nrPDSCHDMRS

Generate PDSCH DM-RS symbols

Since R2020a

Syntax

sym = nrPDSCHDMRS(carrier,pdsch)

sym = nrPDSCHDMRS(carrier,pdsch,'OutputDataType',datatype)

Description

sym = nrPDSCHDMRS(carrier,pdsch) returns a matrix containing demodulation reference signal (DM-RS) symbols of physical downlink shared channel (PDSCH), as defined in TS 38.211 Section 7.4.1.1.1 [1]. carrier specifies the carrier configuration parameters for a specific OFDM numerology. pdsch specifies the PDSCH configuration parameters.

sym = nrPDSCHDMRS(carrier,pdsch,'OutputDataType',datatype) specifies the data type for the DM-RS symbols.

Examples

Generate PDSCH DM-RS Symbols and Indices

Create a carrier configuration object specifying the slot number as 10.

carrier = nrCarrierConfig('NSlot',10);

Create a physical downlink shared channel (PDSCH) configuration object, pdsch, with physical resource blocks (PRBs) allocated from 0 to 30.

pdsch = nrPDSCHConfig;
pdsch.PRBSet = 0:30;

Create a PDSCH demodulation reference signal (DM-RS) object, dmrs, with specified properties.

dmrs = nrPDSCHDMRSConfig;
dmrs.DMRSConfigurationType = 2;
dmrs.DMRSLength = 2;
dmrs.DMRSAdditionalPosition = 1;
dmrs.DMRSTypeAPosition = 2;
dmrs.DMRSPortSet = 5;
dmrs.NIDNSCID = 10;
dmrs.NSCID = 0;

Assign the PDSCH DM-RS configuration object to DMRS property of PDSCH configuration object.

pdsch.DMRS = dmrs;

Generate PDSCH DM-RS symbols and indices for the specified carrier, PDSCH configuration, and output formatting name-value pair argument.

sym = nrPDSCHDMRS(carrier,pdsch,'OutputDataType','single')

sym = 496x1 single column vector

  -0.7071 - 0.7071i
  -0.7071 + 0.7071i
  -0.7071 + 0.7071i
   0.7071 + 0.7071i
   0.7071 + 0.7071i
  -0.7071 - 0.7071i
   0.7071 - 0.7071i
  -0.7071 + 0.7071i
   0.7071 - 0.7071i
  -0.7071 - 0.7071i
      ⋮

ind = nrPDSCHDMRSIndices(carrier,pdsch,'IndexBase','0based','IndexOrientation','carrier')

ind = 496x1 uint32 column vector

   1252
   1253
   1258
   1259
   1264
   1265
   1270
   1271
   1276
   1277
      ⋮

Display the generated DM-RS symbols on the carrier resource grid.

grid = complex(zeros([carrier.NSizeGrid*12 carrier.SymbolsPerSlot pdsch.NumLayers]));
grid(ind+1) = sym;
imagesc(abs(grid(:,:,1)));
axis xy;
xlabel('OFDM Symbols');
ylabel('Subcarriers');
title('PDSCH DM-RS Resource Elements in the Carrier Resource Grid');

Input Arguments

carrier — Carrier configuration parameters

nrCarrierConfig object

Carrier configuration parameters for a specific OFDM numerology, specified as an nrCarrierConfig object. This function uses only these properties of the nrCarrierConfig object.

• NCellID

• SubcarrierSpacing

• CyclicPrefix

• NSizeGrid

• NStartGrid

• NSlot

pdsch — PDSCH configuration parameters

nrPDSCHConfig object

PDSCH configuration parameters, specified as an nrPDSCHConfig object. This function uses only these properties of the nrPDSCHConfig object.

• NSizeBWP

• NStartBWP

• ReservedPRB

• NumLayers

• MappingType

• SymbolAllocation

• PRBSet

• RNTI

• DMRS

datatype — Data type for generated DM-RS symbols

'double' (default) | 'single'

Data type for the generated DM-RS symbols, specified as 'double' or 'single'.

Data Types: char | string

Output Arguments

sym — DM-RS symbols

complex matrix

DM-RS symbols, returned as a complex matrix. The number of columns correspond to the number of antenna ports configured.

Data Types: single | double
Complex Number Support: Yes

References

[1] 3GPP TS 38.211. “NR; Physical channels and modulation.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

The datatype input argument must be compile-time constant. For example, when specifying 'single' as the output data type, include {coder.Constant('OutputDataType'),coder.Constant('single')} in the -args value of the codegen function. For more information, see the coder.Constant (MATLAB Coder) class.

Version History

Introduced in R2020a