Add 5G NR CSI-RS to DL-SCH and PDSCH modulation

Hi,

I was re-elaborating this example https://it.mathworks.com/help/5g/ug/nr-pdsch-throughput.html#d123e1973 removing the SS burst and adding CSI data to the 5G NR grid

What've done is to configure the CSI-RS with zero power (so it would be easier to see on the trasmission grid before the channel

csirs = nrCSIRSConfig;

csirs.CSIRSType = {'zp'};

Now, the issue is that, when I use the function

ind = nrCSIRSIndices(carrier,csirs,'OutputResourceFormat','cell');

sym = nrCSIRS(carrier,csirs,'OutputResourceFormat','cell');

To have CSI-RS symbols and indices, the indices that the function returns are already used by the PDSCH modulation so, I can't understand how to add the CSI-RS and make everything work together

Answer 1

[Marc]

You need to use the ReservedREs field for the PDSCH configuration to tell the PDSCH not to use those REs.

Something like:

csirsInd = nrCSIRSIndices(carrier,csirs);

% Indicate that those REs are not available for PDSCH symbols

pdsch.ReservedREs = csirsInd-1;

Then you can generate the PDSCH indices and symbols once the ReservedREs field has been populated.