Method, apparatus and communication unit

1. A method for generating precoding feedback information in a multiple frequency radio transmission system, comprising:

selecting a wideband precoding matrix that corresponds to a frequency band comprising at least one frequency; and

selecting a plurality of narrow band precoding matrices each having a rank corresponding to a rank of the selected wideband precoding matrix, wherein each of the plurality of narrow band precoding matrices is selected for a given frequency band,

wherein selecting the plurality of narrow band precoding matrices comprises selecting at least one of the plurality of narrow band precoding matrices based on a maximum likelihood estimate of a transmit correlation matrix over a respective narrow band.

2. The method of claim 1 , wherein the at least one frequency comprises more than one frequency.

3. The method of claim 1 , wherein the at least one frequency comprises one frequency.

4. The method of claim 1 , wherein each of the plurality of narrow band precoding matrices is selected according to the 3GPP-LTE standard.

5. The method of claim 1 , wherein the selected wideband precoding matrix is based on a maximum likelihood estimate of a transmit correlation matrix.

6. A method for generating precoding feedback information in a multiple frequency radio transmission system, comprising:

selecting a wideband precoding matrix that corresponds to a frequency band comprising at least one frequency; and

selecting a plurality of narrow band precoding matrices each having a rank corresponding to a rank of the selected wideband precoding matrix, wherein each of the plurality of narrow band precoding matrices is selected for a given frequency band,

wherein selecting the wideband precoding matrix comprises selecting the wideband precoding matrix based on an optimization of a data rate in the multiple frequency radio transmission system.

7. An apparatus for generating precoding feedback information in a multiple frequency radio transmission system, comprising:

a first device configured to select a wideband precoding matrix that corresponds to a frequency band comprising a plurality of frequencies; and

a second device configured to select a plurality of narrow band precoding matrices, each having a rank corresponding to a rank of the selected wideband precoding matrix, wherein each of the plurality of narrow band precoding matrices is selected for a given frequency band,

wherein the wideband precoding matrix is selected by maximizing a cost function as defined by

F c ( M )=log 2 det( I+Mσ n −2 ) wherein

M=P H R Tx P wherein

P being the wideband precoding matrix, R Tx the maximum likelihood estimate of the transmit correlation matrix, I the identity matrix, σ n the strength of the additive spatially white Gaussian noise.

8. The apparatus of claim 7 , wherein the precoded transmission signal is received by a receiver being capable of performing a serial interference cancellation (SIC).

9. An apparatus for generating precoding feedback information in a multiple frequency radio transmission system, comprising:

a first device configured to select a wideband precoding matrix that corresponds to a frequency band comprising a plurality of frequencies; and

a second device configured to select a plurality of narrow band precoding matrices, each having a rank corresponding to a rank of the selected wideband precoding matrix, wherein each of the plurality of narrow band precoding matrices is selected for a given frequency band,

wherein the transmission signal is received by a receiver comprising a linear minimum mean square error (MMSE) equalizer evaluating the signal-to-interference-plus-noise ratios for the given frequency band.

10. The apparatus of claim 9 , wherein the selected plurality of narrow band precoding matrices is used to precode a transmission signal to be transmitted by the multiple frequency radio transmission system.

11. An apparatus for generating precoding feedback information in a multiple frequency radio transmission system, comprising:

a first device configured to select a wideband precoding matrix that corresponds to a frequency band comprising a plurality of frequencies; and

a second device configured to select a plurality of narrow band precoding matrices, each having a rank corresponding to a rank of the selected wideband precoding matrix, wherein each of the plurality of narrow band precoding matrices is selected for a given frequency band,

wherein the first device and the second device comprise optimization units configured to optimize the data rate in the multiple frequency radio transmission system.

12. The apparatus of claim 11 , wherein the optimization units are configured to reduce the Block Error Rate (BLER).