nrCSIRSConfig
CSI-RS configuration parameters
Description
The nrCSIRSConfig object sets channel state information
reference signal (CSI-RS) configuration parameters for one or more zero-power (ZP) or
non-zero-power (NZP) CSI-RS resources, as defined in TS 38.211 Section 7.4.1.5 [1].
Creation
Description
csirs = nrCSIRSConfig creates a CSI-RS configuration object with
default properties.
csirs = nrCSIRSConfig( specifies
properties using one or more name-value pair arguments. Enclose each property in quotes.
For example,
Name,Value)'CSIRSType',{'zp','nzp','zp'},'Density',{'one','dot5odd','three'},'SubcarrierLocations',{0,4,[0
4]} specifies three CSI-RS resources with different frequency density values
and different frequency-domain locations. Unspecified properties take their default
values.
Properties
Examples
Generate ZP and NZP-CSI-RS Symbols and Indices
Create a carrier configuration object, specifying the slot number as 10.
carrier = nrCarrierConfig('NSlot',10);Create a CSI-RS resource configuration object for two periodic resources. Specify one NZP resource and one ZP resource with row numbers 3 and 5, symbol locations 13 and 9, and subcarrier locations 6 and 4, respectively. For both resources, set the periodicity to 5, offset to 1, and density to 'one'.
csirs = nrCSIRSConfig;
csirs.CSIRSType = {'nzp','zp'};
csirs.CSIRSPeriod = {[5 1],[5 1]};
csirs.RowNumber = [3 5];
csirs.Density = {'one','one'};
csirs.SymbolLocations = {13,9};
csirs.SubcarrierLocations = {6,4};Generate CSI-RS symbols and indices for the specified carrier, CSI-RS resource configuration, and output formatting name-value pair arguments. Verify the format of the symbols and indices.
[sym,info_sym] = nrCSIRS(carrier,csirs,... 'OutputResourceFormat','cell')
sym=1×2 cell array
{0x1 double} {0x1 double}
info_sym = struct with fields:
ResourceOrder: [2 1]
KBarLBar: {{1x1 cell} {1x2 cell}}
CDMGroupIndices: {[0] [0 1]}
KPrime: {[0 1] [0 1]}
LPrime: {[0] [0]}
[ind,info_ind] = nrCSIRSIndices(carrier,csirs,... 'IndexStyle','subscript','OutputResourceFormat','cell')
ind=1×2 cell array
{0x3 uint32} {0x3 uint32}
info_ind = struct with fields:
ResourceOrder: [2 1]
KBarLBar: {{1x1 cell} {1x2 cell}}
CDMGroupIndices: {[0] [0 1]}
KPrime: {[0 1] [0 1]}
LPrime: {[0] [0]}
Verify that the generated outputs are in the order of ZP-CSI-RS resources followed by NZP-CSI-RS resources in terms of the specified csirs.CSIRSType indices.
info_sym.ResourceOrder
ans = 1×2
2 1
info_ind.ResourceOrder
ans = 1×2
2 1
Generate and Map CSI-RS Symbols Used for Tracking
Create a carrier configuration object with default properties.
carrier = nrCarrierConfig;
Create a CSI-RS resource configuration object with CSI-RS parameters set for tracking. Specify four periodic NZP-CSI-RS resources in two consecutive slots. Specify for each slot to contain two periodic NZP-CSI-RS resources with periodicity set to 20. Set the offset for the first two resources to 0. Set the offset for the next two resources to 1. Set the row number to 1 and density to 'three' for all resources.
csirs = nrCSIRSConfig;
csirs.CSIRSType = {'nzp','nzp','nzp','nzp'};
csirs.CSIRSPeriod = {[20 0],[20 0],[20 1],[20 1]};
csirs.RowNumber = [1 1 1 1];
csirs.Density = {'three','three','three','three'};
csirs.SymbolLocations = {6,10,6,10};
csirs.SubcarrierLocations = {0,0,0,0};Generate CSI-RS symbols and indices for the default slot number of the carrier configuration object (slot number 0).
ind0 = nrCSIRSIndices(carrier,csirs); sym0 = nrCSIRS(carrier,csirs);
Map the symbols to a carrier grid of one slot duration.
gridSize = [12*carrier.NSizeGrid carrier.SymbolsPerSlot max(csirs.NumCSIRSPorts)]; slotgrid0 = complex(zeros(gridSize)); slotgrid0(ind0) = sym0;
Change the absolute slot number in the carrier configuration from 0 to 1.
carrier.NSlot = 1;
Generate CSI-RS symbols and indices for slot number 1.
ind1 = nrCSIRSIndices(carrier,csirs); sym1 = nrCSIRS(carrier,csirs);
Map the symbols to another carrier grid of one slot duration.
slotgrid1 = complex(zeros(gridSize)); slotgrid1(ind1) = sym1;
Concatenate the two slots to form the final grid.
grid = [slotgrid0 slotgrid1];
Plot the grid.
imagesc(abs(grid(:,:,1))); axis xy; title('CSI-RS as Tracking Reference Signal'); xlabel('OFDM Symbols'); ylabel('Subcarriers');
References
[1] 3GPP TS 38.211. “NR; Physical channels and modulation.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network.