Method, apparatus and communication unit
View Patent ↗A method, an apparatus and a communication unit for generating precoding feedback information in a multiple frequency radio transmission system are disclosed. A rank for precoding matrices, wherein the rank is constant over the multiple frequencies, is selected and a plurality of precoding matrices having the selected rank are selected. A different precoding matrix is selected for each frequency subset of the multiple frequencies.
1. A method, comprising:
determining a rank for a set of sub-bands;
generating a rank feedback regarding the rank;
selecting a sub-band precoding matrix for a sub-band from the set of the sub-bands;
generating a sub-band precoding matrix index regarding the sub-band precoding matrix based on the rank that is determined for the set of sub-bands; and
decoding a data stream to be transmitted based on the sub-band precoding matrix.
2. The method of claim 1 , wherein the sub-band precoding matrix is selected according to 3GPP-LTE standard.
3. The method of claim 1 , wherein selecting the sub-band precoding matrix comprises selecting the sub-band precoding matrix from a precoding codebook for the selected sub-band.
4. The method of claim 1 , wherein the rank is constant over the set of the sub-bands.
5. The method of claim 1 , wherein selecting the sub-band precoding matrix comprises selecting the sub-band precoding matrix to maximize a data rate of the data stream.
6. The method of claim 1 , further comprising:
selecting a wideband precoding matrix for the set of sub-bands from a precoding codebook for the set of sub-bands.
7. The method of claim 6 , wherein the wideband precoding matrix is based on a maximum likelihood estimate of a transmit correlation matrix.
8. The method of claim 6 , further comprising:
generating a wideband precoding matrix index of the selected wideband precoding matrix.
9. The method of claim 6 , wherein the wideband precoding matrix is constant over the set of sub-bands.
10. An apparatus, comprising:
a circuit comprising an output, wherein the circuit is configured to:
provide a feedback for a rank over a set of sub-bands;
provide a wideband precoding matrix index for a wideband precoding matrix from a codebook for the set of sub-bands based on the rank of the set of sub-bands;
provide a sub-band precoding matrix index for a sub-band precoding matrix from the codebook for a sub-band from the set of the sub-bands, and wherein the sub-band precoding matrix index is generated based on the rank of the set of sub-bands; and
decode a data stream to be transmitted based on the sub-band precoding matrix.
11. The apparatus of claim 10 , wherein the wideband precoding matrix is constant over the set of sub-bands.
12. The apparatus of claim 10 , wherein the apparatus is in a baseband chip of a mobile phone, a handheld device, a receiver, a base station, or a transmitter.
13. The apparatus of claim 10 , wherein the apparatus is outside a baseband chip of a mobile phone, a handheld device, a receiver, a base station, or a transmitter.
14. The apparatus of claim 10 , wherein the circuit is further configured to select the wideband precoding matrix to maximize a data rate in transmission.
15. A mobile phone, comprising:
at least one antenna;
a transmitter coupled to the at least one antenna, wherein the transmitter is configured to:
provide a rank corresponding to a set of sub-bands and a feedback on the rank;
provide a wideband precoding matrix index of a wideband precoding matrix corresponding to the set of sub-bands and the rank of the set of sub-bands, wherein the wideband precoding matrix is based on a maximum likelihood estimate of a transmit correlation matrix; and
provide a sub-band precoding matrix index of a sub-band precoding matrix for a sub-band from the set of the sub-bands, and wherein the sub-band precoding matrix is generated corresponding to the rank of the set of sub-bands.
16. The mobile phone of claim 15 , wherein the sub-band precoding matrix is used to precode a transmission signal to be transmitted by the mobile phone.
17. The mobile phone of claim 16 , wherein the transmission signal is to be received by a receiver comprising a linear minimum mean square error (MMSE) equalizer.