Channel state information (CSI) processing for PDSCH and DMRS based CSI
This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for transmitting a channel state information (CSI) report from a user equipment (UE). The CSI report may be a UE initiated CSI report or may be based on a downlink grant. The UE may determine to transmit the CSI report based on measurement using a physical downlink control channel (PDSCH) and/or a demodulation reference signal (DMRS). The UE may determine a reference resource for CSI feedback. The UE may calculate a channel quality indicator (CQI) based on the reference resource. The UE may transmit the CQI in the CSI report on an uplink resource.
1 . A method of wireless communication performed by a user equipment (UE), the method comprising:
determining to transmit a channel state information (CSI) report based on measurement using at least one of a physical downlink control channel (PDSCH) or a demodulation reference signal (DMRS);
determining a reference resource for CSI feedback;
calculating a channel quality indicator (CQI) based on the reference resource; and
transmitting the CQI in the CSI report on an uplink resource, wherein the uplink resource is separated from a last symbol of the reference resource by at least a number of symbols defined by a CSI timeline, wherein the CSI timeline is determined based at least in part on a number of CSI processing unit (CPU) occupation or a number of a DMRS port.
2 . The method of claim 1 , wherein the reference resource is a slot on which the PDSCH or the DMRS is received.
3 . The method of claim 1 , wherein calculating the CQI based on the reference resource includes determining an overhead assumption for calculation of the CQI based on a slot on which the PDSCH and the DMRS are received.
4 . The method of claim 3 , wherein the overhead assumption comprises at least a number of symbols for control signaling, a number of DMRS symbols and PDSCH symbols, a number of additional DMRS symbols, and resources allocated for non-zero power (NZP) CSI reference signal (NZP-CSI-RS) and zero power (ZP) CSI-RS.
5 . The method of claim 1 , wherein calculating the CQI based on the reference resource includes determining that a CSI reporting band is equal to a frequency domain allocation of the PDSCH and the DMRS.
6 . The method of claim 5 , wherein the CSI report includes a wideband CSI.
7 . The method of claim 1 , wherein the CSI report includes a resource block group (RBG)-level CQI or physical resource group (PRG)-level CQI, wherein the RBG-level CQI or the PRG-level CQI includes the same resources as the DMRS and the PDSCH used for channel measurement or interference measurement.
8 . The method of claim 1 , wherein the CSI report includes an RBG-level CQI or an PRG-level CQI separately configured in a CSI report setting.
9 . The method of claim 1 , wherein a CSI processing unit (CPU) occupation time starts from a first symbol of an earliest one of the DMRS or the PDSCH used for channel measurement or interference measurement and ends at a last symbol of the uplink resource.
10 . The method of claim 1 , wherein a DMRS port for the DMRS and the PDSCH is active from a first symbol of the DMRS or the PDSCH used for channel measurement or interference measurement to a last symbol of the uplink resource.
11 . The method of claim 1 , wherein the uplink resource is separated from the last symbol of the reference resource by a greater of the number of symbols defined by the CSI timeline or a number of symbols defined by a hybrid automatic repeat request (HARQ) timeline when the CSI report is transmitted on a same slot as a HARQ ACK/NACK or in a same PUCCH as the HARQ ACK/NACK.
12 . The method of claim 1 , wherein determining to transmit the CSI report comprises:
determining a priority of the CSI report, wherein the priority of the CSI report is based at least in part on a type of a downlink measurement resource, whether the CSI report is triggered by the UE in response to a CSI measurement, or whether an aperiodic CSI is transmitted on a PUCCH; and
determining resource CSI multiplexing order, dropping order, or omission order based on the priority.
13 . The method of claim 12 , wherein determining the priority of the CSI report comprises determining a priority function, wherein a value of a factor in the priority function is defined by the type of the downlink measurement resource for the CSI report.
14 . The method of claim 12 , wherein determining the priority of the CSI report comprises determining a priority function, wherein a value of a factor in the priority function is defined by a trigger type of the CSI report.
15 . A method of wireless communication performed by a base station, the method comprising:
configuring a user equipment (UE) with a channel state information (CSI) report configuration including a downlink measurement resource including a physical downlink shared channel (PDSCH) or a demodulation reference signal (DMRS);
transmitting a downlink grant that schedules the PDSCH and the DMRS in a slot;
transmitting the PDSCH and the DMRS in the slot; and
receiving a CSI report including a channel quality indicator (CQI) based on the PDSCH or the DMRS from the UE on an uplink resource, wherein the uplink resource is separated from a last symbol of the PDSCH or the DMRS used for channel measurement or interference measurement by at least a number of symbols defined by a CSI timeline, wherein the CSI timeline is selected based at least in part on a number of CPU occupation or a number of a DMRS port.
16 . The method of claim 15 , wherein the CQI is based on an overhead assumption for the slot where the PDSCH and the DMRS are transmitted.
17 . The method of claim 16 , wherein the overhead assumption comprises at least a number of symbols for control signaling, a number of DMRS symbols and PDSCH symbols, a number of additional DMRS symbols, and resources allocated for non-zero power (NZP) CSI reference signal (NZP-CSI-RS) and zero power (ZP) CSI-RS.
18 . The method of claim 15 , wherein a CSI reporting band is equal to a frequency domain allocation of the PDSCH and the DMRS.
19 . The method of claim 18 , wherein the CSI report includes a wideband CSI.
20 . The method of claim 15 , wherein the CSI report includes a resource block group (RBG)-level CQI or a physical resource group (PRG)-level CQI, wherein the RBG-level CQI or the PRG-level CQI includes the same resources as the DMRS and the PDSCH used for channel measurement or interference measurement.
21 . The method of claim 15 , wherein the CSI report includes an RBG-level CQI or an PRG-level CQI separately configured in a CSI report setting.
22 . The method of claim 15 , wherein a CSI processing unit (CPU) occupation time starts from a first symbol of an earliest one of the DMRS or the PDSCH used for channel measurement or interference measurement and ends at a last symbol of the uplink resource.
23 . The method of claim 15 , wherein a DMRS port for the DMRS and the PDSCH is active from a first symbol of the DMRS or the PDSCH used for channel measurement or interference measurement to a last symbol of the uplink resource.
24 . The method of claim 15 , wherein the uplink resource is separated from a last symbol of the PDSCH or the DMRS used for channel measurement or interference measurement by a greater of the number of symbols defined by the CSI timeline or a number of symbols defined by a hybrid automatic repeat request (HARQ) timeline when the CSI report is transmitted on a same slot as a HARQ ACK/NACK or in a same PUCCH as the HARQ ACK/NACK.
25 . An apparatus for wireless communication, comprising:
a memory; and
one or more processors configured to cause the apparatus to:
determine to transmit a channel state information (CSI) report based on measurement using at least one of a physical downlink control channel (PDSCH) or a demodulation reference signal (DMRS);
determine a reference resource for CSI feedback, wherein the reference resource is a slot on which the PDSCH or the DMRS is received;
calculate a channel quality indicator (CQI) based on the reference resource; and
transmit the CQI in the CSI report on an uplink resource, wherein the uplink resource is separated from a last symbol of the reference resource by at least a number of symbols defined by a CSI timeline, wherein the CSI timeline is determined based at least in part on a number of CPU occupation or a number of a DMRS port.
26 . An apparatus for wireless communication, comprising:
a memory; and
one or more processors configured to cause the apparatus to:
configure a user equipment (UE) with a channel state information (CSI) report configuration including a downlink measurement resource including a physical downlink shared channel (PDSCH) or a demodulation reference signal (DMRS);
transmit a downlink grant that schedules the PDSCH and the DMRS in a slot;
transmit the PDSCH and the DMRS in the slot; and
receive a CSI report including a channel quality indicator (CQI) based on the PDSCH or the DMRS from the UE on an uplink resource, wherein the uplink resource is separated from a last symbol of the PDSCH or the DMRS used for channel measurement or interference measurement by at least a number of symbols defined by a CSI timeline, wherein the CSI timeline is selected based at least in part on a number of CPU occupation or a number of a DMRS port.