Modulation and Coding (PDSCH, 6GR)

The Modulation and Coding group of the PDSCH tab. All parameters are auto-coupled — see Auto and Manual Parameter Coupling.

Five of the settings in this group — MCS, Redundancy Version, Modulation, Coding Rate, and Transport Block Size — are laid out as a grid with a Codeword 1 and a Codeword 2 column. The second column is unavailable unless the channel carries two codewords; see Number of Codewords / Layers.

MCS modulation and coding scheme Table - Selects the modulation and coding scheme table. 3GPP scopes the MCS tables by clause rather than per channel, so a PDSCH Physical Downlink Shared Channel offers only the tables that are legal for the downlink.

Table 64QAM - The 64QAM MCS table, per 3GPP TS Technical Specification 38.214 Table 5.1.3.1-1 (CP 1) Contention period, or 2) Cyclic prefix-OFDM Orthogonal Frequency Division Multiplexing: OFDM employs multiple overlapping radio frequency carriers, each operating at a carefully chosen frequency that is Orthogonal to the others, to produce a transmission scheme that supports higher bit rates due to parallel channel operation. OFDM is an alternative tranmission scheme to DSSS and FHSS., 256QAM not configured).
Table 256QAM - The 256QAM MCS table, per Table 5.1.3.1-2.
Table 64QAM LowSE - The 64QAM low spectral efficiency MCS table, per Table 5.1.3.1-3.
Table 1024QAM - The 1024QAM MCS table, per Table 5.1.3.1-4. 1024QAM is defined for the downlink only, so this table appears on the PDSCH and nowhere else.

Default: Table 64QAM

Choices: Table 64QAM, Table 256QAM, Table 64QAM LowSE, Table 1024QAM

xOverhead / TB Scaling - One row holding two values used in the transport block size calculation. xOverhead sets the number of resource elements per resource block reserved for overhead — for example CSI channel state information-RS or a CORESET. TB Scaling Factor sets the factor the transport block size is scaled by.

Default: xOverhead 0; TB Scaling Factor 1

Choices: xOverhead 0, 6, 12, 18. TB Scaling Factor 1, 0.5, 0.25

MCS - Sets the modulation and coding scheme index within the selected table, per codeword. Both codewords are read through the same MCS Table, because 3GPP configures the MCS table per channel rather than per codeword.

Default: 0

Range: 0 to 31

Redundancy Version - Sets the redundancy version per codeword, which selects which part of the encoded transport block was transmitted (3GPP TS 38.212). Value 0 is an initial transmission. This affects the decoded bits rather than the constellation, so an incorrect value shows up as a failed CRC Cyclic Redundancy Check rather than as degraded EVM Error vector magnitude (EVM): A quality metric in digital communication systems. See the EVM metric in the Error Summary Table topic in each demodulator for more information on how EVM is calculated for that modulation format.. The two codewords are managed independently, so their values need not match.

Default: 0

Range: 0 to 3

Modulation / Coding Rate - (Read-only) Report the modulation format and coding rate implied by the MCS table and index, per codeword (QPSK Quadrature phase shift keying and 120/1024 at MCS 0).

Transport Block Size - (Read-only) Reports the transport block size, in bits, per codeword. Computed per 3GPP TS 38.214 §5.1.3.2 from the current MCS and resource allocation, the DMRS overhead, xOverhead, and TB Scaling Factor.