Documentation

lteLayerDemap

Layer demapping onto scrambled and modulated codewords

Syntax

  • out = lteLayerDemap(in,ncw)
  • out = lteLayerDemap(in,ncw,txscheme)
    example
  • out = lteLayerDemap(chs,in)

Description

out = lteLayerDemap(in,ncw) performs the layer demapping required to undo the processing described in TS 36.211, Sections 5.3.2A and 6.3.3 [1]. The function returns out, a cell array containing one, or two vectors of modulation symbols, one for each codeword. The function demaps the NU layers specified in the M-by-NU matrix in into ncw codewords using 'Port0' transmission scheme if NU = 1 and 'SpatialMux' transmission scheme otherwise.

example

out = lteLayerDemap(in,ncw,txscheme) performs the layer demapping using the transmission scheme, txscheme.

out = lteLayerDemap(chs,in) demaps the NU layers specified in the M-by-NU matrix in into codeword vectors out, according to the parameters specified in the channel transmission configuration structure, chs.

The number of codewords is established from the number of modulation formats in the Modulation field. This value enables you to return the correct number of codewords when using chs specified in ltePDSCH or ltePUSCH on the transmit side. Alternatively, you can specify the number of codewords directly in the NCodewords field. The NCodewords field takes precedence if present.

Examples

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Demap Codeword for Transmit Diversity

Map a codeword onto four symbols for 'TxDiversity' transmission scheme. Recover the codeword by demapping the four layers onto one codeword.

nCodewords = 1;
codeword = ones(16,1);
nLayers = 4;
txScheme = 'TxDiversity';

layerMap = lteLayerMap(codeword,nLayers,txScheme);

out = lteLayerDemap(layerMap,nCodewords,txScheme);

Input Arguments

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in — Modulation symbolsnumeric matrix

Modulation symbols, specified as an M-by-NU numeric matrix consisting of M modulation symbols for NU transmission layers. You can generate this matrix by lteDLDeprecode or ltePUSCHDeprecode.

Data Types: double
Complex Number Support: Yes

ncw — Number of codewords1 | 2

Number of codewords, specified as 1 or 2.

Data Types: double

txscheme — Transmission scheme'Port0' (default) | 'TxDiversity' | 'CDD' | 'SpatialMux' | 'MultiUser' | 'Port5' | 'Port7-8' | 'Port8' | 'Port7-14'

Transmission scheme, specified as one of the following options.

  • 'SpatialMux' — Closed-loop spatial multiplexing.

  • 'Port0' — Single-antenna port, port 0.

  • 'TxDiversity' — Transmit diversity scheme.

  • 'CDD' — Large delay cyclic delay diversity scheme.

  • 'MultiUser' — Multiuser MIMO scheme.

  • 'Port5' — Single-antenna port, port 5.

  • 'Port7-8' — Single-antenna port, port 7 (NLayers = 1). Dual layer transmission, ports 7 and 8 (NLayers = 2).

  • 'Port8' — Single-antenna port, port 8.

  • 'Port7-14' — Up to eight-layer transmission, ports 7–14.

Data Types: char

chs — Channel-specific transmission configurationstructure

Channel-specific transmission configuration, specified as a structure that can contain the following parameter fields.

Parameter FieldRequired or OptionalValuesDescription
TxSchemeOptional

'Port0' (default), 'TxDiversity', 'CDD', 'SpatialMux' (default), 'MultiUser', 'Port5', 'Port7-8', 'Port8', 'Port7-14'

Transmission scheme, specified as one of the following options.

  • 'SpatialMux' — Closed-loop spatial multiplexing.

  • 'Port0' — Single-antenna port, port 0.

  • 'TxDiversity' — Transmit diversity scheme.

  • 'CDD' — Large delay cyclic delay diversity scheme.

  • 'MultiUser' — Multiuser MIMO scheme.

  • 'Port5' — Single-antenna port, port 5.

  • 'Port7-8' — Single-antenna port, port 7 (NLayers = 1). Dual layer transmission, ports 7 and 8 (NLayers = 2).

  • 'Port8' — Single-antenna port, port 8.

  • 'Port7-14' — Up to eight-layer transmission, ports 7–14.

Also specify one of these fields:
  ModulationRequired if NCodewords is not set

('QPSK', '16QAM', '64QAM', '256QAM') String or cell array of strings.

Modulation type, specified as a string or cell array of strings. If 2 blocks, each cell is associated with a transport block.

  NCodewordsRequired if Modulation is not set

1, 2

Number of codewords

Output Arguments

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out — Modulation symbolscell array of one or two vectors

Modulation symbols, specified as a cell array of one or two vectors. The cell array contains one or two vectors of symbols, one for each codeword.

Data Types: cell

References

[1] 3GPP TS 36.211. "Physical Channels and Modulation." 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA). URL: http://www.3gpp.org.

Introduced in R2014a

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