How can I embed a data matrix into DMRS in 5G-NR?

How can I embed a 40*8 char size data matrix into a DMRS signal using 5G-NR in the Matlab environment?

(While doing this, PDSCH can be used.)

[Garmit Pant]

Hello ÖMER FARUK ORUÇ

Can you please share the MATLAB code that you are using and also clarify what is the downstream task that you need to do with the DMRS signal?

Regards

Answer 1

[Garmit Pant]

Hello ÖMER FARUK ORUÇ

From what I gather, you are working with Demodulation Reference Signal (DMRS) in a 5G New Radio (NR) context. You want to embed your own data into the DMRS that is available in the form of 40x8 character array representing binary data.

DMRS is typically used for channel estimation. Embedding user data, replacing the standard DMRS symbols, is not compliant with 5G NR standards. You can still simulate the operation by modulating the binary data and mapping it onto a resource grid. The following code snippet shows you how to do so.

% Define the size of the data matrix and generate random data 
% Replace “dataMatrix” with your data 
numRows = 40; 
numCols = 8; 
dataMatrix = char(randi([0, 1], numRows, numCols) + '0'); % '0' and '1' characters 

% Convert the character matrix to a binary sequence 
binarySequence = (dataMatrix - '0').'; % Convert to binary and transpose to get a column vector 

% Modulate the binary sequence using BPSK (since the data is binary) 
modulatedData = nrSymbolModulate(binarySequence(:), 'BPSK'); 

% Create a carrier configuration object with default settings 
carrierConfig = nrCarrierConfig(); 

% Create a PDSCH configuration object with default settings 
pdschConfig = nrPDSCHConfig(); 

% Generate DMRS symbols and indices 
dmrsSymbols = nrPDSCHDMRS(carrierConfig, pdschConfig); 
dmrsIndices = nrPDSCHDMRSIndices(carrierConfig, pdschConfig); 

% Create the resource grid 
K = carrierConfig.NSizeGrid * 12; % Number of subcarriers 
L = 14; % Number of OFDM symbols in a slot 
resourceGrid = zeros(K, L); 

% Map the modulated data to the DMRS indices 
% This is not standard-compliant and for simulation purposes only 
resourceGrid(dmrsIndices) = modulatedData(1:length(dmrsIndices)); 

% Perform the OFDM modulation to generate the time-domain waveform 
ofdmWaveform = nrOFDMModulate(carrierConfig, resourceGrid); 

% The waveform 'ofdmWaveform' now contains the non-standard DMRS-like data and can be 
% further processed for transmission in a simulation environment. 
% Visualise the waveform 
figure; 
plot(real(ofdmWaveform)); 
title('OFDM Waveform Time-Domain Representation'); 
xlabel('Sample Index'); 
ylabel('Amplitude'); 
grid on; 

Please note that this is a link level simulation and this operation is not possible for a system level simulation.

For further understanding, refer to the following MATLAB Documentation:

1. “nrSymbolModulate” function: https://www.mathworks.com/help/5g/ref/nrsymbolmodulate.html
2. “nrOFDMModulate” function: https://www.mathworks.com/help/5g/ref/nrofdmmodulate.html

I hope you find the above explanation and suggestions useful!