Coded MIMO systems with selective channel inversion applied per eigenmode

• US 20040042556A1
• Filed: 08/27/2002
• Published: 03/04/2004
• Est. Priority Date: 08/27/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Medvedev, Irina, Ketchum, John W., Walton, Jay Rod
• Granted Patent: US 8,194,770 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• 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; and

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

selecting one or more transmission channels in the group for use, and

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

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, further comprising:

allocating total transmit power to the plurality of groups, and wherein the one or more scaling factors for the one or more selected transmission channels in each group are determined based in part on the transmit power allocated to the group.

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

5. The method of claim 3, wherein the total transmit power is allocated to the plurality of groups based on water-filling.

6. The method of claim 5, 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 plurality of transmission channels in the group.

7. The method of claim 5, wherein the water-filling is performed based on average signal-to-noise-and-interference ratios (SNRs) for the plurality of groups.

8. The method of claim 5, 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.

9. The method of claim 1, wherein if a group is to be used for data transmission then all transmission channels in the group are selected for use.

10. 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.

11. The method of claim 10, wherein the data for each group of transmission channels is coded based on a separate coding scheme.

12. The method of claim 10, wherein the data for all 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.

13. The method of claim 10, further comprising:

preconditioning scaled modulation symbols.

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

15. 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 all 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,

selecting one or more transmission channels in the group for use, and

determining a scaling factor for each selected transmission channel, based in part on the transmit power allocated to the group, such that the one or more selected transmission channels in each group have similar received signal quality.

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

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

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

17. The transmitter unit of claim 16, wherein the TX MIMO processor is further operative to allocate total transmit power to the plurality of groups, and 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.

18. A transmitter unit in a multiple-input, multiple-output (MIMO) communication system that implements orthogonal frequency division multiplexing (OFDM), comprising:

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

a TX MIMO processor operative to

allocate total transmit power to a plurality of groups of transmission channels, wherein each group includes all transmission channels corresponding to a particular eigenmode of a MIMO channel,

select one or more transmission channels in each group for use for data transmission,

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

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

19. The transmitter unit of claim 18, wherein the TX MIMO processor is further operative to precondition scaled modulation symbols.

20. 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;

means for selecting one or more transmission channels in each group for use for data transmission; and

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

21. The apparatus of claim 20, 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.