nrCSIRSIndices
Generate CSI-RS resource element indices
Syntax
Description
[
returns resource element indices ind,info] = nrCSIRSIndices(carrier,csirs)ind for the channel state information
reference signal (CSI-RS), as defined in TS 38.211 Section 7.4.1.5.3 [1]. The input
carrier specifies carrier configuration parameters for a specific
OFDM numerology. The input csirs specifies CSI-RS resource
configuration parameters for one or more zero-power (ZP) or non-zero-power (NZP) CSI-RS
resources. When configuring both ZP and NZP resources, the returned indices are in the order
ZP followed by NZP, irrespective of the resource order specified by
csirs.
The
function also returns the structure info, which contains additional
information about the CSI-RS locations.
[
specifies output formatting options by using one or more name-value pair arguments.
Unspecified options take default values.ind,info] = nrCSIRSIndices(carrier,csirs,Name,Value)
Examples
Create a carrier configuration object with default properties. This object corresponds to a 10 MHz carrier.
carrier = nrCarrierConfig;
Create a CSI-RS configuration object with default properties.
csirs = nrCSIRSConfig;
Generate CSI-RS symbols of single data type.
[sym,info_sym] = nrCSIRS(carrier,csirs,'OutputDataType','single');
Generate resource element indices for CSI-RS.
[ind,info_ind] = nrCSIRSIndices(carrier,csirs);
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
{0×1 double} {0×1 double}
info_sym = struct with fields:
ResourceOrder: [2 1]
KBarLBar: {{1×1 cell} {1×2 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
{0×3 uint32} {0×3 uint32}
info_ind = struct with fields:
ResourceOrder: [2 1]
KBarLBar: {{1×1 cell} {1×2 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
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');
Input Arguments
Name-Value Arguments
Output Arguments
References
[1] 3GPP TS 38.211. “NR; Physical channels and modulation.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network.
