenmode of a MIMO channel, to select a group threshold for each group, to select one or more of the multiple transmission channels in each group for use for data transmission, wherein the selecting is based on the group threshold, to determine a scaling factor for each of the one or more selected transmission channels in each group such that the one or more selected transmission channels in the group have similar received signal quality, and to scale each modulation symbol based on the scaling factor for the transmission channel used to transmit the modulation symbol,

wherein a first determined group threshold for a first group of transmission channels is different than a second determined group threshold for a second group of transmission channels.

17. The apparatus of claim 16, wherein the transmit MIMO processor is further operative to precondition scaled modulation symbols.

20. The apparatus of claim 16, wherein each group includes all transmission channels corresponding to a particular eigenmode of a MIMO channel.

21. The apparatus of claim 16, wherein the transmit MIMO processor is configured to uniformly allocate the total transmit power to the plurality of groups.

22. The apparatus of claim 16, wherein the transmit MIMO processor is configured to allocate the total transmit power to the plurality of groups utilizing a water-filling technique.

23. The apparatus of claim 22, wherein the transmit MIMO processor is configured to utilize average signal-to-noise-and-interference ratios (SNRs) for the plurality of groups for water-filling.

24. The apparatus of claim 22, wherein the transmit MIMO processor is configured to utilize signal-to-noise-and-interference ratios (SNRs) for the plurality of available transmission channels after channel inversion for water-filling.

25. The apparatus of claim 16, wherein the transmit data processor is configured to code and modulate data for each group of transmission channels based on a separate coding scheme.

26. The apparatus of claim 16, wherein the transmit data processor is configured to code and modulate data for the plurality of groups of transmission channels based on a common coding scheme, and to puncture coded data for each group with a rate selected for the group.

18. An apparatus in a multiple-input, multiple-output (MIMO) communication system, comprising:

means for arranging a plurality of available transmission channels into a plurality of groups, each group comprising multiple transmission channels;

means for selecting a group threshold for each group;

means for selecting one or more of the multiple transmission channels in each group for use for data transmission, wherein the selecting is based on the group threshold;

means for allocating total transmit power to the plurality of groups; and

means for determining a scaling factor for each of the one or more selected transmission channels in each group such that the one or more selected transmission channels in the group have similar received signal quality,

wherein a first determined group threshold for a first group of transmission channels is different than a second determined group threshold for a second group of transmission channels.

19. The apparatus of claim 18, further comprising:

means for coding and modulating data based on one or more coding and modulation schemes to provide modulation symbols; and

means for scaling each modulation symbol based on the scaling factor for the transmission channel used to transmit the modulation symbol.

27. The apparatus of claim 18, wherein each group includes all transmission channels corresponding to a particular eigenmode of a MIMO channel.

28. The apparatus of claim 18, wherein the means for allocating comprises means for uniformly allocating the total transmit power to the plurality of groups.

29. The apparatus of claim 18, wherein the means for allocating comprises means for allocating the total transmit power to the plurality of groups utilizing a water-filling technique.

30. The apparatus of claim 29, wherein the means for allocating comprises means for utilizing average signal-to-noise-and-interference ratios (SNRs) for the plurality of groups for water-filling.

31. The apparatus of claim 29, wherein the means for allocating comprises means for utilizing signal-to-noise-and-interference ratios (SNRs) for the plurality of available transmission channels after channel inversion for water-filling.

32. The apparatus of claim 19, wherein the means for coding and modulating comprises means for coding and modulating data for each group of transmission channels based on a separate coding scheme.

33. The apparatus of claim 19, wherein the means for coding and modulating comprises:

means for coding and modulating data for the plurality of groups of transmission channels based on a common coding scheme, and

means for puncturing coded data for each group with a rate selected for the group.

34. A non-transitory machine-readable storing executable instructions, the instructions comprising:

code for arranging a plurality of available transmission channels into a plurality of groups, wherein each group includes multiple transmission channels corresponding to a particular eigenmode of a MIMO channel;

code for allocating total transmit power to the plurality of groups; and

for each group of transmission channels to be used for data transmission,

code for determining a group threshold;

code for selecting one or more of the multiple transmission channels in the group for use, wherein the selecting is based on the group threshold, and

code for determining a scaling factor for each of the one or more selected transmission channels, such that the one or more selected transmission channels in each group have similar received signal quality,

wherein a first determined group threshold for a first group of transmission channels is different than a second determined group threshold for a second group of transmission channels.

35. The machine-readable medium of claim 34, wherein each group includes all transmission channels corresponding to a particular eigenmode of a MIMO channel.

36. The machine-readable medium of claim 34, wherein said code for allocating further comprises code for uniformly allocating the total transmit power to the plurality of groups.

37. The machine-readable medium of claim 34, wherein said code for allocating further comprises code for allocating the total transmit power to the plurality of groups based on water-filling.

38. The non-transitory machine-readable medium storing executable instructions of claim 34, the instructions further comprising:

code for coding and modulating data based on one or more coding and modulation schemes to provide modulation symbols; and

code for scaling each modulation symbol based on the scaling factor for the transmission channel used to transmit the modulation symbol.