nrPUSCHDMRSIndices

Generate PUSCH DM-RS indices

Syntax

ind = nrPUSCHDMRSIndices(carrier,pusch)

ind = nrPUSCHDMRSIndices(carrier,pusch,Name,Value)

Description

ind = nrPUSCHDMRSIndices(carrier,pusch) returns a matrix containing demodulation reference signal (DM-RS) resource element (RE) indices of a physical uplink shared channel (PUSCH), as defined in TS 38.211 Section 6.4.1.1.3 [1]. carrier specifies the carrier configuration parameters for a specific OFDM numerology. pusch specifies the PUSCH configuration parameters. The returned indices are 1-based using linear indexing form.

ind = nrPUSCHDMRSIndices(carrier,pusch,Name,Value) specifies output formatting options by using one or more name-value pair arguments. Unspecified options take default values.

Examples

Generate PUSCH DM-RS Indices for Codebook-Based Transmission

Create a carrier configuration object with default properties. This object corresponds to a 10 MHz carrier with 15 kHz subcarrier spacing.

carrier = nrCarrierConfig;

Create a physical uplink shared channel (PUSCH) configuration object with specified properties. When transform precoding is set to 0, the waveform type is cyclic-prefix orthogonal frequency division multiplexing (CP-OFDM).

pusch = nrPUSCHConfig;
pusch.TransformPrecoding = 0;
pusch.TransmissionScheme = 'codebook';
pusch.NumAntennaPorts = 4;
pusch.TPMI = 0;

Configure PUSCH demodulation reference signal (DM-RS) object with specified parameters.

pusch.DMRS.DMRSAdditionalPosition = 2;
pusch.DMRS.DMRSTypeAPosition = 2;
pusch.DMRS.DMRSPortSet = 3;
pusch.DMRS.NIDNSCID = 15;
pusch.DMRS.NSCID = 1;

Generate DM-RS indices associated to PUSCH of subscript indexing form.

ind = nrPUSCHDMRSIndices(carrier,pusch,'IndexStyle','subscript')

ind = 3744x3 uint32 matrix

    2    3    1
    4    3    1
    6    3    1
    8    3    1
   10    3    1
   12    3    1
   14    3    1
   16    3    1
   18    3    1
   20    3    1
      ⋮

Generate PUSCH DM-RS Symbols and Indices

Create a carrier configuration with 30 kHz subcarrier spacing and 5 MHz transmission bandwidth.

carrier = nrCarrierConfig;
carrier.SubcarrierSpacing = 30;
carrier.NSizeGrid = 11;

Create a physical uplink shared channel (PUSCH) configuration object with specified properties. When transform precoding is set to 1, the waveform type is discrete fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM).

pusch = nrPUSCHConfig;
pusch.NSizeBWP = 9;
pusch.NStartBWP = 1;
pusch.PRBSet = 0:3;
pusch.TransformPrecoding = 1;
pusch.FrequencyHopping = 'intraSlot';
pusch.SecondHopStartPRB = 5;

Create a PUSCH demodulation reference signal (DM-RS) object with specified properties.

dmrs = nrPUSCHDMRSConfig;
dmrs.DMRSAdditionalPosition = 1;
dmrs.DMRSTypeAPosition = 2;
dmrs.DMRSPortSet = 3;
dmrs.GroupHopping = 1;
dmrs.SequenceHopping = 0;
dmrs.NRSID = 10;

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

pusch.DMRS = dmrs;

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

sym = nrPUSCHDMRS(carrier,pusch,'OutputDataType','single')

sym = 96x1 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 = nrPUSCHDMRSIndices(carrier,pusch,'IndexBase','0based','IndexOrientation','bwp')

ind = 96x1 uint32 column vector

   217
   219
   221
   223
   225
   227
   229
   231
   233
   235
      ⋮

Create a bandwidth part (BWP) grid, and then map the DM-RS symbols on the grid.

bwp = complex(zeros([pusch.NSizeBWP*12 carrier.SymbolsPerSlot pusch.NumLayers]));
bwp(ind+1) = sym; % Map the DM-RS symbols

Map the BWP to the carrier resource grid, and then display the carrier grid.

grid = complex(zeros([carrier.NSizeGrid*12 carrier.SymbolsPerSlot pusch.NumLayers])); % Create carrier resource grid
offset = pusch.NStartBWP-carrier.NStartGrid; % BWP start location in the carrier grid
grid(offset*12+1:(offset+pusch.NSizeBWP)*12,:,:) = bwp;
imagesc(abs(grid(:,:,1)));
axis xy;
xlabel('OFDM Symbols');
ylabel('Subcarriers');
title('PUSCH 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.

Property Field	Values	Description
SubcarrierSpacing	15 (default), 30, 60, 120, 240	Subcarrier spacing in kHz
CyclicPrefix	'normal' (default), 'extended'	Cyclic prefix length, specified as one of these options. 'normal' corresponds to 14 OFDM symbols in a slot. 'extended' corresponds to 12 OFDM symbols in a slot. For the numerologies specified in TS 38.211 Section 4.2, extended cyclic prefix length applies only for 60 kHz subcarrier spacing.
NSizeGrid	52 (default), integer from 1 to 275	Number of resource blocks in the carrier resource grid
NStartGrid	0 (default), integer from 0 to 2199	Start of carrier resource grid relative to common resource block 0 (CRB 0)
NSlot	0 (default), nonnegative integer scalar	Slot number. You can set NSlot to a value larger than the number of slots per frame.

pusch — PUSCH configuration parameters

nrPUSCHConfig object

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

Property Field	Values	Description
NSizeBWP	[] (default), integer from 1 to 275	Size of the bandwidth part (BWP) in terms of number of physical resource blocks (PRBs). The default value of [] implies that the value is equal to NSizeGrid of carrier input argument.
NStartBWP	[] (default), integer from 0 to 2473	Starting PRB index of BWP relative to CRB 0. The default value of [] implies that the value is equal to NStartGrid of carrier input argument.
NumLayers	1 (default), integer from 1 to 4	Number of transmission layers
MappingType	'A' (default), 'B'	Mapping type of PUSCH
SymbolAllocation	[0 14] (default), two-element vector of nonnegative integers	OFDM symbols allocated for PUSCH
PRBSet	[0:51] (default), vector of nonnegative integers from 0 to 274	PRBs allocated for PUSCH within the BWP
TransformPrecoding	0 (default), 1	Transform precoding flag, specified as one of these values. 0 indicates that the transform precoding is enabled and waveform type is CP-OFDM. 1 indicates that the transform precoding is disabled and waveform type is DFT-s-OFDM.
TransmissionScheme	'nonCodebook' (default), 'codebook'	PUSCH transmission scheme
NumAntennaPorts	1 (default), 2, or 4	Number of antenna ports. The value must be greater than or equal to NumLayers. This property is applicable when TransmissionScheme is set to 'codebook'.
FrequencyHopping	'neither (default), 'intraSlot', or 'interSlot'	Frequency hopping configuration for PUSCH
SecondHopStartPRB	1 (default), integer from 0 to 274	Starting PRB index of second hop relative to BWP
DMRS	nrPUSCHDMRSConfig configuration object	DMRS configuration object only uses these properties. DMRSConfigurationType DMRSTypeAPosition DMRSLength DMRSAdditionalPosition CustomSymbolSet DMRSPortSet For more information, see nrPUSCHDMRSConfig.

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: 'IndexStyle','subscript','IndexBase','0based' specifies nondefault resource element index formatting properties.

'IndexStyle' — Resource element indexing form

'index' (default) | 'subscript'

Resource element indexing form, specified as the comma-separated pair consisting of 'IndexStyle' and one of these values:

• 'index' — The indices are in linear index form.

• 'subscript' — The indices are in [subcarrier, symbol, antenna] subscript row form.

Data Types: char | string

'IndexBase' — Resource element indexing base

'1based' (default) | '0based'

Resource element indexing base, specified as the comma-separated pair consisting of 'IndexBase' and one of these values:

• '1based' — The index counting starts from one.

• '0based' — The index counting starts from zero.

Data Types: char | string

'IndexOrientation' — Indexing orientation of resource elements

'carrier' (default) | 'bwp'

Indexing orientation of resource elements, specified as the comma-separated pair consisting of 'IndexOrientation' and one of these values:

• 'carrier' — Indices are referenced with respect to carrier grid.

• 'bwp' — Indices are referenced with respect to bandwidth part.

Data Types: char | string

Output Arguments

ind — DM-RS resource element indices

N-by-P matrix | M-by-3 matrix

DM-RS resource element indices, returned as one of these values:

• N-by-P matrix — The function returns this type of value when 'IndexStyle' is set to 'index'. The matrix columns correspond to the antenna ports configured.

• M-by-3 matrix — The function returns this type of value when 'IndexStyle' is set to 'subscript'. The matrix rows correspond to the [subcarrier, symbol, antenna] subscripts based on the number of subcarriers, OFDM symbols, and number of antennas, respectively.

Depending on the value of 'IndexBase', the function returns either 1-based or 0-based indices. Depending on the value of 'IndexOrientation', the function returns either carrier oriented indices or BWP oriented indices.

Data Types: uint32

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:

Names and values in name-value pair arguments must be compile-time constants. For example, to specify linear indexing form, include {coder.Constant('IndexStyle'),coder.Constant('index')} in the -args value of the codegen function. For more information, see the coder.Constant (MATLAB Coder) class.