PDSCH configuration has three sections, PDSCH, PDSCH DM-RS, and PDSCH PT-RS.

PDSCH

The following configuration parameters specific to the PDSCH portion of the Downlink Signal.

Symbol Allocation: Specifies the symbol indices which are allocated to PDSCH in the resource map. The format is defined in the Range Format Specifiers section. Valid values for first and last symbol are 0 to 13, while the last symbol must be greater than or equal to the first symbol. The default is 0:13.

Slot Allocation: Specifies the indices of the allocated slots. The format is defined in the Range Format Specifiers section.

Valid values are between 0 and (Max. Slots in Frame - 1). The maximum number of slots in the current frame is displayed in the Max. Slots in Frame field. It depends on the selected Subcarrier Spacing.

RB Allocation: Specifies the range of the allocated Resource Blocks for PDSCH. The format is defined in the Range Format Specifiers section.

For more information about RB Allocation, refer to the following figure with configuration - Allocated slots 2:11, RB Allocation 1:13.

Channel Coding: Specifies whether channel coding is enabled. If enabled, modulation type is calculated from MCS Table and MCS Index parameters, otherwise the user specified value is honoured.

MCS Table: Specifies the modulation and coding scheme table to be used for channel coding.

MCS Table Value 3GPP 38.214 Reference
256QAM Table 5.1.3.1-2: MCS index table 2 for PDSCH
64QAM Table 5.1.3.1-1: MCS index table 1 for PDSCH
64QAM LowSE Table 5.1.3.1-3: MCS index table 3 for PDSCH
1024QAM Table 5.1.3.1-4: MCS index table 4 for PDSCH

LBRM Enabled: Specifies whether limited buffer rate matching is enabled.

Modulation Type/Modulation Type CW0: Specifies the modulation type. When channel coding is enabled, this parameter indicates the modulation type that is used based on the values of MCS Table and MCS Index.

MCS Index/MCS Index CW0: Specifies the MCS index from the selected table.

Redundancy Version/Redundancy Version CW0: Specifies the redundancy version to use for channel coding. Valid values are from 0 to 3.

The following parameters are available when the number of antennas is greater than 4.

Modulation Type CW1: Specifies the modulation type for code word 1. When channel coding is enabled, this indicates the modulation type that is being used based on the values of MCS Table and MCS Index.

MCS Index CW1: Specifies the MCS index from the selected table for code word 1.

Redundancy Version CW1: Specifies the redundancy version to use for channel coding for code word 1. Valid values are from 0 to 3.

Data Scrambling ID Mode: If you set this parameter to User Defined, the scrambling sequence generator will be initialized with the value specified in the Data Scrambling Id parameter.

If you set this parameter to Cell ID, the scrambling sequence generator will be initialized with the value specified in the Cell ID parameter in the Carrier Definition section.

Data Scrambling Id: Initializes the scrambling sequence generator. Valid values are 0 to 1023. This value is used only if you set the Data Scrambling ID Mode to User Defined.

PDSCH Power: Specifies the factor by which the PDSCH REs are scaled. This value is expressed in dB.

Max. Slots in Frame: Specifies the maximum number of slots available for a PDSCH configuration in the current bandwidth part configuration.

PDSCH DMRS

The following configuration parameters specific to the DMRS portion of the Downlink Signal.

DMRS Power Mode: Specifies whether the configured DMRS Power is honored or calculated from CDM Groups for reference signal generation.

DMRS Power: This parameter is used to set the DMRS power in dB relative to the PDSCH data power. The recommended DMRS Power depends on the chosen Number of DM-RS CDM Groups without data:

Number of CDM Groups DMRS Config Type 1 DMRS Config Type 2
1 0 dB 0 dB
2 3 dB 3 dB
3 - 4.77 dB

DMRS Config Type: Determines the way the DMRS is mapped to physical resources. Either Type 1 or Type 2 can be selected.

DMRS Duration: Specifies the DMRS symbol length. Valid values are Single Symbol and Double Symbol.

DMRS Type A Position: Configures the position of the first DMRS symbol if Type A DMRS mapping is selected. Valid values are 2 and 3. This value is ignored in case of Type B DMRS mapping.

DMRS Additional Positions: Specifies the positions of additional DMRS symbols. Valid values are 0, 1, 2, and 3. If 0 is selected, no additional DMRS symbols are added.

PDSCH Mapping Type: Allows you to choose between Type A and Type B mapping.

  • For Type A, the position of the first DMRS symbol can be set via the DMRS Type A Position field.
  • For Type B, the position of the first DMRS symbol is the lowest symbol index specified in the Active Symbol Map.

Number of CDM Groups: Specifies the number of DM-RS CDM groups without data parameter. Valid values are 1,2,3 – depending on the number of transmit antenna ports and DMRS Config Type.

DMRS Antenna Ports: Specifies the antenna ports used for DMRS transmission. The antenna ports are given as a comma separated list. The number of specified DMRS antenna is equal to the Number of Layers.

DMRS Release Version: Specifies the 3GPP release version for generating the DMRS sequence. Allows you to choose between 3GPP Release 15 and 3GPP Release 16.

  • For 3GPP Release 16, the DMRS sequence is generated as per section 7.4.1.1.1 of 3GPP TS 38.211 g00 specification.
  • For 3GPP Release 15, the DMRS sequence is generated as per section 7.4.1.1.1 of 3GPP TS 38.211 f80 specification.

DMRS Scrambling ID Mode: If you set this parameter to User Defined, the DMRS scrambling sequence generator will be initialized with the value specified in the DMRS Scrambling ID field.

If you set this parameter to Cell ID, the DMRS scrambling sequence generator will be initialized with the value specified in the Cell ID field in the Carrier Definition section.

DMRS Scrambling Id: Initializes the DMRS scrambling sequence generator. Valid values range from 0 to 65535. This value is only used if the DMRS Scrambling ID Mode is set to User Defined.

nSCID: The DMRS scrambling sequence generator will be initialized with a value that is calculated from the DMRS Scrambling ID and the nSCID. Valid values are 0 and 1. This value is only used if the DMRS Scrambling ID Mode is set to User Defined.

PDSCH PT-RS

The following configuration parameters specific to the phase tracking reference signal.

PTRS Enabled: Specifies whether to enable adding a PTRS to the waveform.

PTRS Power Mode: Specifies whether the PTRS power is set according to the 3GPP standard or as per user configuration. The default value is Standard.

Standard
User Defined
Sets the PDSCH PTRS power scaling, βPT-RS, according to the Table 4.1-2 of 3GPP TS 38.214 specification. The epre-Ratio is configured using PTRS EPRE Ratio parameter.
Sets the PUSCH PTRS power scaling, βPT-RS, to the value specified in the PTRS Power parameter.

PTRS EPRE Ratio: Specifies the epre-ratio configuration defined in the Table 4.1-2 of 3GPP TS 38.214 specification. This parameter selects the power scaling of the PTRS REs relative to PDSCH data REs. Allowed values are 0 (results in scaling depending on number of Layers) and 1 (no scaling).

PTRS Power: Specifies the power of the PTRS.

PTRS RE Offset: Specifies the resource element offset. This parameter along with the PTRS Frequency Density is used to calculate the subcarrier indices to which the PTRS shall be mapped. Valid values are 0, 1, 2, and 3.

PTRS Frequency Density: This parameter along with the PTRS RE Offset is used to calculate the subcarrier indices to which the PTRS shall be mapped. This parameter is used for CP-OFDM. This parameter is not used if transform precoding is enabled. Valid values are 2 and 4.

PTRS Time Density: This parameter is used to calculate the set of time indices defined relative to the start of the PDSCH allocation. Valid values are 1, 2, 4.

PTRS Antenna Port: Specifies the antenna ports used for PTRS transmission. The antenna port should be a subset of the DMRS antenna ports.