Method, apparatus and communication unit

1. One or more non-transitory, computer-readable media having instructions that, when executed, cause a first device to:

select a wideband precoding matrix for a set of sub-bands;

generate first feedback information to provide an indication of the wideband precoding matrix, the first feedback information to be fed back to a second device;

select a sub-band precoding matrix for a sub-band of the set of sub-bands;

generate second feedback information to provide an indication of the sub-band precoding matrix, the second feedback information to be fed back to the second device; and

process a modulated data stream transmitted by the second device, wherein the modulated data stream is transmitted based on the wideband precoding matrix or the sub-band precoding matrix.

2. The one or more non-transitory, computer-readable media of claim 1 , wherein the instructions, when executed, further cause the first device to:

select a rank for the set of sub-bands; and

generate third feedback information to provide an indication of the selected rank.

3. The one or more non-transitory, computer-readable media of claim 2 , wherein the instructions, when executed, further cause the first device to select the sub-band pre-coding matrix for the rank.

4. The one or more non-transitory, computer-readable media of claim 1 , wherein the sub-band pre-coding matrix is a first sub-band pre-coding matrix, the sub-band is a first sub-band, and the instructions, when executed, further cause the first device to:

select a second sub-band pre-coding matrix for a second sub-band of the set of sub-bands; and

generate third feedback information to provide an indication of the second sub-band pre-coding matrix.

5. The one or more non-transitory, computer-readable media of claim 1 , wherein the sub-band precoding matrix is selected according to 3GPP-LTE standard.

6. The one or more non-transitory, computer-readable media of claim 1 , wherein the instructions, when executed, are further to select the sub-band precoding matrix from a precoding codebook for the sub-band.

7. The one or more non-transitory, computer-readable media of claim 1 , wherein the instructions, when executed, further cause the device to select the wideband precoding matrix based on a maximum likelihood estimate of a transmit correlation matrix.

8. The one or more non-transitory, computer-readable media of claim 1 , wherein the first feedback information includes an indication of a first pre-coding matrix index that corresponds to the wideband pre-coding matrix and the second feedback information includes an indication of a second pre-coding matrix index that corresponds to the sub-band pre-coding matrix.

9. An apparatus, comprising:

precoding matrix selector circuitry to:

select a wideband precoding matrix for a set of sub-bands;

generate first feedback information to provide an indication of the wideband precoding matrix, the first feedback information to be fed back to a device; and

select a sub-band precoding matrix for a sub-band of the set of sub-bands; and

generate second feedback information to provide an indication of the sub-band precoding matrix, the second feedback information to be fed back to the device; and

receiver circuitry to process a modulated data stream transmitted by the device, wherein the modulated data stream is transmitted based on the wideband precoding matrix or the sub-band precoding matrix.

10. The apparatus of claim 9 , wherein the precoding matrix selector circuitry is further to:

select a rank for the set of sub-bands; and

generate third feedback information to provide an indication of the selected rank.

11. The apparatus of claim 10 , wherein the pre-coding matrix selector circuitry is to select the sub-band pre-coding matrix for the rank.

12. The apparatus of claim 9 , wherein the sub-band pre-coding matrix is a first sub-band pre-coding matrix, the sub-band is a first sub-band, and the pre-coding matrix selector circuitry is further to:

select a second sub-band pre-coding matrix for a second sub-band of the set of sub-bands; and

generate third feedback information to provide an indication of the second sub-band pre-coding matrix.

13. The apparatus of claim 9 , wherein the pre-coding matrix selector circuitry is to select the sub-band precoding matrix from a precoding codebook for the sub-band.

14. The apparatus of claim 9 , wherein the first feedback information includes an indication of a first pre-coding matrix index that corresponds to the wideband pre-coding matrix and the second feedback information includes an indication of a second pre-coding matrix index that corresponds to the sub-band pre-coding matrix.

15. The apparatus of claim 9 , wherein the apparatus comprises a baseband chip.

16. One or more non-transitory, computer-readable media having instructions that, when executed, cause a device to:

process first feedback information to determine an indication of a wideband precoding matrix for a set of sub-bands;

process second feedback information to determine an indication of a sub-band precoding matrix for a sub-band of the set of sub-bands;

cause transmission of first signals based on the wideband pre-coding matrix; and

cause transmission of second signals based on the sub-band precoding matrix.

17. The one or more non-transitory, computer-readable media of claim 16 , wherein the instructions, when executed, further cause the device to:

process third feedback information to determine an indication of a rank selected for the set of sub-bands; and

cause transmission of the first or second signals based on the selected rank.

18. The one or more non-transitory, computer-readable media of claim 16 , wherein the first feedback information includes an indication of a first pre-coding matrix index that corresponds to the wideband pre-coding matrix and the second feedback information includes an indication of a second pre-coding matrix index that corresponds to the sub-band pre-coding matrix.