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Generate PDSCH PT-RS symbols



sym = nrPDSCHPTRS(carrier,pdsch) returns sym, which contains phase tracking reference signal (PT-RS) symbols of the physical downlink shared channel (PDSCH), as defined in TS 38.211 Section [1]. carrier specifies the carrier configuration parameters for a specific OFDM numerology and pdsch specifies the PDSCH configuration parameters.

sym = nrPDSCHPTRS(carrier,pdsch,'OutputDataType',datatype) specifies the data type of the output PT-RS symbols.


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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.

Property FieldValuesDescription

1 (default), integer from 0 to 1007

Physical layer cell identity


15 (default), 30, 60, 120, 240

Subcarrier spacing in kHz


'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.


52 (default), integer from 1 to 275

Number of resource blocks in the carrier resource grid


0 (default), integer from 0 to 2199

Start of carrier resource grid relative to common resource block 0 (CRB 0)


0 (default), nonnegative integer scalar

Slot number. You can set NSlot to a value larger than the number of slots per frame.

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

Property FieldValuesDescription

[] (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.


[] (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.


nrPDSCHReservedConfig (default), cell array of nrPDSCHReservedConfig objects

Reserved PRBs and OFDM symbols pattern in BWP, specified as a cell array of objects, of class nrPDSCHReservedConfig.


[] (default), nonnegative integer vector

Reserved resource elements (RE) indices within the BWP


1 (default), integer from 1 to 8

Number of transmission layers. For one codeword, use an integer between 1 to 4. For two codewords, use an integer between 5 to 8.


'A' (default), 'B'

Mapping type of PDSCH


[0 14] (default), two-element vector of nonnegative integers

OFDM symbols allocated for PDSCH


[0:51] (default), vector of nonnegative integer from 0 to 274

PRBs allocated for PDSCH within the BWP


1 (default), integer from 0 to 65,535

Radio network temporary identifier of the user equipment


nrPDSCHDMRSConfig configuration object

DMRS configuration object only uses these properties.

  • DMRSConfigurationType

  • DMRSReferencePoint

  • DMRSTypeAPosition

  • DMRSLength

  • DMRSAdditionalPosition

  • CustomSymbolSet

  • DMRSPortSet



For more information, see nrPDSCHDMRSConfig.


0 (default), 1

PT-RS configuration, specified as one of these values.

  • 0 — Disable PT-RS configuration.

  • 1 — Enable PT-RS configuration.


nrPDSCHPTRSConfig configuration object

PDSCH PT-RS configuration, specified as a nrPDSCHPTRSConfig configuration object.

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

Data Types: char | string

Output Arguments

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PT-RS symbols, returned as a complex column vector.

Data Types: double | single
Complex Number Support: Yes


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

Extended Capabilities

Introduced in R2020a