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nrPUSCHDMRSIndices

Generate PUSCH DM-RS indices

Description

example

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.

example

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

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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
      ⋮

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');

Figure contains an axes object. The axes object with title PUSCH DM-RS Resource Elements in the Carrier Resource Grid contains an object of type image.

Input Arguments

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

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

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

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

RE indexing form, specified as 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

RE indexing base, specified as one of these values:

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

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

Data Types: char | string

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 the carrier grid.

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

Data Types: char | string

Output Arguments

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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 number of columns depends on the TransmissionScheme property of nrPUSCHConfig object and returned as one these values.

    • Number of transmission layers — When the transmission scheme is non-codebook

    • Number of antenna ports configured — When the transmission scheme is codebook

  • 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

Version History

Introduced in R2020a