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Generate PDSCH PT-RS Indices

Since R2020a



ind = nrPDSCHPTRSIndices(carrier,pdsch) returns ind, which contains 1-based phase tracking reference signal (PT-RS) resource elements (RE) of the physical downlink shared channel (PDSCH), as defined in TS 38.211 Section [1]. The function returns ind in linear form, for given carrier configuration carrier and physical downlink shared channel configuration pdsch.

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


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Create a carrier configuration object with default properties. This object corresponds to a 10 MHz carrier.

carrier = nrCarrierConfig;

Create a default PDSCH configuration object, and then enable the PT-RS configuration.

pdsch = nrPDSCHConfig;
pdsch.EnablePTRS = 1;

Create a PDSCH phase tracking reference signal (PT-RS) configuration object with specified properties.

ptrs = nrPDSCHPTRSConfig;
ptrs.TimeDensity = 2;
ptrs.FrequencyDensity = 4;
ptrs.REOffset = '10';

Assign the PDSCH PT-RS configuration object to PTRS property of PDSCH configuration object.

pdsch.PTRS = ptrs;

Generate PDSCH PT-RS symbols of data type single.

sym = nrPDSCHPTRS(carrier,pdsch,'OutputDataType','single')
sym = 78x1 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

Generate PDSCH PT-RS indices in subscript form and set the index orientation to bandwidth part.

ind = nrPDSCHPTRSIndices(carrier,pdsch,'IndexStyle','subscript','IndexOrientation','bwp')
ind = 78x3 uint32 matrix

    19     1     1
    67     1     1
   115     1     1
   163     1     1
   211     1     1
   259     1     1
   307     1     1
   355     1     1
   403     1     1
   451     1     1

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.

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

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 the RE indexing form and base, respectively, of the output.

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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PT-RS resource element indices, returned as one of these values.

  • Column vector — The function returns this type of value when 'IndexStyle' is set to 'index'.

  • 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


[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™.

Version History

Introduced in R2020a

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