Three-Component Codebook Based CSI Reporting

A method performed by a user equipment (UE) for providing channel state information (CSI) feedback in the form of one or more CSI reports in a wireless communication system (A), the method comprising:

• receiving, from a network node (gNB) higher layer configuration(s) of one or more downlink reference signals, and one or more CSI report configuration(s) associated with the downlink reference signal configuration(s), and a radio signal, the radio signal including the downlink reference signal(s) according to the one or more downlink reference signal configuration(s),
• the downlink reference signal(s) being provided over a configured number of frequency domain resources, time domain resources and one or more ports;
• determining, for each CSI report, a precoding matrix based on the downlink reference signal(s) and two codebooks, the two codebooks including
• a spatial codebook comprising one or more spatial domain (SD) basis components of the precoder, and
• a delay codebook comprising one or more delay domain (DD) basis components of the precoder,
• and one or more non-zero combining coefficients for complex combining of the one or more SD and DD basis vectors;
• and
• reporting, to the network node, the one or more CSI reports for the one or more CSI report configurations,
• wherein each CSI report contains the selected precoding matrix in the form of a precoding matrix identifier (PMI) and a rank identifier (RI) indicating the transmission rank for the RI layers of the precoding matrix, and wherein each CSI report comprises two parts:
• CSI part 1 and CSI part 2, wherein part 1 has a fixed payload size and comprises information indicating the size of the payload of part 2, wherein part 2 comprises at least the amplitude and phase information of the selected non-zero combining coefficients of the CSI report, and wherein a portion, or the entirety, of part 2 is available for omission from the CSI report.

A method performed by a network node (gNB) for receiving channel state information (CSI) feedback in the form of one or more CSI reports in a wireless communication system (A), the method comprising:

• sending, to a user equipment (UE) higher layer configuration(s) of one or more downlink reference signals, and one or more CSI report configuration(s) associated with the downlink reference signal configuration(s), and a radio signal, the radio signal including the downlink reference signal(s) according to the one or more downlink reference signal configuration(s);
• and
• receiving, from the UE one or more CSI reports for one or more CSI report configurations,
• wherein each CSI reports comprises:
• a precoding matrix determined based on the downlink reference signal(s) and two codebooks, the two codebooks including:
• a spatial codebook comprising one or more spatial domain (SD) basis components of the precoder, and
• a delay codebook comprising one or more delay domain (DD) basis components of the precoder,
• and one or more non-zero combining coefficients for complex combining of the one or more SD and DD basis vectors,
• wherein each CSI report contains the selected precoding matrix in the form of a precoding matrix identifier (PMI) and a rank identifier (RI) indicating the transmission rank for the RI layers of the precoding matrix, and wherein each CSI report comprises two parts:
• CSI part 1 and CSI part 2, wherein part 1 has a fixed payload size and comprises information indicating the size of the payload of part 2, wherein part 2 comprises at least the amplitude and phase information of the selected non-zero combining coefficients of the CSI report, and wherein a portion, or the entirety, of part 2 is available for omission from the CSI report.

A user equipment (UE) comprising a processor and a memory, the memory containing computer program code executable by the processor whereby the UE is operative to:

• receive, from a network node (gNB) higher layer configuration(s) of one or more downlink reference signals, and one or more CSI report configuration(s) associated with the downlink reference signal configuration(s), and a radio signal, the radio signal including the downlink reference signal(s) according to the one or more downlink reference signal configuration(s),
• the downlink reference signal(s) being provided over a configured number of frequency domain resources, time domain resources and one or more ports;
• determine, for each CSI report, a precoding matrix based on the downlink reference signal(s) and two codebooks, the two codebooks including
• a spatial codebook comprising one or more spatial domain (SD) basis components of the precoder, and
• a delay codebook comprising one or more delay domain (DD) basis components of the precoder,
• and one or more non-zero combining coefficients for complex combining of the one or more SD and DD basis vectors;
• and
• report, to the network node, the one or more CSI reports for the one or more CSI report configurations,
• wherein each CSI report contains the selected precoding matrix in the form of a precoding matrix identifier (PMI) and a rank identifier (RI) indicating the transmission rank for the RI layers of the precoding matrix, and wherein each CSI report comprises two parts:
• CSI part 1 and CSI part 2, wherein part 1 has a fixed payload size and comprises information indicating the size of the payload of part 2, wherein part 2 comprises at least the amplitude and phase information of the selected non-zero combining coefficients of the CSI report, and wherein a portion, or the entirety, of part 2 is available for omission from the CSI report.

A network node comprising a processor and a memory, the memory containing computer program code executable by the processor whereby the network node is operative to:

• send, to a user equipment (UE) higher layer configuration(s) of one or more downlink reference signals, and one or more CSI report configuration(s) associated with the downlink reference signal configuration(s), and a radio signal, the radio signal including the downlink reference signal(s) according to the one or more downlink reference signal configuration(s);
• and
• receive, from the UE one or more CSI reports for one or more CSI report configurations, wherein each CSI reports comprises:
• a precoding matrix determined based on the downlink reference signal(s) and two codebooks, the two codebooks including:
• a spatial codebook comprising one or more spatial domain (SD) basis components of the precoder, and
• a delay codebook comprising one or more delay domain (DD) basis components of the precoder,
• and one or more non-zero combining coefficients for complex combining of the one or more SD and DD basis vectors,
• wherein each CSI report contains the selected precoding matrix in the form of a precoding matrix identifier (PMI) and a rank identifier (RI) indicating the transmission rank for the RI layers of the precoding matrix, and wherein each CSI report comprises two parts:
• CSI part 1 and CSI part 2, wherein part 1 has a fixed payload size and comprises information indicating the size of the payload of part 2, wherein part 2 comprises at least the amplitude and phase information of the selected non-zero combining coefficients of the CSI report, and wherein a portion, or the entirety, of part 2 is available for omission from the CSI report.

A computer program product comprising computer program code, which, when executed by a processor of a user equipment (UE) enables the processor to:

• receive, from a network node (gNB) higher layer configuration(s) of one or more downlink reference signals, and one or more CSI report configuration(s) associated with the downlink reference signal configuration(s), and a radio signal, the radio signal including the downlink reference signal(s) according to the one or more downlink reference signal configuration(s),
• the downlink reference signal(s) being provided over a configured number of frequency domain resources, time domain resources and one or more ports;
• determine, for each CSI report, a precoding matrix based on the downlink reference signal(s) and two codebooks, the two codebooks including
• a spatial codebook comprising one or more spatial domain (SD) basis components of the precoder, and
• a delay codebook comprising one or more delay domain (DD) basis components of the precoder,
• and one or more non-zero combining coefficients for complex combining of the one or more SD and DD basis vectors;
• and
• report, to the network node, the one or more CSI reports for the one or more CSI report configurations,
• wherein each CSI report contains the selected precoding matrix in the form of a precoding matrix identifier (PMI) and a rank identifier (RI) indicating the transmission rank for the RI layers of the precoding matrix, and wherein each CSI report comprises two parts:
• CSI part 1 and CSI part 2, wherein part 1 has a fixed payload size and comprises information indicating the size of the payload of part 2, wherein part 2 comprises at least the amplitude and phase information of the selected non-zero combining coefficients of the CSI report, and wherein a portion, or the entirety, of part 2 is available for omission from the CSI report.

A computer program product comprising computer program code, which, when executed by a processor of a network node (gNB) enables the processor to:

• send, to a user equipment (UE) higher layer configuration(s) of one or more downlink reference signals, and one or more CSI report configuration(s) associated with the downlink reference signal configuration(s), and a radio signal, the radio signal including the downlink reference signal(s) according to the one or more downlink reference signal configuration(s);
• and
• receive, from the UE one or more CSI reports for one or more CSI report configurations, wherein each CSI reports comprises:
• a precoding matrix determined based on the downlink reference signal(s) and two codebooks, the two codebooks including:
• a spatial codebook comprising one or more spatial domain (SD) basis components of the precoder, and
• a delay codebook comprising one or more delay domain (DD) basis components of the precoder,
• and one or more non-zero combining coefficients for complex combining of the one or more SD and DD basis vectors,
• wherein each CSI report contains the selected precoding matrix in the form of a precoding matrix identifier (PMI) and a rank identifier (RI) indicating the transmission rank for the RI layers of the precoding matrix, and wherein each CSI report comprises two parts:
• CSI part 1 and CSI part 2, wherein part 1 has a fixed payload size and comprises information indicating the size of the payload of part 2, wherein part 2 comprises at least the amplitude and phase information of the selected non-zero combining coefficients of the CSI report, and wherein a portion, or the entirety, of part 2 is available for omission from the CSI report.