lteLayerDemap

Layer demapping onto scrambled and modulated codewords

Syntax

out = lteLayerDemap(in,ncw)

out = lteLayerDemap(in,ncw,txscheme)

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 input matrix, in, into ncw codewords using 'Port0' transmission scheme if NU = 1 and 'SpatialMux' transmission scheme otherwise.

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

out = lteLayerDemap(chs,in) performs layer demapping according to the parameters specified in the channel transmission configuration structure, chs.

Examples

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

in — Modulation symbols

numeric 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 using lteDLDeprecode or ltePUSCHDeprecode.

Data Types: double
Complex Number Support: Yes

ncw — Number of codewords

1 | 2

Number of codewords, specified as 1 or 2.

Data Types: double

txscheme — Transmission scheme

'Port0' | 'TxDiversity' | 'CDD' | 'SpatialMux' | 'MultiUser' | 'Port5' | 'Port7-8' | 'Port8' | 'Port7-14'

PDSCH transmission scheme, specified as one of the following options.

Transmission scheme	Description
'Port0'	Single antenna port, port 0
'TxDiversity'	Transmit diversity
'CDD'	Large delay cyclic delay diversity scheme
'SpatialMux'	Closed loop spatial multiplexing
'MultiUser'	Multi-user MIMO
'Port5'	Single-antenna port, port 5
'Port7-8'	Single-antenna port, port 7, when NLayers = 1. Dual layer transmission, ports 7 and 8, when NLayers = 2.
'Port8'	Single-antenna port, port 8
'Port7-14'	Up to eight layer transmission, ports 7–14

When provided as an optional input this setting overrides any setting provided in chs.TxScheme.

Data Types: char | string

chs — Channel-specific transmission configuration

structure

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

Parameter Field	Required or Optional	Values	Description
TxScheme	Optional	'Port0', 'TxDiversity', 'CDD', 'SpatialMux', 'MultiUser', 'Port5', 'Port7-8', 'Port8', 'Port7-14'. The default TxScheme is 'Port0' for NLayers = 1, and 'SpatialMux' otherwise.	PDSCH transmission scheme, specified as one of the following options. Transmission scheme Description 'Port0' Single antenna port, port 0 'TxDiversity' Transmit diversity 'CDD' Large delay cyclic delay diversity scheme 'SpatialMux' Closed loop spatial multiplexing 'MultiUser' Multi-user MIMO 'Port5' Single-antenna port, port 5 'Port7-8' Single-antenna port, port 7, when NLayers = 1. Dual layer transmission, ports 7 and 8, when NLayers = 2. 'Port8' Single-antenna port, port 8 'Port7-14' Up to eight layer transmission, ports 7–14
Also specify one of these fields:
Modulation	Required, if NCodewords is not set	'QPSK', '16QAM', '64QAM', '256QAM', '1024QAM'	Modulation type, specified as a character vector, cell array of character vectors, or string array. If blocks, each cell is associated with a transport block.
NCodewords	Required, if Modulation is not set	1, 2	Number of codewords
The number of codewords is established from the number of modulation formats in the Modulation field. This allows the correct number of codewords to be returned by using the channel transmission configuration structure chs as provided to the ltePDSCH or ltePUSCH function on the transmit side. Alternatively the number of codewords can be directly specified in the NCodewords field. The NCodewords field takes precedence if present.

Output Arguments

out — Modulation symbols

cell 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. “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation.” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network. URL: https://www.3gpp.org.

Version History

Introduced in R2014a