Smaller sub-band size for PMI than for CQI
A method performed by a wireless device ( 510, 700, 1100 ) is disclosed. The wireless device obtains ( 601 ) a configuration for a sub-band channel quality indicator (CQI) granularity and a sub-band precoding matrix indicator (PMI) granularity for the wireless device. The wireless device determines ( 602 ) channel state information (CSI) feedback according to the configured sub-band CQI granularity and the sub-band PMI granularity. The sub-band PMI granularity corresponds to a first sub-band size and the sub-band CQI granularity corresponds to a second sub-band size. The first sub-band size is smaller than the second sub-band size. The wireless device transmits ( 603 ), to a network node ( 560, 1000 ), the determined CSI feedback.
1. A method performed by a wireless device for transmitting channel state information, CSI, feedback using a multi-beam precoder codebook, the method comprising:
receiving a configuration for a sub-band size for channel quality indicator, CQI, reporting and a sub-band size for precoding matrix indicator, PMI, reporting, wherein the sub-band size for PMI reporting is smaller than the sub-band size for CQI reporting; and
transmitting the CSI feedback to a base station, wherein the CSI feedback is in accordance with the sub-band size for CQI reporting and the sub-band size for PMI reporting, wherein the CSI feedback indicates a precoder vector for each of a plurality of frequency sub-bands having the sub-band size for PMI reporting, wherein each of the precoder vectors is a linear combination of vectors, and wherein the coefficients for the vectors in the linear combinations of vectors are parameterized in the frequency-domain as a linear combination of a set of basis vectors and a set of coefficients for the basis vectors in the linear combination of the set of basis vectors.
2. The method of claim 1 , wherein the vectors are discrete Fourier transform, DFT, precoder vectors.
3. The method of claim 1 , wherein the CSI feedback is transmitted using a new radio, NR, Type II multi-beam precoder codebook.
4. The method of claim 1 , wherein the CSI feedback is of new radio, NR, enhanced Type II.
5. The method of claim 1 , wherein the sub-band size for CQI reporting is an integer multiple of the sub-band size for PMI reporting.
6. The method of claim 1 , wherein the configuration for the sub-band size for CQI reporting is obtained from a subbandSize radio resource control parameter in a CSI-ReportConfig.
7. The method of claim 1 , wherein the sub-band size for PMI reporting is obtained from a CSI-ReportConfig using a subbandPMI-Size parameter.
8. A method performed by a base station for receiving channel state information, CSI, feedback using a multi-beam precoder codebook, the method comprising:
receiving the CSI feedback from a wireless device according to a sub-band size for channel quality indicator, CQI, reporting and a sub-band size for precoding matrix indicator, PMI, reporting wherein the sub-band size for PMI reporting is smaller than the sub-band size for CQI reporting, wherein the CSI feedback indicates a precoder vector for each of a plurality of frequency sub-bands having the sub-band size for PMI reporting, wherein each of the precoder vectors is a linear combination of vectors, and wherein the coefficients for the vectors in the linear combinations of vectors are parameterized in the frequency-domain as a linear combination of a set of basis vectors and a set of coefficients for the basis vectors in the linear combination of the set of basis vectors.
9. The method of claim 8 , further comprising:
determining the sub-band size for CQI reporting;
determining the sub-band size for PMI reporting; and
configuring the wireless device with the sub-band size for CQI reporting and the sub-band size for PMI reporting.
10. The method of claim 1 , wherein the vectors are discrete Fourier transform, DFT, vectors, wherein the CSI feedback is received using a new radio, NR, Type II multi-beam precoder codebook, and wherein the CSI feedback is of new radio, NR, enhanced Type II.
11. A wireless device for transmitting channel state information, CSI, feedback using a multi-beam precoder codebook, the wireless device comprising:
a receiver;
a transmitter; and
processing circuitry coupled to the receiver and the transmitter, wherein the processing circuitry is configured to cause the wireless device to:
receive a configuration for a sub-band size for channel quality indicator, CQI, reporting and a sub-band size for precoding matrix indicator, PMI, reporting, wherein the sub-band size for PMI reporting is smaller than the sub-band size for CQI reporting; and
transmit the CSI feedback to a base station, wherein the CSI feedback is in accordance with the sub-band size for CQI reporting and the sub-band size for PMI reporting, wherein the CSI feedback indicates a precoder vector for each of a plurality of, frequency sub-bands having the sub-band size for PMI reporting, wherein each of the precoder vectors is a linear combination of vectors, and wherein the coefficients for the vectors in the linear combinations of vectors are parameterized in the frequency-domain as a linear combination of a set of basis vectors and a set of coefficients for the basis vectors in the linear combination of the set of basis vectors.
12. The wireless device of claim 11 , wherein the vectors are discrete Fourier transform, DFT, precoder vectors.
13. The wireless device of claim 11 , wherein the CSI feedback is transmitted using a new radio, NR, Type II codebook.
14. The wireless device claim 11 , wherein the CSI feedback is of new radio, NR, enhanced Type II.
15. The wireless device of claim 11 , wherein the sub-band size for CQI reporting is an integer multiple of the sub-band size for PMI reporting.
16. The wireless device of claim 15 , wherein the processing circuitry is configured to cause the wireless device to obtain the configuration for the sub-band size for CQI reporting from a subbandSize radio resource control parameter in a CSI-ReportConfig.
17. The wireless device of claim 11 , wherein the processing circuitry is configured to cause the wireless device to obtain the sub-band size for PMI reporting from a CSI-ReportConfig using a subbandPMI-Size parameter.
18. A base station for receiving channel state information, CSI, feedback using a multi-beam precoder codebook, the base station comprising:
a receiver;
a transmitter; and
processing circuitry coupled to the receiver and the transmitter, wherein the processing circuitry is configured to cause the base station to:
receive the CSI feedback from a wireless device according to a sub-band size for channel quality indicator, CQI, reporting and a sub-band size for precoding matrix indicator, PMI, reporting, wherein the sub-band size for PMI reporting is smaller than the sub-band size for CQI reporting, wherein the CSI feedback indicates a precoder vector for each of a plurality of frequency sub-bands having the sub-band size for PMI reporting, wherein each of the precoder vectors is a linear combination of vectors, and wherein the coefficients for the vectors in the linear combinations of vectors are parameterized in the frequency-domain as a linear combination of a set of basis vectors and a set of coefficients for the basis vectors in the linear combination of the set of basis vectors.
19. The base station of claim 18 , wherein the processing circuitry is further configured to cause the base station to:
determine the sub-band size for CQI reporting;
determine the sub-band size for PMI reporting; and
configure the wireless device with the sub-band size for CQI reporting and the sub-band size for PMI reporting.
20. The base station of claim 18 , wherein the vectors are discrete Fourier transform, DFT, vectors, wherein the CSI feedback is received using a new radio, NR, Type II multi-beam precoder codebook, and wherein the CSI feedback is of new radio, NR, enhanced Type II.