comnum.NrPdsch#

class comnum.NrPdsch(n_rb_grid, prb_start, n_prb, qm, *, first_symbol=2, n_symbols=12, dmrs_type_a_position=2, dmrs_additional_position=0, n_ports=1, prg_size=2, rnti=1, n_id=0, dmrs_n_id=0, slot=0, subcarrier_spacing_hz=15000.0)#

One slot of a single-layer PDSCH (TS 38.211 Sec. 7.3.1): scrambling, modulation, resource mapping around the DM-RS of port 1000 (configuration type 1, one CDM group without data), a precoder per PRG, and a receiver that estimates the precoded channel on the DM-RS by robust 2-D Wiener filtering.

Parameters:

  • n_rb_grid (int) – the resource blocks of the carrier.

  • prb_start (int) – the first PRB of the allocation.

  • n_prb (int) – the PRBs of the allocation.

  • qm (int) – the bits per symbol.

  • first_symbol (int) – the first PDSCH symbol.

  • n_symbols (int) – the PDSCH symbols.

  • dmrs_type_a_position (int) – 2 or 3.

  • dmrs_additional_position (int) – 0 to 3.

  • n_ports (int) – the transmit ports, 1 or 2.

  • prg_size (int) – the PRBs per precoding group.

  • rnti (int) – the RNTI of the scrambling.

  • n_id (int) – the scrambling identity.

  • dmrs_n_id (int) – the DM-RS scrambling identity.

  • slot (int) – the slot in the frame (the DM-RS sequence).

  • subcarrier_spacing_hz (float) – the subcarrier spacing.

Raises:

ValueError – for an invalid configuration (when used).

Examples

>>> import comnum
>>> p = comnum.NrPdsch(52, 23, 6, 2, dmrs_additional_position=1)
>>> p.g(), p.n_prgs
(1584, 4)
data_res(reserved=None)#

The data REs of the slot in their mapping order (frequency first).

Parameters:

reserved (array_like | None) – REs (symbol, subcarrier) not used for data.

Returns:

(n, 2) pairs (symbol, subcarrier).

Return type:

numpy.ndarray

Raises:

ValueError – for an invalid configuration.

g(reserved=None)#

The channel bits G of the slot.

Parameters:

reserved (array_like | None) – REs (symbol, subcarrier) not used for data.

Returns:

G.

Return type:

int

Raises:

ValueError – for an invalid configuration.

receive(rx, noise_var, *, max_delay_s=4.69e-06, max_doppler_hz=100.0, reserved=None)#

The descrambled LLRs of a received slot.

Parameters:

  • rx (array_like) – (n_rx, 14, 12 n_rb_grid) received resource elements.

  • noise_var (float) – the noise variance per RE and antenna.

  • max_delay_s (float) – the largest delay the estimator expects.

  • max_doppler_hz (float) – the largest Doppler shift it expects.

  • reserved (array_like | None) – REs (symbol, subcarrier) without data.

Returns:

the g LLRs (positive for a 0).

Return type:

numpy.ndarray

Raises:

ValueError – for grids of another size or a non-positive noise variance.

transmit(bits, precoders=None, reserved=None)#

The grids of the slot carrying the g channel bits.

Parameters:

  • bits (array_like) – the channel bits (NrTransportBlock.encode).

  • precoders (array_like | None) – the precoder index of every PRG (0 to 3), zeros by default.

  • reserved (array_like | None) – REs (symbol, subcarrier) left empty.

Returns:

(n_ports, 14, 12 n_rb_grid) resource elements.

Return type:

numpy.ndarray

Raises:

ValueError – for bits of another length or one precoder per PRG missing.

n_prgs#

The precoding resource block groups of the allocation.

Type:

int