Apparatus for CSI reporting overhead reduction via joint CSI report quantization and encoding
Techniques of generating CSI reports include designating at least one of the reports as a reference and the other reports as dependent on the reference. For example, a dependent CSI report may have a differential value of a CSI quantity rather than a raw value of the CSI quantity. Because generally for parameters in a CSI report, the differential quantity has a smaller range of values than the raw values of the CSI quantity, a quantization of the differential value of the CSI quantity will have fewer bits than the raw value; for example, for L1-RSRP, the raw value has 7 bits while the differential value has 4 bits. In another example, a dependent value of a CSI quantity is a flag indicating that the CSI quantity value is located in a reference CSI report.
1 . An apparatus, comprising:
at least one processor; and
at least one non-transitory memory storing instructions that, when executed with the at least one processor, cause the apparatus at least to:
receive a plurality of channel state information reference signals (CSI-RSs), each of the plurality of CSI-RSs being sent from a respective transmission and reception point (TRP) of a plurality of TRPs;
obtain measurements on the plurality of CSI-RSs to generate values of channel state information (CSI) quantities for a respective CSI report of a plurality of CSI reports, each CSI quantity being generated according to a respective interference hypothesis of a plurality of interference hypotheses, each of the plurality of interference hypotheses corresponding to a respective subset of the plurality of TRPs, each CSI report of the plurality of CSI reports consisting of values of all of the following CSI quantities;
channel quality indicator (CQI),
precoding matrix indicator (PMI),
CSI-RS resource indicator (CRI),
rank indicator (RI),
wide band indication (I1)
SSB resource indicator (SSBRI),
reference signal received power (L1-RSRP), and
signal to interference and noise ratio (L1-SINR);
select a subset of the plurality of CSI reports as reference CSI reports of a set of reference CSI reports;
receive configuration information via a radio resource control, the configuration information indicating that joint encoding is to be performed for a set of CSI reporting configurations that are associated with a same trigger state and have a same slot periodicity and offset, the configuration information further indicating a differential quantization mode in which the apparatus generates a plurality of dependent CSI reports,
wherein the differential quantization mode includes replacing, as a CSI quantity value, each of the following CSI quantities:
precoding matrix indicator (PMI),
CSI-RS resource indicator (CRI),
rank indicator (RI),
wide band indication (I1)
SSB resource indicator (SSBRI),
reference signal received power (L1-RSRP), and
signal to interference and noise ratio (L1-SINR),
with a respective value of a respective differential CSI quantity in a dependent CSI report of the plurality of dependent CSI reports,
wherein the value of the differential CSI quantity in the dependent CSI report is quantized to a specified number of bits, the number of bits of the quantized value of the differential CSI quantity being less than a number of bits of the value of the CSI quantity in a reference CSI report of the plurality of reference CSI reports,
wherein in each dependent CSI report, each CSI quantity of the dependent CSI report has a different respective reference CSI report;
generate, for the rest of the plurality of channels, the plurality of dependent CSI reports, each of the plurality of dependent CSI reports replacing a value of the CSI quantity with a secondary value of the CSI quantity, the secondary value of the CSI quantity included in that dependent CSI report, in combination with the value of the CSI quantity included in a reference CSI of the set of reference CSI reports, producing the value of the CSI quantity of the channel of the plurality of channels; and
transmit the set of reference CSI reports and the plurality of dependent CSI reports to the plurality of transmission and reception points.