nrPDSCHDMRSConfig
Description
The nrPDSCHDMRSConfig
object sets demodulation reference signal
(DM-RS) configuration parameters for a physical downlink shared channel (PDSCH), as defined in
TS 38.211 Section 7.4.1.1 [1]. Use this object when setting
the DMRS
property of the nrPDSCHConfig
or nrWavegenPDSCHConfig
objects.
The object defines the properties of PDSCH DM-RS symbols and indices generation and the resource elements pattern not used for data in DM-RS symbol locations. The read-only properties of this object provide the DM-RS subcarrier locations within a resource block (RB), code division multiplexing (CDM) groups, and time and frequency weights for DM-RS symbols. By default, the object specifies a single symbol DM-RS at symbol index 2 (0-based) with configuration type 1 and antenna port 0.
Creation
Description
creates a DM-RS
configuration object for a PDSCH with default properties.dmrs
= nrPDSCHDMRSConfig
specifies properties using one or more name-value pair arguments. Enclose each property in
quotes. For example, dmrs
= nrPDSCHDMRSConfig(Name,Value
)'DMRSConfigurationType',1,'DMRSLength',2
specifies
a double-symbol DM-RS with configuration type 1. Unspecified properties take their default
values.
Properties
DMRSConfigurationType
— DM-RS configuration type
1
(default) | 2
DM-RS configuration type, specified as 1
or 2
.
This property is the higher-layer parameter dmrs-Type.
Data Types: double
DMRSReferencePoint
— Reference point for DM-RS sequence to subcarrier resource mapping
CRB0
(default) | PRB0
Reference point for the DM-RS sequence to subcarrier resource mapping, specified as one of these options.
PRB0
— When the reference point is subcarrier 0 of the physical resource block 0 (PRB 0) of the bandwidth part (BWP). Use this option when PDSCH is signalled by control resource set 0 (CORESET 0). For this case, the BWP parameters must align with CORESET 0.CRB0
— When the reference point is subcarrier 0 of the common resource block 0 (CRB 0)
Data Types: char
| string
DMRSTypeAPosition
— Position of first DM-RS OFDM symbol for mapping type A
2
(default) | 3
Position of the first DM-RS OFDM symbol for mapping type A, specified as
2
or 3
. This property is the higher-layer
parameter dmrs-TypeA-Position.
This property only applies when the MappingType
property of the
nrPDSCHConfig
or nrWavegenPDSCHConfig
object is set to 'A'
.
Data Types: double
DMRSAdditionalPosition
— Maximum number of DM-RS additional positions
0
(default) | 1
| 2
| 3
Maximum number of DM-RS additional positions, specified as 0
,
1
, 2
, or 3
. This property is
the higher-layer parameter dmrs-AdditionalPosition.
Data Types: double
DMRSLength
— Number of consecutive front-loaded DM-RS OFDM symbols
1
(default) | 2
Number of consecutive front-loaded DM-RS OFDM symbols, specified as
1
(single-symbol DM-RS) or 2
(double-symbol
DM-RS).
Data Types: double
CustomSymbolSet
— DM-RS OFDM symbol locations
[]
(default) | integer from 0 to 13 | vector of nonnegative integers
DM-RS OFDM symbol locations that are 0-based, specified as one of these options.
Integer from 0 to 13 — For one DM-RS symbol
Vector of nonnegative integers from 0 to 13 — For multiple DM-RS symbols
Each input symbol location is assumed to be a single-symbol DM-RS within the physical shared channel symbol allocation.
The default value, []
, corresponds to the DM-RS symbol locations,
as defined in TS 38.211 Table 7.4.1.1.2-3 or 7.4.1.1.2-4. Setting this property
overrides the corresponding DM-RS symbol locations in these standard lookup
tables.
Data Types: double
DMRSPortSet
— DM-RS antenna port indices
[]
(default) | vector of nonnegative integers
DM-RS antenna port indices, specified as a vector of nonnegative integers from 0 to 23. The valid range of antenna port indices depends on the DM-RS configuration type, DM-RS symbol duration, and whether enhanced DM-RS multiplexing is enabled, as described in this table.
DMRSEnhancedR18
Value | DMRSLength Value | Valid Range of Antenna Port Indices | |
---|---|---|---|
DMRSConfigurationType=1 | DMRSConfigurationType=2 | ||
0 for basic multiplexing | 1 for single symbol | [0, 3] | [0, 5] |
2 for double symbol | [0, 7] | [0, 11] | |
1 for enhanced multiplexing | 1 for single symbol | [0, 3] and [8, 11] | [0, 5] and [12, 17] |
2 for double symbol | [0, 15] | [0, 23] |
This table corresponds to the PDSCH DM-RS antenna port values, as defined in TS 38.211 Table 7.4.1.1.2-5. The value range from 0 to 23 in this table corresponds to the range from 1000 to 1023, respectively, in Table 7.4.1.1.2-5.
The default value, []
, implies that the object automatically
selects the first N valid port indices, where N is
the number of layers that is specified by the NumLayers
property of
the nrPDSCHConfig
or nrWavegenPDSCHConfig
objects. For example, if NumLayers=6
and the valid port indices are
in the range [0, 3] and [8, 11], then the object selects the 0, 1, 2, 3, 8, 9 port
indices.
Data Types: double
NIDNSCID
— DM-RS scrambling identities
[]
(default) | 1-by-2 integer vector | scalar integer
DM-RS scrambling identities (NID0 and NID1), specified as one of these options.
1-by-2 integer vector of values from 0 to 65,535 — The vector elements define NID0 and NID1.
Scalar integer from 0 to 65,535 — This option specifies equal values for both NID0 and NID1.
[]
— Use this option to set the DM-RS scrambling identity to the physical layer cell identity, specified by theNCellID
property of the carrier configuration.
Data Types: double
NSCID
— DM-RS scrambling initialization
0
(default) | 1
DM-RS scrambling initialization, specified as 0
or
1
.
Data Types: double
NumCDMGroupsWithoutData
— Number of DM-RS CDM groups without data
2
(default) | 1
| 3
Number of DM-RS CDM groups without data, specified as 1
,
2
, or 3
.
Each value indicates a different set of CDM group numbers, according to TS 38.214 Section 5.1.6.2.
1
— CDM group number 02
— CDM group numbers 0 and 13
— CDM group numbers 0, 1, and 2
Data Types: double
DMRSDownlinkR16
— Low PAPR DM-RS sequence
0
(default) | 1
Low peak-to-average-power ratio (PAPR) DM-RS sequence, specified as one of these logical values.
0
(false
) — Disable the use of low PAPR DM-RS.1
(true
) — Enable the use of low PAPR DM-RS. The DM-RS sequence generation depends on the DM-RS antenna port indices (DMRSPortSet
) as well as the scrambling initialization (NSCID
).
Data Types: double
CDMGroups
— CDM group numbers corresponding to each DM-RS port
0
(default) | integer from 0 to 2 | row vector of integers
This property is read-only.
CDM group numbers corresponding to each DM-RS port, specified as one of these options.
Integer from 0 to 2 — When
DMRSPortSet
property is a scalar, specifying single DM-RS antenna port.Row vector of integers from 0 to 2 — When
DMRSPortSet
property is a vector, specifying multiple DM-RS antenna ports. Each element corresponds to a CDM group number for that port.
Value of this property depends on the DMRSConfigurationType
property according to TS 38.211 Table 7.4.1.1.2-1 or 7.4.1.1.2-2 [1].
Data Types: double
DeltaShifts
— Delta shifts corresponding to each CDM group
0
(default) | integer from the set {0, 1, 2, 4} | row vector of integers
This property is read-only.
Delta shifts corresponding to each CDM group, specified as one of these options.
Integer from the set {0, 1, 2, 4} — When
DMRSPortSet
property is a scalar, specifying single DM-RS antenna port.Row vector of integers from the set {0, 1, 2, 4} — When
DMRSPortSet
property is a vector, specifying multiple DM-RS antenna ports. Each element corresponds to the delta shift to be applied for that port.
Value of this property depends on the DMRSConfigurationType
according to TS 38.211 Table 7.4.1.1.2-1 or 7.4.1.1.2-2 [1].
Data Types: double
FrequencyWeights
— Frequency weights
[1; 1]
(default) | column vector of integers | matrix of integers
This property is read-only.
Frequency weights for the DM-RS symbols, specified as one of these options.
Column vector of integers — When
DMRSPortSet
property is a scalar, specifying single DM-RS antenna port.Matrix of integers — When
DMRSPortSet
property is a vector, specifying multiple DM-RS antenna ports. Each column corresponds to the weights for that port.
Value of this property depends on the DMRSConfigurationType
according to TS 38.211 Table 7.4.1.1.2-1 or 7.4.1.1.2-2 [1].
Data Types: double
TimeWeights
— Time weights
[1; 1]
(default) | column vector of integers | matrix of integers
This property is read-only.
Time weights for to the DM-RS symbols, specified as one of these options.
Column vector of integers — When
DMRSPortSet
property is a scalar, specifying single DM-RS antenna port.Matrix of integers — When
DMRSPortSet
property is a vector, specifying multiple DM-RS antenna ports. Each column corresponds to the weights for that port.
Value of this property depends on the DMRSConfigurationType
according to TS 38.211 Table 7.4.1.1.2-1 or 7.4.1.1.2-2 [1].
Data Types: double
DMRSSubcarrierLocations
— Subcarrier locations in RB for each port
[0; 2; 4; 6; 8; 10]
(default) | column vector of integers | matrix of integers
This property is read-only.
Subcarrier locations in an RB for each port, specified as one of these options.
Column vector of integers — When
DMRSPortSet
property is a scalar, specifying single DM-RS antenna port.Matrix of integers — When
DMRSPortSet
property is a vector, specifying multiple DM-RS antenna ports. Each column corresponds to the subcarrier locations for that port.
Data Types: double
CDMLengths
— CDM arrangement for reference signals
[1 1]
(default) | two-element row vector
This property is read-only.
CDM arrangement for reference signals, specified as the comma-separated pair
consisting of 'CDMLengths'
and a two-element row vector of
nonnegative integers [FD
TD]. Array elements FD and TD
specify the length of CDM despreading in the frequency domain (FD-CDM) and time domain
(TD-CDM), respectively. A value of 1
for an element specifies no
CDM.
Data Types: double
DMRSEnhancedR18
— Enhanced DM-RS multiplexing
0
(default) | 1
Since R2024a
Enhanced DM-RS multiplexing, specified as one of these logical values:
0
(false
) — Disable enhanced DM-RS multiplexing.1
(true
) — Enable enhanced DM-RS multiplexing to extend the set of DM-RS antenna ports for MU-MIMO use.
This property together with the DMRSLength
and DMRSConfigurationType
properties define the valid range of antenna port
indices, as described in this table.
DMRSEnhancedR18
Value | DMRSLength Value | Valid Range of Antenna Port Indices | |
---|---|---|---|
DMRSConfigurationType=1 | DMRSConfigurationType=2 | ||
0 for basic multiplexing | 1 for single symbol | [0, 3] | [0, 5] |
2 for double symbol | [0, 7] | [0, 11] | |
1 for enhanced multiplexing | 1 for single symbol | [0, 3] and [8, 11] | [0, 5] and [12, 17] |
2 for double symbol | [0, 15] | [0, 23] |
Data Types: double
Examples
Create PDSCH DM-RS Object
Create a physical downlink shared channel (PDSCH) demodulation reference signal (DM-RS) object.
Specify a single-symbol DMRS with configuration type as 2, number of DM-RS additional positions as 2, and antenna ports as 0, 1, and 3.
View the corresponding properties.
dmrs = nrPDSCHDMRSConfig; dmrs.DMRSConfigurationType = 2; dmrs.DMRSLength = 1; dmrs.DMRSAdditionalPosition = 2; dmrs.DMRSPortSet = [0 1 3]; dmrs
dmrs = nrPDSCHDMRSConfig with properties: DMRSConfigurationType: 2 DMRSReferencePoint: 'CRB0' DMRSTypeAPosition: 2 DMRSAdditionalPosition: 2 DMRSLength: 1 CustomSymbolSet: [] DMRSPortSet: [0 1 3] NIDNSCID: [] NSCID: 0 NumCDMGroupsWithoutData: 2 DMRSDownlinkR16: 0 DMRSEnhancedR18: 0 Read-only properties: CDMGroups: [0 0 1] DeltaShifts: [0 0 2] FrequencyWeights: [2x3 double] TimeWeights: [2x3 double] DMRSSubcarrierLocations: [4x3 double] CDMLengths: [2 1]
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');
References
[1] 3GPP TS 38.211. “NR; Physical channels and modulation.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network.
[2] 3GPP TS 38.214. “NR; Physical layer procedures for data.” 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 R2020aR2024a: Use enhanced DM-RS multiplexing for MU-MIMO
Use the DMRSEnhancedR18
object property to enable enhanced DM-RS multiplexing for
MU-MIMO transmissions.
R2024a: Value range of DMRSPortSet
property has changed
The value range of the DMRSPortSet
property has changed to match the PDSCH DM-RS antenna port values
from TS 38.211 Table 7.4.1.1.2-5. In previous releases, the valid antenna port numbers range
from 0 to 11 and the nominal value depends on the DM-RS configuration type and DM-RS symbol
duration. Starting in R2024a, the valid antenna port numbers range from 0 to 23 and the
nominal value also depends on whether enhanced DM-RS multiplexing is enabled.
The range from 0 to 23 in
the DMRSPortSet
property corresponds to the range from 1000 to 1023,
respectively, in Table 7.4.1.1.2-5.
R2022a: Release 16 updates for low PAPR sequences, DM-RS scrambling identities, and type B mapping
The
DMRSDownlinkR16
property enables low peak-to-average-power ratio (PAPR) physical downlink shared channel (PDSCH) DM-RS sequences, as defined in Release 16 of TS 38.211 Section 7.4.1.1.The
NIDNSCID
property supports dynamic ID selection.PDSCH DM-RS symbol generation now supports type B mapping DM-RS symbol positions, as defined in Release 16 of TS 38.211 Tables 7.4.1.1.2-3 and 7.4.1.1.2-4.
See Also
Functions
Objects
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